Hind Leg Muscle Research Articles

Correlation Between Hyperlipidemia-Related Diseases and Thorax/Thigh Circumference Ratio Along with Body Condition Score in Dogs Focusing on Molecular Mechanism: A Pilot Study and Literature Review.

There are some limitations to using the body condition score (BCS) for client education to prevent obesity, hyperlipidemia-related diseases, and orthopedic diseases in dogs because it is hard to quantify in detail. Especially in small dogs, patellar luxation is a common orthopedic disease that is related to obesity and the hind leg muscle. In this pilot study, the author evaluated the thorax/thigh circumference ratio as a prognostic evaluation index, along with the BCS, for assessing patellar dislocation and other hyperlipidemia-related diseases and states such as hypertriglyceridemia and obesity-related orthopedic disease in small dogs. Eleven client-owned dogs were selected randomly among patients that visited Bundang New York Animal Hospital, South Korea from June 2021 to August 2024. According to the results, triglycerides (TG) showed a negative correlation with thorax/thigh value (R = -0.585, p-value = 0.059) and a strong positive correlation with thigh circumference (R = 0.749, p-value = 0.008). Total cholesterol (TC) showed a strong positive correlation with thigh circumference (R = 0.776, p-value = 0.005), whereas the thorax/thigh value showed a negative correlation with the medial patella luxation (MPL) grade with low significance (R = -0.343, p-value = 0.302). These data indicate that thigh circumference can be an excellent negative indicator for hyperlipidemia and thorax/thigh value shows no correlation with medial patella luxation, which has many factors such as varus and trochlear groove. Despite the limitations of this study due to the small sample size, this pilot study is significant as it is the first trial to introduce a new indicator for monitoring hyperlipidemia at home by using a simple tape measure. Also, the author reviews molecular pathways including the ApoA-1, ApoE, and LPL genes, which are related to hyperlipidemia, to explain the results.

Genome wide association studies for carcass traits measured by video image analysis in crossbred lambs

This is the first UK genome wide association study investigating potential links between Video Image Analysis (VIA) carcass traits and molecular polymorphisms in crossbred sheep. Phenotypic and genotypic data were collected from two crossbred lamb populations: Texel x Scotch Mule (TxSM, n = 2330) and Texel x Lleyn (TxL, n = 3816). Traits measured included live weights at birth, eight weeks and weaning (∼15 weeks). VIA-predicted traits included total weights and weights of fat, muscle and bone in the whole carcass and primal (hind leg, saddle, shoulder) regions. Within-breed heritabilities estimated for the VIA traits ranged from 0.01 to 0.70, indicating potential for inclusion of some traits in breeding programmes. The two crossbred populations differed in SNPs associated with different traits. Two SNPs on chromosomes two (s74618.1) and eight (s68536.1), respectively, reached genome-wise significance for TxSM, explaining <1% of trait variance, for whole carcass fat and muscle weights, hind leg and saddle fat weights and shoulder bone weights. For TxL, four SNPs reached genome-wise significance, on chromosome two for hind leg muscle weight (OAR2_117,959,202 and OAR2_11804335), on chromosome 10 for whole carcass bone weight (OAR19_8,995,957.1), and on chromosome 19 for weaning weight (s40847.1), each explaining <1% of trait genetic variation. Differences in apparent genetic control of carcass traits may be influenced by the lambs' cross-breed, but also by management decisions affecting environmental variance and trait definitions, which should be understood in order to define protocols for incorporation of carcass traits into (cross)breeding programmes. ImplicationsCombining VIA-measured carcass traits with conventional production traits in a breeding programme could potentially improve the production and product quality of meat sheep. Phenotypes for VIA traits could be collected relatively easily if VIA machines were present at all abattoir sites. The current study and future Genome Wide Association Studies may help to identify potentially informative molecular markers, that explain large proportions of the genetic variance observed in VIA-measured carcass traits. Including this information in the estimation of breeding values could increase the accuracy of prediction, increasing the potential rate of genetic improvement for product quality. This study confirms the polygenic architecture of the investigated carcass traits, with a small number of molecular markers that each explain a small amount of genetic variation. Further studies across breed types are recommended to further test and validate molecular markers for traits related to lamb carcass quality, as measured by video image analysis.

