Wheel Running Research Articles

Alterations in sphingolipid synthesis during training, detraining, and retraining may alter myogenesis in skeletal muscle

The benefits of exercise on metabolic health and its effectiveness at reducing morbidity risk are well established. Exercise training enhances skeletal muscle metabolism and function, but whether such adaptations persist through detraining and how they are potentiated with retraining are not well understood. Recent evidence has highlighted the role sphingolipids play on skeletal muscle size and function, but how exercise affects sphingolipid metabolism is not yet known. We hypothesize that alterations in skeletal muscle sphingolipid metabolism with exercise training are necessary to enhance muscle mass with further exercise retraining. Here, mice were SEDentary (SED; static cages) or exercise-TRAINed (TRAIN; voluntary wheel running) and chow-fed. We performed body composition analysis (using EchoMRI) and skeletal muscle collection [tibialis anterior ( TA), extensor digitorum longus ( EDL), gastrocnemius ( Gas), Soleus ( Sol), plantaris ( Plant), and levator ani ( LA)] following training (4wks), detraining (8wk), and retraining (12wk) in three independent cohorts. Sphingolipid and myogenic gene expression was measured in TA muscle by qPCR. Exercise training concomitantly increased lean and decreased fat percentage ( p<0.05), while increasing Sol muscle mass in TRAIN mice ( p<0.05), compared to SED. This was accompanied by higher sphingolipid metabolism ( Acer1, p<0.05; and Cers1, p=0.058) and myogenic gene expression ( MyoD, Myf5; p<0.05). Following detraining, TRAIN mice had an overall increase in lean-to-fat mass ( p<0.05) while maintaining all individual muscle masses ( p<0.05), compared to SED. This was accompanied by a reduction in gene expression of the sphingolipid receptor S1pr1 and myogenic factor Myf5 ( p<0.05), but no differences in sphingolipid metabolism ( Acer1, Cers1). Lastly, retraining increased lean and decreased fat percentage ( p<0.05) and enhanced the masses of TA, Gas, Sol, and Plant muscles in TRAIN mice ( p<0.05), compared to SED. This was accompanied by a reduced expression of rate limiting sphingolipid synthesis genes Sptlc1 and Sptlc2 and the kinase Sphk1 ( p<0.05), but no differences in Cers1 or myogenic gene expression in TRAIN mice, compared to SED. Overall, our data shows that exercise training and retraining potentiate muscle mass accretion and dynamically regulates sphingolipid metabolism adaptations. These data suggest a potential role for sphingolipids to modulate long-lasting improvements to skeletal muscle. Funding was provided by the University of Illinois Urbana-Champaign. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Metabolic dysfunction in the myocardium three months after exertional heat stroke in mice

In humans, exposure to heat stroke has proven to be a risk factor for development of cardiovascular disease later in life. We hypothesized that exposure to exertional heat stroke (EHS) would result in the development of similar long-term cardiac disease in mice. In this study we followed mice for three months after EHS, using ultrasound imaging of the heart, metabolomics and histological analysis of ventricular tissue and biomarker analysis after 4 weeks of recovery. Methods: Mice were instrumented with temperature telemetry devices and were trained to run on forced running wheels using an incremental exercise protocol. EHS mice ran in an temperature elevated environmental chamber; females 37.5°C; males 34°C; whereas, matched exercise control mice (EXC) ran in 22-23°C. Running stopped when EHS mice reached symptom limitation (unconsciousness). The mice were followed for 12 wks post EHS, with two ultrasound measures at 2 and 10 wks of recovery. At the end of the study, mice were anesthetized, a blood sample drawn, and ventricular tissue collected for metabolomics. RESULTS: Male but not female EHS mice gained ~10% greater body mass compared to EXC over the course of recovery ( P<0.01). Hearts from male but not female EHS mice exhibited elevations in heart mass per tibia length ( P<0.01). At three months, metabolomics in male EHS hearts revealed significant elevations in glucose and glucose metabolites and significant decreases in acylcarnitines consistent with a metabolic shift toward glucose and away from lipid metabolism. In contrast, female hearts exhibited fewer abnormalities but with significant elevations in lipid and arachidonate metabolites. At two weeks post, there were no differences in male ultrasound measures between EHS and EXC mice but in females there was a reduced posterior wall velocity ( P=0.012) and a trend towards narrower posterior wall thickness ( P= 0.06) . Between 2 and 12 wks post EHS, there were significant elevations in fractional shortening in males ( P<0.05) and elevations in posterior wall velocity ( P<0.01). In contrast, females exhibited significant reductions posterior wall velocity. From blood samples, male EHS mice had increased HDL and females exhibited decreased HDL (p<0.01 in both). LDL increased only in males P<0.05. Vascular adhesion molecules sICAM ( P<0.01) and Pecam1 ( P<0.01) were significantly decreased in EHS males and females and e-Selectin was decreased in EHS males only ( P<0.001). Total serum protein was significantly reduced in both male and females ( P<0.01). Male EHS mice also exhibited significant elevations in white blood cell count and total lymphocytes ( P=0.01) suggesting ongoing activation of the immune system . CONCLUSIONS: In this controlled preclinical model of EHS, both male and female mice exhibited long-lasting cardiovascular and systemic disorders that could account for the lingering incidence of cardiovascular disease and poor overall health in heat stroke victims. Supported by US Army Med. Research and Devel. Command BA180078 and the BK and Betty Stevens Endowment. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Abstract 2037: Investigating Changes In Satellite Cell Proliferation And Angiogenic Potential In Response To Exercise

