Young Rats Research Articles

Morphological aspects of the heart of young rats subjected to high and medium intensity progressive resistance physical exercise protocols

Morphological aspects of the heart of young rats subjected to high and medium intensity progressive resistance physical exercise protocols

Skeletal effects of a prolonged oral metformin treatment in adult Wistar rats.

We previously showed that a 3-week oral Metformin (MET) treatment enhances the osteogenic potential of bone marrow stromal cells (BMSCs) and improves several bone histomorphometric parameters in Wistar rats with metabolic syndrome (MetS). However, the skeletal effects of extended periods of MET are still not completely elucidated. Hence, we investigated the impact of a prolonged (3-month) MET treatment on bone architecture, histomorphometric and biomechanics variables and osteogenic potential of BMSCs in Wistar rats with or without MetS. 36 young male Wistar rats were randomized into four groups (n=9) that received either 20% fructose (F); MET (MET); F plus MET treatments (FMET); or drinking water alone (Veh). Rats were euthanized, blood was collected, and bones were dissected and processed for pQCT analysis, static and dynamic histomorphometry and bone biomechanics. In addition, BMSCs were isolated to determine their osteogenic potential. MET affected trabecular and cortical bone, altering bone architecture and biomechanics. Furthermore, MET increased the pro-resorptive profile of BMSCs. In addition, fructose-induced MetS practically did not affect the skeleton's structural or mechanical variables. A 3-month treatment with MET (with or without MetS) affects bone architecture and biomechanical variables in Wistar rats.

Sex hormone supplementation improves breathing and restores respiratory neuroplasticity following C2 hemisection in rats

In addition to loss of sensory and motor function below the level of the lesion, traumatic spinal cord injury (SCI) may reduce circulating steroid hormones that are necessary for maintaining normal physiological function for extended time periods. For men, who comprise nearly 80% of new SCI cases each year, testosterone is the most abundant circulating sex steroid. SCI often results in significantly reduced testosterone production and may result in chronic low testosterone levels. Testosterone plays a role in respiratory function and the expression of respiratory neuroplasticity. When testosterone levels are low, young adult male rats are unable to express phrenic long-term facilitation (pLTF), an inducible form of respiratory neuroplasticity invoked by acute, intermittent hypoxia (AIH). However, testosterone replacement can restore this respiratory neuroplasticity. Complicating the interpretation of this finding is that testosterone may exert its influence in three possible ways: 1) directly through androgen receptor (AR) activation, 2) through conversion to dihydrotestosterone (DHT) by way of the enzyme 5α-reductase, or 3) through conversion to 17β-estradiol (E2) by way of the enzyme aromatase. DHT signals via AR activation similar to testosterone, but with higher affinity, while E2 activates local estrogen receptors. Evidence to date supports the idea that exogenous testosterone supplementation exerts its influence through estrogen receptor signaling under conditions of low circulating testosterone. Here we explored both recovery of breathing function (measured with whole body barometric plethysmography) and the expression of AIH-induced pLTF in male rats following C2-hemisection SCI. One week post injury, rats were supplemented with either E2 or DHT for 7 days. We hypothesized that E2 would enhance ventilation and reveal pLTF following AIH in SCI rats. To our surprise, though E2 did beneficially impact overall breathing recovery following C2-hemisection, both E2 supplementation and DHT restored the expression of AIH-induced pLTF 2 weeks post-SCI.

Intake of oligoelements with cytarabine or etoposide alters dopamine levels and oxidative damage in rat brain

Research on the relationships between oligoelements (OE) and the development of cancer or its prevention is a field that is gaining increasing relevance. The aim was to evaluate OE and their interactions with oncology treatments (cytarabine or etoposide) to determine the effects of this combination on biogenic amines and oxidative stress biomarkers in the brain regions of young Wistar rats. Dopamine (DA), 5-Hydroxyindoleacetic acid (5-Hiaa), Glutathione (Gsh), Tiobarbituric acid reactive substances (TBARS) and Ca+2, Mg+2 ATPase enzyme activity were measured in brain regions tissues using spectrophometric and fluorometric methods previously validated. The combination of oligoelements and cytarabine increased dopamine in the striatum but decreased it in cerebellum/medulla-oblongata, whereas the combination of oligoelements and etoposide reduced lipid peroxidation. These results suggest that supplementation with oligoelements modifies the effects of cytarabine and etoposide by redox pathways, and may become promising therapeutic targets in patients with cancer.