A histological examination of the effects of Ferula elaeochytris extract on kidney and liver tissues in myoglobinuric acute renal failure

ABSTRACT Myoglobinuric acute renal failure (MARF) is a structural and functional disorder that occurs in the kidney following the release of muscle cell contents into the circulation. In this present study, possible protective and curative effects of Ferula elaeochytris extract against kidney and liver damage in experimentally induced MARF in a rat model were investigated. 3–4 Month-old, 200–250 g Sprague Dawley rats were divided into 8 equal groups with 7 rats per group. Group I was a no-intervention Control group. All groups except for the Group I were dehydrated for 16 hours. Following this dehydration, 50% v/v aqueous glycerol solution was injected into both hind leg muscles of the animals, at a dose of 8 ml/kg. The rats were given physiological saline (SF) once orally before the model was administered (Group II) and after the model was administered (Group V). Similarly, two different doses of Ferula elaeochytris root extract (40 mg/kg and 80 mg/kg) were dissolved in 2 ml of SF and administered orally before (Groups III and IV) and after (Group VI, VII) the model was created. Following the experimental period, kidney and liver tissues were removed from all groups, and fixed in 10% neutral formaldehyde solution for light microscopic examinations. Intracellular vacuolization, enlargement in the Bowman’s space, widespread atrophy in the tubular structures, luminal enlargement, and desquamation were detected in the kidney tissue sections of all the experimental model groups. In the liver tissue sections, was detected hepatocyte degeneration, intracellular vacuolization, irregularity in cell membrane borders, and apoptotic bodies. These histopathological consequences of MARF were evaluated for all groups, and whereas a curative effect of Ferula elaeochytris could be seen, its protective effect was higher than its curative effect.

Characterisation of the myosin light chain kinase (MLCK) gene of Locusta migratoria and the encoded MLCK.

Myosin light chain kinase (MLCK) is a dedicated kinase of myosin regulatory light chain (RLC), playing an essential role in the regulation of muscle contraction and cell motility. Much of the knowledge about MLCK comes from the study of vertebrate MLCK, and little is known about insect MLCK. Here, we identified the single MLCK gene in the locust Locusta migratoria, which spans over 1400 kb, includes 62 exons and accounts for at least five transcripts. We found that the five distinct transcripts of the locust MLCK gene are expressed in a tissue-specific manner, including three muscle-specific isoforms and two generic isoforms. To characterise the kinase activity of locust MLCK, we recombinantly expressed LmMLCK-G, the smallest locust MLCK isoform, in insect Sf9 cells. We demonstrated that LmMLCK-G is a Ca2+/calmodulin-dependent kinase that specifically phosphorylates serine 50 of locust muscle myosin RLC (LmRLC). Additionally, we found that almost all LmRLC molecules in the flight muscle and the hindleg muscles of adult locusts are phosphorylated.

Investigation of heavy metals in tissues and habitats of three edible frogs from Türkiye.

The soil, water, and organisms have been contaminated by heavy metals due to human activities and industrialization, which has produced a major environmental problem that has a deleterious effect on human health and food quality. Frogs, one of the good bioindicators for environmental pollution, are also among the alternative essential protein sources for humans. In Türkiye, three of these frogs are edible: Pelophylax ridibundus, Pelophylax bedriagae, and Pelophylax caralitanus, also known as Anatolian water frogs. Hence, to assess the possible health risks that might result from consuming frog legs in addition aquatic habitat of Anatolian water frogs, the water, sediment, and frog tissue samples (muscle and liver) were obtained from 11 different provinces covering all regions of Türkiye and analyzed to determine Cd, Cu, Cr, Zn, Pb, and As concentrations. The results revealed considerable variations in heavy metal concentrations among frog tissues, influenced by the sampling sites and species (ANOVA: p < 0.05). The Estimated Daily Intake (EDI) values, calculated based on the average serving size, were also lower than the Provisional Tolerable Daily Intake (PTDI) levels for adult consumers. Furthermore, the study computed the Target Hazard Quotient (THQ) values for heavy metals, all of which were below the critical value of 1, indicating that consuming the hind leg muscles from these frog species would not pose an adverse health risk for humans.

Effect of Gender and Muscle Type on Fatty Acid Profile, Sanogenic Indices, and Instrumental and Sensory Analysis of Flemish Giant Rabbit Meat