Background: Peripheral Artery Disease (PAD) is an atherosclerotic process leading to vessel obstruction. Supervised walking exercise is a first-line treatment to improve walking ability and quality of life scores of patients. Despite its known benefits, the underlying mechanism is not fully understood. Thus, this study focuses on satellite cells (SCs), known for their role in muscular regeneration but also found to have an under investigated role as mediators of vascular growth through the secretion of cytokines and growth factors. Previous in vivo models have demonstrated increased migration of endothelial cells and smooth muscle cells, as well as blood vessel growth in response to SC activity. Aims: The project aims to enhance the efficacy of exercise therapy through a better understanding satellite cell biology and their pro-vasculogenic ability. Hypothesis: Exercise therapy will enhance SCs proliferation and secretion of paracrine growth factors inducing increased cell migration and vascular growth. Methods: Aortic Ring Assay: Murine thoracic aortic sections were embedded in a Type I collagen matrix in 96-wells. The wells were seeded with Opti-MEM (control), Opti-MEM+0.3% Vascular Endothelial Growth Factors (VEGF)(+ control), SC Conditioned Media (CM) (24hr incubation, 2M cells/plate), or denatured CM (56°C, 1 hr). The total length and number of branches were measured via ImageJ. Flow Cytometry: 18+ months old C57BL/6 were housed with voluntary running wheels with activity counter until day 28. Satellite cells were mechanically and chemically digested and were labeled as: CD11b-, CD45-, CD31-, Sca1-, and α7-integrin+ at 7-day intervals. Results: Aortic Ring Assay: SC CM showed significantly higher total branch length (13381.89±2470.44μm, n=6) (****p<0.0001) and numbers (19.24±3.87, n=6) (**p<0.01) compared to control (2158.18±382.31μm, n=9), (5.76±0.81, n=9). Flow Cytometry: SC proportion on day 21 (2.55±0.14,n=2) was significantly higher than control (1.54±0.298,n=8)(*p<0.05). Conclusion(s): These findings indicate that SC CM induces angiogenesis by secreting pro-angiogenic factors. The angiogenic activities could potentially be heightened through the proliferation of SCs under exercise therapy.

Previous exercise training history reduces drug addiction through brain orexinergic pathway in rodents: Conditioned Place Preference (CPP) model

Methamphetamine, commonly known as METH, is a potent and highly addict-forming stimulant substance that has a significant impact on the brain and poses a substantial health challenge in certain areas. Previous studies have pointed to the involvement of orexinergic pathway in reward-related behavior which is directly involved in acquisition phase of METH induced conditioned place preference (CPP). Besides, while numerous studies have explored the impact of exercise training on METH addiction, there is a limited body of research investigating as a form of preconditioning to prevent drug dependence. In this study, 48 male Wistar rats were assigned into six groups: Saline control, METH1 control, METH2 control, METH1 exercise, METH2 exercise. The exercise groups underwent eight weeks of forced running wheel training, five days a week, at 65% of their maximum running speed (Vmax). Following preconditioning with exercise training, METH groups received intraperitoneal (IP) methamphetamine injections at doses of 1 mg/kg (METH1 control, METH1 exercise) and 2 mg/kg (METH2 control, METH2 exercise) for five days to induce addiction (acquisition phase) according to the CPP model. Immediately following conditioning, hippocampus tissues were extracted to measure OX1R levels using western blotting. The results of the study indicated the conditioning of rats in both METH1 and METH2 control groups while preconditioning with exercise training prevent the addiction with low does of METH and only induced acquisition with double does in METH2 exercise group represented with reduced CPP scores in compare with METH2 control group (p<0.05). Molecular analysis revealed a significant increased in OX1R levels according to METH administration in hippocampus, although exercise training appeared to inhibit OX1R expression. Only conditioning with a high dose of METH was able to increase OX1R levels significantly. As these molecular results are in line with CPP scores it could further support the role of orexinergic pathway in addiction behavior in hippocampus. Furthermore, previous exercise training seems to affect this pathway and prevent conditioning with METH in an effective manner which suggests adaptation in the mesolimbic reward pathway protecting against methamphetamine addiction. Further investigation is warranted to find out the effectiveness of different training interventions in orexinergic pathway to inhibit dependance to METH. In this study, there was no external funding or financial support provided. This work was entirely self-funded by the authors. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Development of an Exercise-based EV Therapy to Improve Skeletal Muscle Recovery After Immobilization