The effect of magnesium sulfate on memory and anxiety-like behavior in a rat model: an investigation of its neuronal molecular mechanisms

ABSTRACT Background Anxiety is an adaptive response to potentially threatening conditions. Excessive and uncontrolled anxiety responses become nonadaptive and cause anxiety disorders. To better understand the anxiety-modulating effects of Mg sulfate, behavioral test batteries in the assessment of anxiety and learning and memory functions were performed simultaneously over a time period. This study also examines the effects of Mg sulfate compared to diazepam, an anxiolytic drug with amnestic effects on anxiety-like behavior, as well as possible oxidative-nitrosative stress and hippocampal changes in male rats exposed to predator odor. Methods Young adult Sprague-Dawley male rats were used. The rats were assessed using a comprehensive neurobehavioral test battery consisting of novel object recognition, open field, and successive alleys tasks. Anxiety was induced by cat odor, and diazepam and Mg were used as study drugs. Of the frontal cortex and hippocampus, the state of total oxidant and antioxidant and NO levels and histological examination of hippocampal CA1, CA2, CA3, and DG regions were performed. Results Diazepam- and Mg-treated rats showed an improvement in anxiety-related behavior to predator odors. Furthermore, Mg treatment alleviated some of the increasing oxidative stress in the frontal cortex and hippocampus of rats, while diazepam treatment in particular enhanced hippocampal oxidant and antioxidant activity. In addition, brain NO increase induced by animal odor exposure or diazepam treatment was ameliorated by Mg administration. Conclusions Overall, our work suggests that Mg had a partial anxiolytic effect on anxiety-like behaviors, although not as much as diazepam, and this effect varied depending on the dose. Mg treatment might counteract increased oxidative stress and elevated NO levels in the brain.

Xiaoer-Feire-Qing granules alleviate pyretic pulmonary syndrome induced by Streptococcus pneumoniae in young rats by affecting the lungs and intestines: An in vivo study based on network pharmacology

Ethnopharmacological relevanceThe traditional Chinese medicine (TCM) Xiaoer-Feire-Qing granules (XEFRQ) has been used to treat pyretic pulmonary syndrome (PPS) in children for many years. The function of the lungs is considered to be closely related to the large intestine in TCM. Purpose: We aimed to investigate the effects of XEFRQ on PPS and the underlying mechanisms via network pharmacology and animal experiments. MethodsThe TCMSP platform was used to identify the ingredients and potential targets of XEFRQ. The GeneCards, OMIM, and TTD databases were used to predict PPS-associated targets. Cytoscape 3.9.1 was employed to construct the protein–protein interaction network, and target prediction was performed by GO and KEGG analyses. For the animal experiment, a PPS model was constructed by three cycles of nasal drip of Streptococcus pneumoniae (STP; 0.5 mL/kg). The animals were randomly divided into the following four groups according to their weight (n = 10 rats per group): the blank group, the model group, the XEFRQ-L (16.3 g/kg) group, and the XEFRQ-H (56.6 g/kg) group. Rats in the blank group and the model group were given 0.5% CMC-Na by gavage. The general conditions of the rats were observed, and their food-intake, body weight, and body temperature were recorded for 14 days. After the intervention of 14 days, serum was collected to detect inflammatory cytokines (TNF-α, IL-1β, and PGE2) and neurotransmitters (5-HT, SP, and VIP). H&E staining was used to observe the pathological morphology of lung and colon tissue. AQP3 expression was detected by Western blot. In addition, the gut microbiota in cecal content samples were analyzed by 16S rDNA high-throughput sequencing. ResultsOur network analysis revealed that XEFRQ may alleviate PPS injury by affecting the levels of inflammatory cytokines and neurotransmitters and mitigating STP-induced PPS.In vivo validation experiments revealed that XEFRQ improved STP-induced PPS and reduced the expression of inflammatory cytokines and neurotransmitters. Notably, XEFRQ significantly decreased the protein expression levels of AQP3, which was associated with dry stool. Our gut microbiota analysis revealed that the relative abundance of [Eubacterium]_ruminantium_group, Colidextribacter, Romboutsia, and Oscillibacter was decreased, which means XEFRQ exerts therapeutic effects against PPS associated with these bacteria. ConclusionOur results demonstrate that XEFRQ alleviates PPS by affecting the lungs and intestines, further guiding its clinical application.