The aim of this study was to represent quality characterization, by gender and muscle type, of rabbit meat from the Flemish Giant (FG) breed, following the fatty acid profile, sanogenic indices, and instrumental (color and texture) and sensory analysis. The biological material comprised 40 rabbits (20 females and 20 males) whose Longissimus dorsi (LD) and Semimembranosus (SM) muscles were sampled. Compared to female samples, the meat from males was more qualitative in terms of higher ratios of polyunsaturated vs. saturated fatty acids and proportions (+42%) of Essential and Desirable Fatty Acids (+21.6% EFA; +6.7% DFA). Also, the Atherogenic Index (AI) and Thrombogenic Index (TI) were better in males (−37.1% AI; −34.3% TI), as were the ratio of hypocholesterolemic/Hypercholesterolemic fatty acids (+27.8%) and the Nutritive Value Index (NVI, +11.6%). The Polyunsaturation Index (PI) was higher for females (+57.5%), with the widest differences in hind leg muscles (SM muscles), while the omega-6/omega-3 fatty acid ratio was also better (+11.3%). Female meat was more tender due to lower shear force (−6.2%… 9.3%) in both muscles. Female meat was less pigmented than that of males, while the overall sensory attributes were better scored in male samples (+3.1%… +7.1%) (p &lt; 0.01). The meat of males proved to be more sanogenic (richer in EFA and DFA, with a better h/H ratio and NVI, while AI and TI were lower). We would recommend slaughtering 3–4 weeks earlier in females vs. males to avoid excessive fat deposition and, consequently, the development of unfavorable sanogenic indices for consumer health.

Sensory Evaluation of Rabbit Meat from Individuals Fed Functional and More Sustainable Diets Enriched with Freshwater Cladophora glomerata Macroalgal Biomass.

Maintaining meat quality is essential to sustainable livestock management. Therefore, identifying alternative feed materials while considering consumer acceptance is crucial. So, the aim of this study was to evaluate the effect of C. glomerata-biomass-supplemented feeds on rabbit muscles' physical properties, sensory profiles, and evaluators' emotional responses to them. A total of thirty 52-day-old weaned Californian breed rabbits were randomly allocated to one of three dietary treatments: standard compound diet (SCD), SCD supplemented with 4% C. glomerata (CG4), or SCD supplemented with 8% C. glomerata (CG8). After the 122-day-old rabbits were slaughtered, post-mortem dissection of the rabbit Longissimus dorsi (LD) and hind leg (HL) muscles was conducted. The physical and histomorphometric features, sensory analyses, and emotional responses to the rabbit's muscles were determined. Study results revealed CG4 and CG8 treatments significantly increased rabbit muscle moisture, while CG8 increased cooking losses in HL muscles (p < 0.05). Moreover, both CG treatments reduced the darkness and redness of fresh and cooked rabbit muscles compared to SCD (p < 0.05). CG8 treatment compared to SCD resulted in longer LD muscle fibers (p < 0.05). Evaluators discovered that the average scores for each sensory description of rabbit meat are acceptable and that consuming CG8-HL muscles can increase happiness based on emotional responses. Consequently, replacing traditional feed materials in rabbit feed with C. glomerata can lead to not only more sustainable production but also more consumer-acceptable rabbit meat.

Abstract 6716: Preclinical evaluation of nano-liposomal irinotecan in pediatric solid tumor patient-derived xenografts

Abstract Background: Pediatric solid tumors are rare and the use of well characterized preclinical models can be a helpful tool to prioritize novel drug combinations and formulations which are challenging to test in a limited patient population. Irinotecan (IRN) has shown efficacy in diverse pediatric cancers where children are often treated on an extended low-dose schedule rather than a single large dose commonly used in adults. The use of nano-liposomal irinotecan (nal-IRI) is a promising strategy as 95% of the drug remains encapsulated during systemic exposure while maintaining prolonged exposure in the tumor. Adult clinical trials have shown reduced side effects without compromising efficacy but nal-IRI has had limited use thus far in pediatric cancers. Methods: Orthotopic xenograft models of Ewing sarcoma (EWS, 4 models) and rhabdomyosarcoma (RMS, 2 models) were generated by injecting luciferase labeled cells into the femur and hind-leg muscle of nude mice respectively. Pharmacokinetic (PK) studies on normal and tumor-bearing mice were performed for both nal-IRI and standard IRN to determine matched human AUC-guided dosing and schedule of chemotherapy agents. Mice were randomized to single agent and relevant combinations of nal-IRI with PARP inhibitors and temozolomide (EWS) and with vincristine and temozolomide (RMS) and compared to the same regimens using standard IRN. Therapy was given on a clinically relevant schedule with each course consisting of 21 days and tumor response was measured weekly using bioluminescence. Results: PK studies showed that plasma levels of the active metabolite of IRN (SN-38) drop quickly for both standard IRN and nal-IRI single dosed mice while the levels of SN-38 were maintained in the tumor for several days using the nal-IRI formulation. In all 6 models tested, nal-IRI combinations were as or more effective when compared to regimens using standard IRN. No significant toxicity was seen in mice treated with nal-IRI combinations. Conclusions: The substitution of nal-IRI for standard IRN remains a promising strategy in pediatrics with the potential to reduce side effects as well as hospital visits due to the dosing schedule with nal-IRI given once per cycle where standard IRN is often given for 5 or 10 days in children. Our preclinical PK data confirmed the liposomal formulation resulted in sustained SN-38 levels in the tumor and efficacy was maintained or improved in pediatric cancer models. The combination of nal-IRI with temozolomide and talazoparib is now being tested in a multi-center randomized phase I/II trial for children with relapsed solid tumors and this data supports consideration for use in other pediatric cancer trials both in the upfront and relapse setting. Citation Format: Elizabeth Stewart, Kaley Blankenship, Burgess Freeman, Sara Federico, Michael Dyer. Preclinical evaluation of nano-liposomal irinotecan in pediatric solid tumor patient-derived xenografts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6716.