Introduction: Immobilization is necessary for recovery from illness or bone fractures; however, prolonged immobilization can result in significant loss of muscle mass and function. It is critical to recover muscle mass quickly following immobilization as severe muscle atrophy is correlated with increased likelihood of metabolic disorders, disability, and mortality. Physical rehabilitation can improve outcomes but is not always feasible. The purpose is to determine the extent to which EVs circulating in blood after endurance exercise training (EnVs) act as a safe and effective therapy to recover skeletal muscle mass following disuse. Methods: Donor C57BL/6 mice (n = 8-10, 4-month-old) were provided access to horizontal running wheels in a locked (sedentary) or unlocked (exercise) condition. After 4 weeks of voluntary running, EVs (SedVs or EnVs) were isolated from plasma using size exclusion chromatography according to manufactures guidelines, and concentration confirmed via nanoparticle tracking analysis (NanoSight NS3000). Recipient C57BL6/J mice (n = 5-8, 4-month-old) were subjected to single limb immobilization for 14 days. Upon remobilization, mice received a single intramuscular injection of PBS, SedVs, EnVs, or endurance plasma proteins, and remobilized for 3 and 14 days. Muscle samples were collected after remobilization and assessed for muscle cross-sectional-area (CSA) and capillarization. Results: Upon 3-day remobilization, EnVs did not significantly recover global fiber CSA and fiber-type specific CSA (Type IIa, Type IIx or Type IIb) or capillarization. Upon 14-day remobilization, EnVs did not significantly improve global fiber CSA and fiber-type specific CSA. However, a significant treatment effect was observed for capillary density (P = 0.0445), with increases observed for both SedV (P = 0.034) and EnV (P = 0.0117). Conclusion: EVs isolated from plasma after exercise can significantly improve skeletal muscle vascularization after immobilization, which may represent an important step toward full recovery of skeletal muscle mass. Partially support by NIH (NIAMS R01AR072735). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Late-life aerobic exercise reverses DNA damage and telomere dysfunction in non-atheroprone aortic regions with advanced age

Cellular senescence, a state of cell cycle arrest, contributes to arterial aging. The dominant factor driving cellular senescence is DNA damage. Moreover, telomeres, a repeated DNA sequence at the end of chromosomes, are especially vulnerable to DNA damage induced by DNA-damaging stimuli such as atheroprone shear stress. Although the adoption of aerobic exercise in later life is an effective strategy to mitigate arterial aging, its direct relationship with DNA damage and telomere dysfunction has yet to be elucidated. Additionally, the impact of late-life aerobic exercise, particularly in regions exposed to atheroprone and non-atheroprone shear stress, may not yield uniform benefits, requiring further exploration. We sought to investigate the effects of late-life aerobic exercise on DNA damage and telomere dysfunction in endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) in aortic regions exposed to distinct shear stress patterns such as the major aortic arch, minor aortic arch, and thoracic aorta. Fifteen male C57BL6 (22-23 mo) were given access to voluntary running wheel (VWR) for 4 weeks. They were classified as high-running (HR), moderate-running (MR), and low-running (LR) groups based on their habitual VWR distances (n=5 per group). Habitual VWR distance was greater in HR and MR compared to LR (75.9±11.2 and 21.3±1.6 vs. 5.8±2 m/day; P≤0.0003). Maximal treadmill running distance improved in HR, did not change in MR, and diminished in the LR (HR, MR vs. LR; P≤0.035) and was correlated to habitual VWR distance at 1-month post-intervention (R2=0.252, P=0.056). Immunofluorescence-fluorescent in situ hybridization was performed to detect the abundance of 53BP1 foci, a marker of DNA damage, and colocalization to telomeres, a measure of telomere-specific DNA damage known as telomere dysfunction-induced foci (TIF). The percentage of ECs containing 53BP1 foci and TIF was lower in the non-atheroprone aortic regions, i.e. major aortic arch and thoracic aorta, of HR compared to LR (P≤0.002), but there was no difference in the atheroprone, i.e. minor aortic arch (P≥0.899). A strong to moderate correlation was observed between 53BP1 foci and habitual VWR distance in major aortic arch and thoracic aorta (R2=0.584 and R2=0.54, P≤0.002) but only between VWR and TIF in the thoracic aorta (R2=0.356, P=0.019). The 53BP1 foci and TIF in VSMCs were comparable across groups in all aortic regions (P≥0.102). Likewise, Telomere length in ECs and VSMCs were similar across groups regardless of aortic region (P≥0.296). In conclusion, our findings suggest that increased level of habitual aerobic exercise in later life has a beneficial impact on DNA damage and telomere dysfunction in ECs, particularly in aortic regions exposed to extended periods of non-atheroprone shear stress. Notably, the volume of aerobic exercise was inversely associated with DNA damage and telomere dysfunction. These effects were independent of telomere length. The improvement in DNA damage and telomere dysfunction associated with habitual aerobic exercise were specific to ECs, as VSMCs remained unaffected in all aortic regions and results were independent of telomere length. Funded in part by awards from National Institutes of Health Awards R01 AG060395, R01 AG077751, R01 AG076748, T32 HL007576, T32 HL139451, Veteran's Affairs Merit Review Award I01 BX004492 and Nora Eccles Treadwell Foundation. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Mitochondrial antioxidant elamipretide improves learning and memory impairment induced by chronic sleep deprivation in mice.