Hydroalcoholic Extract of Centella asiatica and Madecassic Acid Reverse Depressive-Like Behaviors, Inflammation and Oxidative Stress in Adult Rats Submitted to Stress in Early Life.

Major depressive disorder (MDD) is a severe disorder that causes enormous loss of quality of life, and among the factors underlying MDD is stress in maternal deprivation (MD). In addition, classic pharmacotherapy has presented severe adverse effects. Centella asiatica (C. asiatica) demonstrates a potential neuroprotective effect but has not yet been evaluated in MD models. This study aimed to evaluate the effect of C. asiatica extract and the active compound madecassic acid on possible depressive-like behavior, inflammation, and oxidative stress in the hippocampus and serum of young rats submitted to MD in the first days of life. Rats (after the first day of birth) were separated from the mother for 3h a day for 10days. When adults, these animals were divided into groups and submitted to treatment for 14days. After subjecting the animals to protocols of locomotor activity in the open field and behavioral despair in the forced swimming test, researchers then euthanized the animals. The hippocampus and serum were collected and analyzed for the inflammatory cytokines and oxidative markers. The C. asiatica extract and active compound reversed or reduced depressive-like behaviors, inflammation in the hippocampus, and oxidative stress in serum and hippocampus. These results suggest that C. asiatica and madecassic acid have potential antidepressant action, at least partially, through anti-inflammatory and antioxidant profiles.

Abstract PO1-14-09: Age-related remodeling of the systemic and breast microenvironment promotes a tumor-permissive locale for ER+ breast cancer in older women

Abstract Introduction: The peak incidence of ER+ breast cancer occurs in women around the age of 70. Compared to younger cohorts, we and others have shown that older patients with ER+ breast cancer have an enrichment of luminal disease and experience fewer recurrences, suggesting overtreatment. Differences in the biological phenotypes of tumors in older women remain poorly understood and treatment remains challenging as older patients are underrepresented in clinical trials. In this study, we hypothesized that aging alters both local and systemic hormones and inflammatory cytokines, creating a permissive environment for tumor formation and growth. To address this hypothesis, we employed a systems biology approach across multiple model systems and tissue samples. Methods: Our study included specimens from two cohorts of patients: (1) n = 90 women without breast cancer obtained from the Komen Tissue Bank, from whom we obtained matched plasma and non-cancerous breast tissue (n = 30 across age groups comprising of young donors (35-45yo), middle-aged donors (55-69yo), and older donors (≥ 70yo); and (2) n = 115 women with ER+ breast cancer (n = 25 young patients, n = 57 middle-aged patients, and n = 33 older patients) obtained from our institutional biobank, including matched plasma, tumor tissue, and tumor-adjacent tissue. From each of these sets of specimens, we measured estrogen disposition using mass spectrometry, a 22-plex panel of inflammatory markers, and transcriptomic changes using RNA-seq. Using scRNA-seq and multiplexed IHC, we further characterized the immune changes that occur with age. Lastly, we used an aged, carcinogen-induced ER+ tumor model in F344 rats (obtained from the NIA) to model tumor development and growth. Results: In the plasma, estradiol (E2) drastically decreased in post-menopausal women, leaving estrone (E1) as the predominant circulating estrogen in older women. However, the breast tumor microenvironment (TME) showed comparable levels of E1 and E2 across age groups. Multi-class concordance analysis of breast cancer tissue from RNA revealed significant increases in gene expression of the HSD17B7 enzyme and decreases in HSD17B2 enzyme across age, likely elevating local E1-to-E2 conversion and yielding high local E2 levels despite low circulating levels specifically in older women. In older patients with ER+ breast cancer, there was a significant increase in a chemokine network characterized by CCL2 and CXCL9 within the TME. scRNA-seq revealed enrichment of inflammatory M2-like macrophages in the aged TME. Immune dysfunction and decreased immunosurveillance in older patients manifested with widespread decreases in the presence of cytotoxic lymphocytes and decreased pathway enrichment of key immune pathways, such as JAK/STAT and IFNy signaling. mIHC analysis revealed decreases in CD4 and CD8 T cells and increases in M2-like macrophages in older patients in both tumor and stromal regions. Lastly, in the carcinogen-induced F344 rat model, aged rats (~ 24mo, human equivalent 60-70yo) had a shorter tumor-free interval than the younger rats (~ 4-6mo, human equivalent 20-30yo), likely due to increases in tumor-promoting inflammation and decreased immune surveillance. Ongoing mechanistic work is focused on macrophage-patient derived organoid co-cultures evaluating the functional relevance of E2, CCL2, and CXCL9 in shaping the aged TME. Conclusions: Our study of systemic and local breast hormones and cytokines in both healthy individuals and breast cancer patients showed that older women with ER+ breast cancer harbor different systemic and local environments compared to younger women. The aged TME is characterized by high E2, cytotoxic lymphocyte depletion, and immune dysfunction, creating a permissive environment for tumor formation. Future translational work should be aimed at chemo-preventative strategies to reduce the age-related chronic inflammation and immune dysfunction. Citation Format: Neil Carleton, Jian Zou, Sanghoon Lee, Dixcy Jaba Sheeba John Mary, Ruxuan Li, Jennifer Atkinson, Ziyu Huang, Hatice Osmanbeyoglu, Peter Lucas, Emilia Diego, Michael Lotze, George Tseng, Jagmohan Hooda, Ioannis Zervantonakis, Priscilla McAuliffe, Steffi Oesterreich, ADRIAN LEE. Age-related remodeling of the systemic and breast microenvironment promotes a tumor-permissive locale for ER+ breast cancer in older women [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-14-09.