Enhancement of Rabbit Meat Functionality by Replacing Traditional Feed Raw Materials with Alternative and More Sustainable Freshwater Cladophora glomerata Macroalgal Biomass in Their Diets.

Today's challenges in the animal husbandry sector, with customers' demand for more beneficial products, encourage the development of strategies that not only provide more sustainable production from the field to the table but also ensure final product functionality. Thus, the current research was aimed at replacing some traditional feed raw materials in rabbit diets with C. glomerata biomass to improve the functionality of meat. For this purpose, thirty weaned (52-d-old) Californian rabbits were assigned to 3 dietary treatments: standard compound diet (SCD), SCD + 4% C. glomerata (CG4), and SCD + 8% C. glomerata (CG8). At the end of the feeding trial, 122-d-old rabbits were slaughtered, longissimus dorsi (LD) and hind leg (HL) muscles were dissected post-mortem, and moisture, protein, and lipid profiles were determined. Results revealed that CG4 treatment can increase protein (22.17 g/kg), total (192.16 g/kg) and essential (threonine, valine, methionine, lysine, and isoleucine) amino acid levels in rabbit muscles. Both inclusions gradually reduced fat accumulation in muscles (CG8 < CG4 < SCD) but improved the lipid profile's nutritional value by decreasing saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) and increasing polyunsaturated fatty acids (PUFA). As the dose of C. glomerata increased, the level of lipid oxidation decreased. Biomass supplementation enhanced PUFA/SFA and h/H levels while decreasing thrombogenicity index (TI) and atherogenic index (AI) levels in rabbit muscles, potentially contributing to the prevention of heart disease. Overall, dietary supplementation with C. glomerata biomass may be a more beneficial and sustainable nutritional approach to functionally enhancing rabbit meat.

Caloric Restriction Combined with Immobilization as Translational Model for Sarcopenia Expressing Key-Pathways of Human Pathology.

The prevalence of sarcopenia is increasing while it is often challenging, expensive and time-consuming to test the effectiveness of interventions against sarcopenia. Translational mouse models that adequately mimic underlying physiological pathways could accelerate research but are scarce. Here, we investigated the translational value of three potential mouse models for sarcopenia, namely partial immobilized (to mimic sedentary lifestyle), caloric restricted (CR; to mimic malnutrition) and a combination (immobilized & CR) model. C57BL/6J mice were calorically restricted (-40%) and/or one hindleg was immobilized for two weeks to induce loss of muscle mass and function. Muscle parameters were compared to those of young control (4 months) and old reference mice (21 months). Transcriptome analysis of quadriceps muscle was performed to identify underlying pathways and were compared with those being expressed in aged human vastus lateralis muscle-biopsies using a meta-analysis of five different human studies. Caloric restriction induced overall loss of lean body mass (-15%, p<0.001), whereas immobilization decreased muscle strength (-28%, p<0.001) and muscle mass of hindleg muscles specifically (on average -25%, p<0.001). The proportion of slow myofibers increased with aging in mice (+5%, p<0.05), and this was not recapitulated by the CR and/or immobilization models. The diameter of fast myofibers decreased with aging (-7%, p<0.05), and this was mimicked by all models. Transcriptome analysis revealed that the combination of CR and immobilization recapitulated more pathways characteristic for human muscle-aging (73%) than naturally aged (21 months old) mice (45%). In conclusion, the combination model exhibits loss of both muscle mass (due to CR) and function (due to immobilization) and has a remarkable similarity with pathways underlying human sarcopenia. These findings underline that external factors such as sedentary behavior and malnutrition are key elements of a translational mouse model and favor the combination model as a rapid model for testing the treatments against sarcopenia.

Endurance exercise under short-duration intermittent hypoxia promotes endurance performance via improving muscle metabolic properties in mice.