The inflammation and synaptic dysfunction induced by mitochondrial dysfunction play essential roles in the learning and memory impairment associated with sleep dysfunction. Elamipretide (SS-31), a novel mitochondrion-targeted antioxidant, was proven to improve mitochondrial dysfunction, the inflammatory response, synaptic dysfunction, and cognitive impairment in models of cerebral ischemia, sepsis, and type 2 diabetes. However, the potential for SS-31 to improve the cognitive impairment induced by chronic sleep deprivation (CSD) and its underlying mechanisms is unknown. Adult c57BL/6J mice were subjected to CSD for 21 days using an activity wheel accompanied by daily intraperitoneal injection of SS-31 (5mg/kg). The novel object recognition and Morris water maze test were used to evaluate hippocampus-dependent cognitive function. Western blotting and reverse transcription-quantitative polymerase chain reaction assays were used to determine the effects of CSD and SS-31 on markers of mitochondria, inflammation response, and synaptic function. Enzyme-linked immunosorbent assays were used to examine the levels of proinflammatory cytokines. SS-31 could improve the cognitive impairment induced by CSD. In particular, SS-31 treatment restored the CSD-induced decrease in sirtuin 1 (SIRT1) and peroxisome proliferator-activated receptor γ coactivator alpha levels and the increase in levels nuclear factor kappa-B and inflammatory cytokines, including interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha. Furthermore, SS-31 significantly increased the levels of brain-derived neurotrophic factor, postsynaptic density protein-95, and synaptophysin in CSD mice. Taken together, these results suggest that SS-31 could improve CSD-induced mitochondrial biogenesis dysfunction, inflammatory response, synaptic dysfunction, and cognitive impairment by increasing SIRT1 expression levels.

Voluntary wheel running reduces tumor growth and increases capillarity in the heart during doxorubicin chemotherapy in a murine model of breast cancer.

Introduction: The possible beneficial effects of physical activity during doxorubicin treatment of breast cancer need further investigation as many of the existing studies have been done on non-tumor-bearing models. Therefore, in this study, we aim to assess whether short-term voluntary wheel-running exercise during doxorubicin treatment of breast cancer-bearing mice could induce beneficial cardiac effects and enhance chemotherapy efficacy. Methods: Murine breast cancer I3TC cells were inoculated subcutaneously to the flank of female FVB mice (n = 16) that were divided into exercised and non-exercised groups. Two weeks later, doxorubicin treatment was started via intraperitoneal administration (5mg/kg weekly for 3weeks). Organs were harvested a day after the last dose. Results: The tumor volume over time was significantly different between the groups, with the exercising group having lower tumor volumes. The exercised group had increased body weight gain, tumor apoptosis, capillaries per cardiomyocytes, and cardiac lactate dehydrogenase activity compared to the unexercised group, but tumor blood vessel density and maturation and tumor and cardiac HIF1-α and VEGF-A levels did not differ from those of the non-exercised group. Discussion: We conclude that even short-term light exercise such as voluntary wheel running exercise can decrease the subcutaneous mammary tumor growth, possibly via increased tumor apoptosis. The increase in cardiac capillaries per cardiomyocytes may also have positive effects on cancer treatment outcomes.