Combined Effects of Early Life Stress and Prolonged Exposure to Western Diet on Emotional Responses and Gut Microbiota.

Exposure to early life stress (ELS) and maternal consumption of a high-fat and high-sugar diet can have detrimental effects on adult emotional responses. The microbiota and gut-brain axis have been proposed as playing a mediating role in the regulation of stress and emotion. Young male rats were exposed to maternal separation (MS) together with maternal and postnatal consumption of a HFS diet (45%kcal saturated fat, 17%kcal sucrose). Anxiety-like behaviour was evaluated using an elevated zero-maze, and depression-like behaviour using the forced-swim and sucrose preference tests. Microbiota composition and derived metabolites were also analysed in faecal samples using a gas chromatograph and mass spectrometry. Combined exposure to MS and lifelong consumption of a HFS diet partially reversed the abnormal anxiety-like and depression-like behaviours in early adulthood caused by each adverse factor alone. Diet composition had a greater negative impact than ELS exposure on the gut microbiota, and both environmental factors interacted with microbiota composition partially counteracting their negative effects. The effects of exposure to early life stress and a HFS diet independently are partially reversed after the combination of both factors. These results suggest that ELS and diet interact to modulate adult stress response and gut microbiota.

A new bicornuate model of rat uterus transplantation.

Uterus transplantation has revolutionized reproductive medicine for women with absolute uterine factor infertility, resulting in more than 40 reported successful live births worldwide to date. Small animal models are pivotal to refine this surgical and immunological challenging procedure aiming to enhance safety for both the mother and the child. We established a syngeneic bicornuate uterus transplantation model in young female Lewis rats. All surgical procedures were conducted by an experienced and skilled microsurgeon who organized the learning process into multiple structured steps. Animals underwent meticulous preoperative preparation and postoperative care. Transplant success was monitored by sequential biopsies, monitoring graft viability and documenting histological changes long-term. Bicornuate uterus transplantation were successfully established achieving an over 70% graft survival rate with the passage of time. The bicornuate model demonstrated safety and feasibility, yielding outcomes comparable to the unicornuate model in terms of ischemia times and complications. Longitudinal biopsies were well-tolerated, enabling comprehensive monitoring throughout the study. Our novel bicornuate rat uterus transplantation model provides a distinctive opportunity for sequential biopsies at various intervals after transplantation and, therefore, comprehensive monitoring of graft health, viability, and identification of potential signs of rejection. Furthermore, this model allows for different interventions in each horn for comparative studies without interobserver differences contrary to the established unicornuate model. By closely replicating the clinical setting, this model stands as a valuable tool for ongoing research in the field of uterus transplantation, promoting further innovation and deeper insights into the intricacies of the uterus transplant procedure.