This study was designed to (1) investigate the effects of acute exercise under intermittent hypoxia on muscle mRNA and protein levels, and (2) clarify the mechanisms by which exercise under intermittent hypoxia improves endurance capacity. Experiment-1: Male mice were subjected to either acute endurance exercise, exercise under hypoxia (14% O2 ), exercise under intermittent hypoxia (Int, three cycles of room air [10min] and 14% O2 [15 min]). At 3h after exercise under intermittent hypoxia, sirtuin-6 mRNA levels and nuclear prolyl hydroxylases-2 protein levels were significantly upregulated in white gastrocnemius muscle in the Int group. Experiment-2: Mice were assigned to sedentary control (Sed), normoxic exercise-trained (ET), hypoxic exercise-trained (HYP) or exercise-trained under intermittent hypoxia (INT) groups. Exercise capacity was significantly greater in the INT group than in the ET and HYP group. Activity levels of citrate synthase were significantly greater in the INT group than in the HYP group in soleus (SOL) and red gastrocnemius muscles. In SOL, nuclear N-terminal PGC1α levels were considerably increased by the INT training (95% confidence interval [CI]: 1.09-1.79). The INT significantly increased pyruvate dehydrogenase complex activity levels in left ventricle (LV). Monocarboxylate transporter-4 protein levels were significantly increased after the INT training in LV. Capillary-to-fiber ratio values were significantly increased in SOL and were substantially increased in LV (CI: 1.10-1.22) after the INT training. These results suggest that exercise training under intermittent hypoxia represents a beneficial strategy for increasing endurance performance via improving metabolic properties and capillary profiles in several hind-leg muscles and the heart.

Patient‐derived pancreatic tumour organoid implantation establishes novel pre‐cachexia mouse models

AbstractBackgroundThe poor survival of pancreatic cancer patients is largely attributable to cachexia, a syndrome of severe weight and muscle loss. To investigate the aetiology of cancer cachexia, preclinical models that closely recapitulate the human disease process are essential. Patient derived tumour organoids are promising novel cancer models, but their ability to induce cachexia in mice has not been investigated. We developed two pancreatic tumour organoid‐based mouse models and demonstrate their potential for cancer cachexia research.MethodsTwo patients with pancreatic cancer, from whom tumour organoid cultures were previously established, were selected based on their cachexia phenotype. Patient 09 was characterized as cachectic according to the international consensus definition of cancer cachexia, whereas patient 12 was classified as non‐cachectic. Organoid cultures PANCO‐09b and PANCO‐12a in basement membrane extract (BME) were injected subcutaneously into the flanks of 9‐weeks old NMRI‐Foxn1nu mice (n = 8/group). A control group was injected with BME only (n = 4). Body weight was monitored every 2–3 days for 38 days. Hind limb muscle wet and dry weights were measured. Adipocyte size in inguinal white adipose tissue was measured using haematoxylin and eosin‐stained sections. Expression of genes associated with cancer cachexia in muscle and liver tissue was analysed using qPCR.ResultsEngraftment of tumour organoids was successful in 87.5% of PANCO‐09b implanted mice and in 50% of PANCO‐12a mice, with similar average tumour weights at endpoint (34.4 ± 25.1 mg vs. 32.8 ± 40.2 mg, respectively, P = 0.450). All groups initially gained weight, but PANCO‐12a implanted mice progressively lost an average body weight of 1.7 ± 0.8 g from day 28 onwards. PANCO‐12a‐implanted mice gained significantly less weight from baseline than controls (0.7 ± 0.6 g, P = 0.027). Overall body weight gain of PANCO‐09b mice was also lower but not significantly different from controls (2.0 ± 1.2 g vs. 2.9 ± 1.6 g, P = 0.961). Wet weights of hind leg muscles were negatively correlated with tumour weight but did not differ between groups. Adipocytes of PANCO‐12a implanted mice were smaller compared to SHAM as well as PANCO09b mice (P &lt; 0.0001), indicative of white adipose tissue wasting.ConclusionsImplantation of human pancreatic tumour organoids into mice negatively affects their body weight, but does not recapitulate body weight loss of donor patients. The reduced adipocyte size and inverse correlation between tumour weights and muscle weights in these mice are consistent with early‐stage cachexia or pre‐cachexia. This study shows that implantation of tumour organoids into mice provides a valuable model to investigate the processes underlying the heterogeneous presentation of cancer cachexia.

Maternal rodent exposure to di-(2-ethylhexyl) phthalate decreases muscle mass in the offspring by increasing myostatin.