Endocannabinoid remodeling in murine cachexic muscle associates with catabolic and metabolic regulation

Muscle degeneration is a common feature in cancer cachexia that cannot be reversed. Recent advances show that the endocannabinoid system, and more particularly cannabinoid receptor 1 (CB1), regulates muscle processes, including metabolism, anabolism and regenerative capacity. However, it is unclear whether muscle endocannabinoids, their receptors and enzymes are responsive to cachexia and exercise. Therefore, this study investigated whether cachexia and exercise affected muscle endocannabinoid signaling, and whether CB1 expression correlated with markers of muscle anabolism, catabolism and metabolism. Male BALB/c mice were injected with PBS (CON) or C26 colon carcinoma cells (C26) and had access to wheel running (VWR) or remained sedentary (n = 5–6/group). Mice were sacrificed 18 days upon PBS/tumor cell injection. Cachexic mice exhibited a lower muscle CB1 expression (−43 %; p < 0.001) and lower levels of the endocannabinoid anandamide (AEA; −22 %; p = 0.044), as well as a lower expression of the AEA-synthesizing enzyme NAPE-PLD (−37 %; p < 0.001), whereas the expression of the AEA degrading enzyme FAAH was higher (+160 %; p < 0.001). The 2-AG-degrading enzyme MAGL, was lower in cachexic muscle (−34 %; p = 0.007), but 2-AG and its synthetizing enzyme DAGLβ were not different between CON and C26. VWR increased muscle CB1 (+25 %; p = 0.005) and increased MAGL expression (+30 %; p = 0.035). CB1 expression correlated with muscle mass, markers of metabolism (e.g. p-AMPK, PGC1α) and of catabolism (e.g. p-FOXO, LC3b, Atg5). Our findings depict an emerging role of the endocannabinoid system in muscle physiology. Future studies should elaborate how this translates into potential therapies to combat cancer cachexia, and other degenerative conditions.

Osterix-driven LINC complex disruption in vivo diminishes osteogenesis at 8 weeksbut not at 15 weeks.

The Linker of Nucleoskeleton and Cytoskeleton (LINC) complex is a crucial connective component between the nuclear envelope and the cytoskeleton involving various cellular processes including nuclear positioning, nuclear architecture, and mechanotransduction. How LINC complexes regulate bone formation in vivo, however, is not well understood. To start bridging this gap, here we created a LINC disruption murine model using transgenic mice expressing Cre recombinase enzyme under the control of the Osterix (Osx-Cre) which is primarily active in pre-osteoblasts and floxed Tg(CAG-LacZ/EGFP-KASH2) mice. Tg(CAG-LacZ/EGFP-KASH2) mice contain a lox-STOP-lox flanked LacZ gene which is deleted upon cre recombination allowing for the overexpression of an EGFP-KASH2 fusion protein. This overexpressed protein disrupts endogenous Nesprin-Sun binding leading to disruption of LINC complexes. Thus, crossing these two lines results in an Osx- driven LINC disruption (ODLD) specific to pre-osteoblasts. In this study, we investigated how this LINC disruption affects exercise-induced bone accrual. ODLD cells had decreased osteogenic and adipogenic potential in vitro compared to non-disrupted controls and sedentary ODLD mice showed decreased bone quality at 8 weeks. Upon access to a voluntary running wheel,ODLD animals showed increased running time and distance; however, our 6-week exercise intervention did not significantly affect bone microarchitecture and bone mechanical properties.

Voluntary Wheel Running Reduces Cardiometabolic Risks in Female Offspring Exposed to Lifelong High-Fat, High-Sucrose Diet.

Maternal and postnatal overnutrition has been linked to an increased risk of cardiometabolic diseases in offspring. This study investigated the impact of adult-onset voluntary wheel running to counteract cardiometabolic risks in female offspring exposed to a life-long high-fat, high-sucrose (HFHS) diet. Dams were fed either an HFHS or a low-fat, low-sucrose (LFLS) diet starting from 8 wk before pregnancy and continuing throughout gestation and lactation. Offspring followed their mothers' diets. At 15 wk of age, they were divided into sedentary (Sed) or voluntary wheel running (Ex) groups, resulting in four groups: LFLS/Sed ( n = 10), LFLS/Ex ( n = 5), HFHS/Sed ( n = 6), HFHS/Ex ( n = 5). Cardiac function was assessed at 25 wk, with tissue collection at 26 wk for mitochondrial respiratory function and protein analysis. Data were analyzed using two-way ANOVA. Although maternal HFHS diet did not affect the offspring's body weight at weaning, continuous HFHS feeding postweaning resulted in increased body weight and adiposity, irrespective of the exercise regimen. HFHS/Sed offspring showed increased left ventricular wall thickness and elevated expression of enzymes involved in fatty acid transport (CD36, FABP3), lipogenesis (DGAT), glucose transport (GLUT4), oxidative stress (protein carbonyls, nitrotyrosine), and early senescence markers (p16, p21). Their cardiac mitochondria displayed lower oxidative phosphorylation (OXPHOS) efficiency and reduced expression of OXPHOS complexes and fatty acid metabolism enzymes (ACSL5, CPT1B). However, HFHS/Ex offspring mitigated these effects, aligning more with LFLS/Sed offspring. Adult-onset voluntary wheel running effectively counteracts the detrimental cardiac effects of a lifelong HFHS diet, improving mitochondrial efficiency, reducing oxidative stress, and preventing early senescence. This underscores the significant role of physical activity in mitigating diet-induced cardiometabolic risks.