Effects of Short-, Medium-, and Long-Term Treatment Using Photobiomodulation Therapy Combined with Static Magnetic Field in Aging Rats

(1) Background: We investigated the detrimental and protective effects of short-, medium, and long-term treatment with different doses of photobiomodulation therapy combined with static magnetic field (PBMT-sMF) during the aging process. (2) Methods: Rats were treated for 15, 30, and 60 weeks with 1, 3, 10, and 30 J of PBMT-sMF or a placebo control. In addition, eight young rats were not subjected to any procedure or treatment and were euthanized at six weeks old. Skin, muscle, bone, kidney, liver, and blood samples were analyzed. (3) Results: No differences between the groups in the morphology of the skin, muscle, and bone was observed. Glutamic pyruvic transaminase levels were increased in the placebo group after 30 and 60 weeks. Glutamic oxaloacetic transaminase levels were also increased in the placebo group after 30 weeks. An increase in creatinine in the PBMT-sMF 3, 10, and 30 J groups compared with that in the young control group was observed. No significant difference in urea levels between the groups was noted. Vascular endothelial growth factor increased in the PBMT-sMF 10 and 30 J groups after 15 weeks of treatment and in the PBMT-sMF 3 J after 60 weeks. Finally, vascular endothelial growth factor decreased in the PBMT-sMF 30 J group after 30 weeks of treatment. (4) Conclusions: PBMT-sMF did not have detrimental effects on the skin, muscle, bone, kidney, or liver after short-, medium-, and long-term treatments in aging rats. In addition, PBMT-sMF may have protective effects on the muscle tissue in aging rats after short- and long-term treatment.

The Effect of Clostridium butyricum on Gut Microbial Changes and Functional Profiles of Metabolism in High-fat Diet-fed Rats Depending on Age and Sex.

A high-fat diet (HFD) causes dysbiosis and promotes inflammatory responses in the colon. This study aims to evaluate the effects of Clostridium butyricum on HFD-induced gut microbial changes in rats. Six-week-old Fischer-344 rats with both sexes were given a control or HFD during 8 weeks, and 1-to-100-fold diluted Clostridium butyricum were administered by gavage. Fecal microbiota analyses were conducted using 16S ribosomal RNA metagenomic sequencing and predictive functional profiling of microbial communities in metabolism. A significant increase in Ruminococcaceae and Lachnospiraceae, which are butyric acid-producing bacterial families, was observed in the probiotics groups depending on sex. In contrast, Akkermansia muciniphila, which increased through a HFD regardless of sex, and decreased in the probiotics groups. A. muciniphila positively correlated with Claudin-1 expression in males (P < 0.001) and negatively correlated with the expression of Claudin-2 (P = 0.042), IL-1β (P = 0.037), and IL-6 (P = 0.044) in females. In terms of functional analyses, a HFD decreased the relative abundances of M00131 (carbohydrate metabolism module), M00579, and M00608 (energy metabolism), and increased those of M00307 (carbohydrate metabolism), regardless of sex. However, these changes recovered especially in male C. butyricum groups. Furthermore, M00131, M00579, and M00608 showed a positive correlation and M00307 showed a negative correlation with the relative abundance of A. muciniphila (P < 0.001). The beneficial effects of C. butyricum on HFD-induced gut dysbiosis in young male rats originate from the functional profiles of carbohydrate and energy metabolism.

Ethanolic extract of Persea americana Mill. (Lauraceae) seeds induced antiestrogenic effects in young female Wistar rats.