Di-(2-ethylhexyl) phthalate (DEHP) and its metabolites can cross the placenta and may cause birth defects and developmental disorders. However, whether maternal DEHP exposure affects skeletal muscle development in the offspring and the pathways involved are unknown. This study investigated the effects of maternal DEHP exposure and the contribution of myostatin (MSTN) to skeletal muscle development in the offspring. Pregnant wild-type and muscle-specific myostatin knockout (MSTN KO) C57BL/6 mice were randomized to receive vehicle (corn oil) or 250mg/kg DEHP by gavage every other day until their pups were weaned (postnatal day 21 [PND21]). Body weights of the offspring mice were measured longitudinally, and their hindleg muscles were harvested at PD21. Also, C2C12 cells were treated with mono-2-ethylhexyl phthalate (MEHP), the primary metabolite of DEHP, and proteolysis, protein synthesis, and myogenesis markers were measured. The contribution of myostatin to maternal DEHP exposure-induced muscle wasting in the offspring was determined. Maternal DEHP exposure reduced body weight growth, myofibre size, and muscle mass in the offspring compared to controls (Quad: 2.70±0.1 vs. 3.38±0.23, Gastroc: 2.29±0.09 vs. 2.81±0.14, Tibialis: 1.01±0.07 vs. 1.25±0.11, mg/tibial length in mm, all P<0.01, n=35). Maternal DEHP exposure significantly increased Myostatin expression (2.45±0.41 vs. 0.03±0.00 DEHP vs. controls, P<0.01, n=5), Atrogin-1(2.68±0.65 vs. 0.63±0.01, P<0.05, n=5), MuRF1 (1.56±0.51 vs. 0.31±0.01, P<0.05, n=5), and Smad2/3 phosphorylation (4.12±0.35 vs. 0.49±0.18, P<0.05), and decreased MyoD (0.27±0.01 vs. 1.52±0.01, P<0.05, n=5), Myogenin (0.25±0.03 vs. 1.95±0.56, P<0.05, n=5), and AKT phosphorylation (4.12±0.35 vs. 1.00±0.06, P<0.05, n=5), in skeletal muscle of the offspring in MSTNflox/flox , but not in MSTN KO mice. Maternal DEHP exposure resulted in up-regulation of CCAAT/enhancer-binding protein δ (C/EBPδ, 4.12±0.35 vs. 1.00±0.19, P<0.05, n=5) in skeletal muscle of the offspring in MSTNflox/flox and MSTN KO mice (4.12±0.35 vs. 4.35±0.28, P>0.05, n=5). In vitro, C/EBPδ silencing abrogated the MEHP-induced increases in Myostatin, MuRF-1, and Atrogin-1 and decreases in MyoD and Myogenin expression. Maternal DEHP exposure impairs skeletal muscle development in the offspring by enhancing the C/EBPδ-myostatin pathway in mice.

Locomotor resilience through load-dependent modulation of muscle co-contraction

Terrestrial locomotor behavior in variable environments requires resilience to sudden changes in substrate properties. For example, walking animals can adjust to substantial changes in slope and corresponding changes in load distribution among legs. In insects, slope-dependent adjustments have mainly been examined under steady-state conditions, whereas the transition dynamics have been largely neglected. In a previous study, we showed that steady-state adjustments of stick insects to ±45deg slopes involve substantial changes in joint torques and muscle activity with only minor changes in leg kinematics. Here, we took a close look at the time course of these adjustments as stick insects compensate for various kinds of disturbances to load distribution. In particular, we tested whether the transition from one steady state to another involves distinct transition steps or follows a graded process. To resolve this, we combined simultaneous recordings of whole-body kinematics and hindleg muscle activity to elucidate how freely walking Carausius morosus negotiated a step-change in substrate slope. Step-by-step adjustments revealed that muscle activity changed in a graded manner as a function of body pitch relative to gravity. We further show analogous transient adjustment of muscle activity in response to destabilizing lift-off events of neighboring legs and the disappearance of antagonist co-activation during crawling episodes. Given these three examples of load-dependent regulation of antagonist muscle co-contraction, we conclude that stick insects respond to both transient and sustained changes in load distribution by regulating joint stiffness rather than through distinct transition steps.

Launching of a Cyborg Locust via Co-Contraction Control of Hindleg Muscles

Jumping is beneficial for microrobots because they have to face obstacles larger than their height frequently. However, compacting a jumping mechanism into the small body of a microrobot is exceptionally challenging. Instead of assembling a bio-inspired microrobot, the insect itself can be transformed into a jumping robot. Herein, we demonstrated the first-ever biohybrid jumping robot that retained the natural jumping ability of a locust. The fast kicking of the locust's hindleg was mainly induced by two muscles, flexor muscle, and extensor muscle. The elaborate structure and accurate collaboration of the muscles are critical for leg kicking, contributing to the co-contraction process. In this article, we investigated the sequences of muscular activities and demonstrated the co-contraction control exogenously. The kicking control of the hindleg relies on the accurately overlapped stimulation and the independently modulated waveform. With the help of a tiny wireless stimulator, the cyborg locust was remotely controlled to jump an average of 10.4 cm high and 42.6 cm far. Moreover, the cyborg locust retained its internal body righting mechanism, which means the robot can quickly recover its posture for consecutive jumping. This work is a foundational step towards a fully controllable biohybrid jumping robot.