Swimming Exercise Protocol and Care Methods for Pregnant Rats.

The developmental origins of health and disease concept highlights the impact of early environments on chronic non-communicable diseases like diabetes, cardiovascular disease, and cancer. Studies using animal models have investigated how maternal factors such as undernutrition, overnutrition, obesity, and exposure to chemicals or hypoxia affect fetal development and offspring health, leading to issues like low birth weight, high blood pressure, dyslipidemia, and insulin resistance. Given the increasing prevalence of overweight and obesity among reproductive-age women, effective interventions are critical. Maternal exercise during pregnancy has emerged as a key intervention, benefiting both mother and offspring and reducing the risk of disease. This study compares the differences of three exercise models on pregnant rats: voluntary wheel running, motorized treadmills, and swimming. Swimming is the most beneficial option due to its safe and controlled intensity levels. This protocol details the rat breeding methods, swimming training during pregnancy, and post-breeding nursing protocols. This model, suitable for various rat and mouse species, is useful for studying the benefits of maternal exercise on offspring health and intergenerational wellness.

Subcutaneous hydromorphone hydrochloride provides antinociception with transient adverse effects in four-toed hedgehogs (Atelerix albiventris).

To evaluate the efficacy and safety of hydromorphone administered SC in four-toed hedgehogs (Atelerix albiventris). 12 healthy adult hedgehogs. Hedgehogs underwent 2 randomized, blinded, placebo-controlled, complete crossover studies. Hind limb withdrawal latencies in response to an acute thermal noxious stimulus were measured to evaluate the antinociceptive efficacy of hydromorphone. Baseline latencies were obtained prior to injection and collected again at 0.5, 1, 2, 4, and 6 hours following injection. Based on pilot studies, single doses of SC hydromorphone at 0.15 and 0.3 mg/kg were evaluated for efficacy in crossover trials. Safety of single (0.15 and 0.3 mg/kg) and multiple doses of hydromorphone (0.3 mg/kg, SC, q 4 h, for 3 doses) was also assessed. In addition to monitoring behavior during latency measurements, animals were evaluated for overt sedation and daily changes in food intake, body weight, and running wheel activity for 6 days after injection to evaluate for adverse effects. Hydromorphone at 0.15 mg/kg provided antinociception lasting < 4 hours, and 0.3 mg/kg provided antinociception lasting < 6 hours. Hydromorphone produced transient abnormal behaviors at both doses, including vocalization, chewing motions of the jaw, and paw raising. There were no statistically significant differences in body weight or running wheel activity between treatments for single or multiple doses of hydromorphone. Three doses of 0.3 mg/kg hydromorphone (q 4 h) produced a statistically significant decrease (median, -9.7%; range, -64% to 10%) in 6-day total food intake. Subcutaneous hydromorphone (0.15 to 0.3 mg/kg) can be used for short-term antinociception with transient adverse effects in hedgehogs.

Analysis of Ergonomic Factor Measurement for Transjakarta Bus Drivers

Transjakarta transportation accidents have increased from year to year. Transjakarta buses having an accident can result in the driver not feeling comfortable while driving so that the driver experiences a lack of concentration. Therefore, the authors conducted a study that aimed to investigate the ergonomic factors experienced by Transjakarta bus drivers. The author uses the Rapid Upper Limb Assessment (RULA) method by taking 30 Transjakarta bus driver data and by using the Nordic Body Map (NBM) method by taking 30 driver data using a questionnaire. The results of the RULA method have been used to test the correlation using the Minitab software. The results of the RULA on reaching the steering wheel activity were 3-4 which means that further investigation was needed and may require changes to improve. And for the average time to reach the button was 5-6 which means the need for immediate investigation and change. NBM results show that most of them experience pain in the waist so that it is necessary to improve the position of the waist. Correlation Test Results The activity of reaching the button and the activity of reaching the steering wheel is -0.209 and the P-Value is 0.268 so that the results of an inverse relationship between the activity of reaching the steering wheel and reaching the button are found. The greater the activity reaches the wheel, the smaller the activity reaches the button. The correlation found has a very weak relationship between variables.

Alleviative effects of the parthenolide derivative ACT001 on insulin resistance induced by sodium propionate combined with a high-fat diet and its potential mechanisms

The increasing side effects of traditional medications used to treat type II diabetes have made research into the development of safer and more effective natural medications necessary. ACT001, a derivative of parthenolide, has been shown to have good anti-inflammatory and antitumor effects; however, its role in diabetes is unclear. The short-chain fatty acid propionate is a common food preservative that has been found to cause disturbances in glucose metabolism in mice and humans. This study aimed to investigate whether sodium propionate could aggravate insulin resistance in obese mice and cause diabetes and to study the alleviative effects and potential mechanisms of action of ACT001 on insulin resistance in diabetic mice. Type II diabetic mice were adminietered sodium propionate combined with a high-fat diet (HFD + propionate) by gavage daily for four weeks. Biochemical analysis showed that ACT001 significantly affected blood glucose concentration in diabetic mice, mainly by downregulating the expression of phosphoenolpyruvate carboxykinase 2 and glucose-6-phosphatase. Meanwhile, the level of fatty acid-binding protein 4 in the liver was significantly decreased. ACT001 has a protective effect on the liver and adipose tissue of mice. In addition, the results of the running wheel experiment indicated that ACT001 alleviated the circadian rhythm disorder caused by insulin resistance to a certain extent. This study revealed the potential mechanism by which ACT001 alleviates insulin resistance and provides ideas for developing natural antidiabetic drugs.

A Murine Model of Hyperlipidemia-Induced Heart Failure with Preserved Ejection Fraction.

The pathophysiology of heart failure with preserved ejection fraction (HFpEF) driven by lipotoxicity is incompletely understood. Given the urgent need for animal models that accurately mimic cardio-metabolic HFpEF, a hyperlipidemia-induced murine model was developed by reverse engineering phenotypes seen in HFpEF patients. This model aimed to investigate HFpEF, focusing on the interplay between lipotoxicity and metabolic syndrome. Hyperlipidemia was induced in wild-type (WT) mice on a 129J strain background through bi-weekly intraperitoneal injections of poloxamer-407 (P-407), a block co-polymer that blocks lipoprotein lipase, combined with a single intravenous injection of adeno-associated virus 9-cardiac troponin T-low-density lipoprotein receptor (AAV9-cTnT-LDLR). Extensive assessments were conducted between 4 and 8 weeks post-treatment, including echocardiography, blood pressure recording, whole-body plethysmography, echocardiography (ECG) telemetry, activity wheel monitoring (AWM), and biochemical and histological analyses. The LDLR/P-407 mice exhibited distinctive features at four weeks, including diastolic dysfunction, preserved ejection fraction, and increased left ventricular wall thickness. Notably, blood pressure and renal function remained within normal ranges. Additionally, ECG and AWM revealed heart blocks and reduced activity, respectively. Diastolic function deteriorated at eight weeks, accompanied by a significant decline in respiratory rates. Further investigation into the double treatment model revealed elevated fibrosis, wet/dry lung ratios, and heart weight/body weight ratios. The LDLR/P-407 mice exhibited xanthelasmas, ascites, and cardiac ischemia. Interestingly, sudden deaths occurred between 6 and 12 weeks post-treatment. The murine HFpEF model offers a valuable and promising experimental resource for elucidating the intricacies of metabolic syndrome contributing to diastolic dysfunction within the context of lipotoxicity-mediated HFpEF.

ТЕОРЕТИЧЕСКОЕ ОБОСНОВАНИЕ ТРАНСПОРТЕРА ДЛЯ ВЫГРУЗКИ КОРНЕПЛОДОВ ОВОЩНЫХ КУЛЬТУР И КЛУБНЕЙ КАРТОФЕЛЯ ИЗ ХРАНИЛИЩА

The need to develop specialized machines and equipment for laboratory and field research on potato breeding is due to the fact that the methodology of breeding processes and the first stages of seed production involves comparing many plants of different origins and selecting the best for further work up to the creation of a new variety or transfer of seeds for propagation in production conditions. The large variability of machines for unloading vegetables and potatoes does not adequately prevent damage to vegetable and potato products, which is due to the imperfect design of such machines, including the imperfection or absence of patterns of automated control of the technological process of work and justification of the parameters of their working parts. The purpose of the study is to substantiate the parameters of the conveyor for unloading vegetable crops and potatoes into storage and to determine the patterns of formation of the control signal of the transfer function of automatic control of operation. The power required to move the pick-up depends on the maximum pressure force of introducing the intake element into the embankment, the mass of the pick-up and the rolling resistance coefficients of the running wheels of the pick-up and transport sections. The length of the unloading conveyor of the machine is determined by the reserve zone to prevent wheels from hitting the tubers, their maximum difference in the embankment, the height of the layer, as well as the angle of inclination of the unloading conveyor. The width of the conveyor belt for unloading products from storage is determined by the values of the coefficient of friction of root crops on the surface of the belt, the coefficient of working time utilization and the forward speed of the conveyor belt. After removing the collapsed mass of tubers, the line of crumbling slopes and the limiting equilibrium are a straight line, characterized by an empirical equation for determining the coordinates of the tuber collapse point, the height of the tuber layer and the embankment collapse coefficient. When the feeder tubers are introduced into the surface of the embankment, the formation of slopes occurs in four stages: the formation of a natural slope, a limiting equilibrium slope, a shedding slope and a product collapse slope.