Antifatigue effects of the composition of Moringa oleifera leaves and Polygonatum polysaccharide and its mechanisms

Objective: To investigate the anti-fatigue effects of composition of Moringa oleifera leaves and Polygonatum polysaccharide, and to explore the mechanisms. Methods: Thirty male Kunming mice were randomly divided into control (C) and composition of Moringa oleifera leaves and Polygonatum polysaccharide group (MP). There were 15 mice in each group. Group C was given distilled water and the group MP was given composition intragastriclly every day. The volume was 0.5 ml. After 14 days of treatment, weight-bearing swimming experiment was conducted, and exhaustive swimming time was recorded. The bearing weight was 3% of the body weight. In another experiment, 48 male Kunming mice were randomly divided into quiet control group (QC), swimming control group (SC) and composition group (MP). There were 16 mice in each group. The QC and SC groups were given distilled water intragastrically, and the group MP was treated with composition every day for 14 days. The volume was 0.5 ml. On the day 15, 30 minutes after intragastriclly administration of distilled water, blood, liver and hind leg muscle of the QC group were collected immediately. The SC and MP groups were subjected non-weight-bearing swimming experiment, and blood, liver and hind leg muscle were collected after swimming. The fatigue related indexes, oxidant/antioxidant parameters and energy metabolism indicators in serum and tissues were determined by commercial kits. Results: The exhaustive swimming time of mice in MP group was significantly longer than that in the C group (P<0.05). Compared with the control group, non-weight-bearing swimming decreased the contents of serum glucose and GSH, the contents of hepatic glycogen and ATP, the hepatic activities of SOD, LDH and ATPase, and muscle activity of GSH-Px (P< 0.05). However, serum levels of BUN and MDA were increased (P<0.05). Compared with the SC group, the composition remarkably increased the contents of serum glucose and hepatic glycogen, increased serum content of GSH, enhanced hepatic activities of SOD, LDH and ATPase and muscle activity of GSH-Px, and increased the hepatic content of ATP (P<0.05). However, the serum level of BUN was decreased (P<0.05). Conclusion: The Moringa oleifera leaves and Polygonatum polysaccharide composition possesses anti-fatigue effects. Anti-oxidant and improving energy metabolism could be the important mechanisms.

Rat Lungworm (Angiostrongylus cantonensis) in the Invasive Cuban Treefrog (Osteopilus septentrionalis) in Central Florida, USA.

Cuban treefrogs, Osteopilus septentrionalis, were grossly examined for parasites and parasite species confirmed by PCR. Angiostrongylus cantonensis larvae were recovered from the hind leg muscle of O. septentrionalis. This is the first report of the zoonotic rat lungworm in the Cuban treefrog and new geographic location (Volusia County) in Florida, US.

Effect of Dietary Rosemary and Ginger Essential Oils on the Growth Performance, Feed Utilization, Meat Nutritive Value, Blood Biochemicals, and Redox Status of Growing NZW Rabbits.