Differential effects of voluntary exercise and housing density on anxiety-like behavior in C57Bl/6 mice

The interaction of voluntary exercise and housing density on a) anxiety-like behavior and b) the stimulant effects of methamphetamine in C57Bl/6 mice were evaluated. Upon arrival, mice were housed singly or in pairs, and permitted access to home-cage running wheels or not for 4 weeks. Testing for anxiety-like behavior occurred over the next 3 weeks, one test per week [Elevated-Plus Maze (EPM) → Hyponeophagia (HNP) task → Open-Field (OF) task]. The final, OF task involved an 8-hour session in which mice were permitted to explore the chamber (drug free) during Hours 1–3; given an injection (s.c.) of methamphetamine (1.0 mg/kg) after Hour 3; followed by continued behavioral sampling during Hours 4–8. Several tasks (HNP and OF, but not EPM) consistently showed voluntary exercise induced anxiety-like behavior. In addition, two measures (time in center and time resting in the perimeter) in the OF task revealed that exercise mice compared to controls were more responsive to the anxiogenic effects of methamphetamine. Although pair housing was anxiolytic, it did not ameliorate the anxiogenic effects of voluntary exercise. Taken together, these results, when viewed in tandem with previous studies that utilized a less anxious mouse strain (Swiss Webster), may suggest that voluntary exercise is anxiogenic in an anxiety-prone mouse strain such as C57Bl/6 and highlight the importance of considering mouse strain when evaluating the impact of environmental manipulations on anxiety-like behavior in animal models.

Voluntary exercise preserves visual function and reduces inflammatory response in an adult mouse model of autosomal dominant retinitis pigmentosa

Whole-body physical exercise has been shown to promote retinal structure and function preservation in animal models of retinal degeneration. It is currently unknown how exercise modulates retinal inflammatory responses. In this study, we investigated cytokine alterations associated with retinal neuroprotection induced by voluntary running wheel exercise in a retinal degeneration mouse model of class B1 autosomal dominant retinitis pigmentosa, I307N Rho. I307N Rho mice undergo rod photoreceptor degeneration when exposed to bright light (induced). Our data show, active induced mice exhibited significant preservation of retinal and visual function compared to inactive induced mice after 4 weeks of exercise. Retinal cytokine expression revealed significant reductions of proinflammatory chemokines, keratinocyte-derived chemokine (KC) and interferon gamma inducible protein-10 (IP-10) expression in active groups compared to inactive groups. Through immunofluorescence, we found KC and IP-10 labeling localized to retinal vasculature marker, collagen IV. These data show that whole-body exercise lowers specific retinal cytokine expression associated with retinal vasculature. Future studies should determine whether suppression of inflammatory responses is requisite for exercise-induced retinal protection.

Influence of sex and sedentary conditions on sympathetic burst characteristics in prepubertal, postpubertal, and young adult rats.

Recent evidence indicates that sex-based differences in cardiovascular disease (CVD) begin early in life, particularly when associated with risk factors such as a sedentary lifestyle. CVD is associated with elevated sympathetic nerve activity (SNA), quantified as increased SNA burst activity in humans. Whether burst characteristics are influenced by sex or sedentary conditions at younger ages is unknown. The purpose of our study is to compare SNA bursts in active and sedentary female and male rats at ages including prepuberty and young adulthood. We hypothesized that burst characteristics and blood pressure are higher under sedentary conditions and lower in female rats compared with males. We analyzed splanchnic SNA (SpSNA) recordings from Inactin-anesthetized male and female rats at 4-, 8-, and 16-wk of age. Physically active and sedentary rats were each housed in separate, environmentally controlled chambers where physically active rats had free access to an in-cage running wheel. Sympathetic bursts were obtained by rectifying and integrating the raw SpSNA signal. Burst frequency, burst height, and burst width were calculated using the Peak Parameters extension in LabChart. Our results showed that sedentary conditions produced a greater burst width in 8- and 16-wk-old rats compared with 4-wk-old rats in both males and females (P < 0.001 for both). Burst frequency and incidence were both higher in 16-wk-old males compared with 16-wk-old females (P < 0.001 for both). Our results suggest that there are sedentary lifestyle- and sex-related mechanisms that impact sympathetic regulation of blood pressure at ages that range from prepuberty into young adulthood.NEW & NOTEWORTHY The mechanisms of decreased incidence of cardiovascular disease (CVD) in reproductive-age women compared with age-matched men are unknown. The strong association between elevated sympathetic activity and CVD led us to characterize splanchnic sympathetic bursts in female and male rats. Prepubescent males and females exhibited narrower sympathetic bursts, whereas young adult males had higher resting burst frequency compared with age-matched females. Sex-based regulation of sympathetic activity suggests a need for sex-dependent therapeutic strategies to combat CVD.