Simple SummaryThe rabbit farming industry has gained more interest due to its high productivity, high growth rate, and high-quality meat. One of the public health concerns is that global rabbit production is expected to increase to meet the increasing demand for lean meat. In the present study, we focused on the use of phytogenic feed additives (essential oils of rosemary (REO) and ginger (GEO)) as environmentally friendly supplementation to improve rabbit growth performance, physiological status, and meat quality. The results indicated that the use of REO and GEO at a dose of 0.5% dramatically improved the growth performance and feed utilization of treated rabbits. The cholesterol level decreased significantly in rabbit plasma and meat after REO and GEO treatments. The fat content tended to decline in the muscles and the triglycerides were remarkedly reduced in the plasma of treated animals. In addition, the oxidant/antioxidant balance in the plasma could be improved with supplementation with a high dose of REO and GEO. Accordingly, the use of REO and GEO as supplementations for growing rabbits could contribute to improving the sustainable production of the rabbit industry.This study was conducted to assess the impacts of using two essential oils, rosemary and ginger, on growing rabbits’ performance, carcass traits, meat composition, blood biochemicals, and the redox status of growing New Zealand White (NZW) rabbits. A total of 120 unsexed NZW rabbits, 42-days-old, were assigned randomly to five experimental groups (n = 24, 6 replicates with 4 rabbits each). The first group received a basal diet (control), the second to fifth groups were dietary supplemented daily with rosemary essential oil (REO) and ginger essential oil (GEO) at doses of 0.25 and 0.5% for each supplementation (REO-0.25, REO-0.5, GEO-0.25, and GEO-0.5), respectively. The growth traits were studied for 7 weeks, from the 7th to the 13th week of the rabbits’ age. The results revealed that final body weight, weight gain, and average daily gain increased significantly (p < 0.01) in the REO-0.5 and GEO-0.5 treatments compared to the control group. Daily feed intake decreased (p = 0.005) in essential oil treatments. Meanwhile, the feed conversion ratio improved significantly (p = 0.001) in REO and GEO at the high doses compared to the control group. The weight percentages of liver and giblets increased (p < 0.001) with both treatments of REO and GEO compared to the control group. The dietary supplementation with REO and GEO did not affect (p > 0.05) the meat composition of Longissimus dorsi and hind leg muscles. Meanwhile, REO and GEO supplementation significantly decreased cholesterol levels in the rabbit meat. Thiobarbituric acid reactive substance concentrations decreased by 10 and 15% in the meat of REO-0.5 and GEO-0.5 treatments, respectively, compared to the other groups. In the same trend, REO and GEO treatments induced a significant (p = 0.001) reduction in the plasma cholesterol concentrations and triglycerides compared to the control. The total antioxidant capacity increased by 7.60% and the malondialdehyde decreased by 11.64% in the plasma of GEO-0.5 treatment than the control. Thus, the dietary supplementation of REO and GEO have a beneficial effect in improving the productivity and meat quality of growing rabbits.

Dietary supplementation of Allium cepa skin alters intramuscular fat, muscle cholesterol, and fatty acids in rabbits.

The high polyunsaturated fatty acids content of rabbit meat predisposes it to oxidative deterioration, which often results in reduced product quality and shelf life. This fact highlights the need to improve the antioxidant status of rabbit meat. This study investigated the effects of dietary supplementation of Allium cepa skin (ACS) on growth, carcass, intramuscular fat, muscle fatty acids, cholesterol content, meat quality, antioxidant status, and sensory attributes of hind leg muscle of rabbits. Sixty-three, 28-day-old, male New Zealand rabbits (654 ± 25 g) were randomly allocated into 21 pens of three rabbits. The pens were randomly assigned to one of three dietary treatments - ACS-0: basal diet (BD) only; ACS-25: BD + 25 g kg-1 ACS; and ACS-50: BD + 50 g kg-1 ACS - for 56 days and then euthanized. Dietary ACS did not affect growth performance and retail cuts of rabbits. Muscle cholesterol was lower (P < 0.05) in ACS-supplemented rabbits than in controls. Dietary ACS lowered (P < 0.05) dissectible fat, intramuscular fat content, C14:0, C16:0, C18:0, C18:2n-6, and C20:4n-6 levels and enhanced (P < 0.05) C18:3n-3, C20:5n-3, C22:6n-3, and C22:5n-3 concentration. Dietary ACS increased muscle catalase activity in rabbits. Sensory qualities, malondialdehyde and carbonyl contents, and physicochemical attributes of hind leg muscle of rabbits after chill storage were not influenced by dietary ACS supplementation. Supplementation with 50 g kg-1 ACS reduced intramuscular fat and cholesterol content and improved muscle n-3 fatty acids without impairing the physicochemical and sensory properties of rabbit meat. © 2021 Society of Chemical Industry.

Low-activity 125I implantation into VX2 tumor rabbits and quantitative evaluation of the precise therapeutic effect.

There is still controversy about quantitatively evaluating the therapeutic effect of radioactive low-activity iodine-125 seeds (125I seeds). In the present study, a paired VX2 tumor model in a rabbit hind leg muscle was established, which is virus-induced anaplastic squamous cell carcinoma characterized by hypervascularity, rapid growth and easy propagation in the skeletal muscle. 125I seeds with 0.4 and 0.7 mCi activity were implanted into the left and right legs, respectively, using a radiation treatment planning system under positron emission tomography (PET)/computed tomography (CT) guidance. PET/CT scans and hematoxylin and eosin staining were observed at 72 h and 2 and 4 weeks after implantation to assess the therapeutic effect. The results showed that the average tumor length and standard uptake value (SUV) decreased over time, and both 125I seed groups achieved therapeutic effects at 4 weeks post-implantation. Quantitative evaluation of tumor inhibition rate, SUV variation and tumor marker ratio (Bcl-2/Bax) suggested that 0.7 mCi 125I seeds were more suitable than 0.4 mCi seeds in a clinical setting.