The ethanol extract of Persea americana seeds was found to inhibit the development of estrogen-dependent conditions in female Wistar rats, suggesting the ability of its secondary metabolites to interact with estrogen receptors (ERs), either as partial agonists or as antagonists. To test this hypothesis, the abovementioned extract was assessed for its ability to mimic and/or antagonize estradiol effects. Two experiments were conducted in ovariectomized (OVX) rats: (1) animals were treated with estradiol valerate (E2V; 1 mg/kg) or P.americana at doses of 25 and 50 mg/kg; (2) animals were treated with E2V alone (0.75 mg/kg) or in combination with P.americana at the abovementioned doses. Treatments were given orally for 3days and animals were sacrificed for biochemical and histological analyses of the uterus and vagina. When administered alone, P.americana did not change the histomorphology of both organs (uterus and vagina). In combination with E2V, P.americana decreased uterine weight [30 % decrease (p<0.001) at 25 mg/kg and 24 % (p<0.01) at 50 mg/kg] and epithelium height (37 % decrease). This was associated with decreased estradiol levels (at least 86 % decrease, p<0.001) in the uterus. Similarly, vagina epithelium height decreased by at least 34 % (p<0.05) when E2V was co-administered with P.americana. The seed extract of P.americana contains ER antagonist secondary metabolites accounting for its ability to inhibit the development of estrogen-dependent conditions in female rats.

Diet-induced and age-related changes in rats: the impact of N-stearoylethanolamine intake on plasma lipoproteins, adiponectin, and adipocyte cholesterol-phospholipid composition

Adiponectin is secreted by adipose tissue, associated with lipoprotein (LP) metabolism, down-regulated­ in insulin resistance states, and reduced in individuals suffering from obesity and cardiovascular diseases. Phospholipids and cholesterol are the main components of cell membranes and play a critical role in storage and secretory adipocyte functions. N-stearoylethanolamine (NSE) is a minor lipid affecting cell membrane lipids’ composition. Our study aimed to investigate plasma levels of adiponectin and cholesterol of low- and high-density LP (LDL and HDL) and adipocyte cholesterol-phospholipid (Chol-PL) composition of different age rats with high-fat diet (HFD)-induced obesity and insulin resistance and their changes under NSE administration. Our study demonstrated that chronic dietary fat overloading leads to obesity accompanied by impairment of glucose tolerance, a manifestation of dyslipidemia, and changes in plasma adiponectin levels in rats from two age groups (10-month-old and and 24-month-old). Prolonged HFD led to a reduction in plasma adiponectin levels and the growth of adipocyte cholesterol content in rats of different ages. A significant increase in plasma LDL-Chol level and main adipocyte PLs (phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, and lysophosphatidylcholine) was observed in younger rats, whereas not detected in elder animals after dietary fats overloading. The decrease in the content of anionic phospholipids (phosphatidylinositol + phosphatidylserine) was also detected in 10-month-old HFD rats compared to the control animals. NSE administration positively affected the normalization of adiponectin levels in both age HFD groups. It significantly impacted the reduction of LDL-Chol levels and the growth of HDL-Chol concentration in the blood plasma of 10-month-old rats as well as PL-composition of young HFD rats and anionic PL restoring in 24-month-old rats. The positive effect on investigated parameters makes NSE a prospective agent for treating diet-induced and age-related metabolic disorders threatening cardiovascular diseases. Keywords: adiponectin, adipose tissue, aging, cholesterol, dyslipidemia, lipoproteins, N-stearoylethanolamine, phospholipids

Proteolytic system parameters in the brain of rats with hyperhomocysteinemia

Hyperhomocysteinemia (HHcy) is now being actively studied as a potential risk factor and/or biomarker for numerous pathological conditions, including brain diseases. This study aimed to analyze the proteolytic processes in the brains of rats with HHcy. Total proteolytic activity, metal-dependent, and serine proteases activities, the content of matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinases-1, cytokines, serine proteases, total protein and medium and low molecular-weight substances (MLMWS), were evaluated. HHcy was induced by DL-homocysteine thiolactone (HTL) daily intragastric administration (200 mg·kg–1 of body weight) to young and adult albino non-linear male rats for 8 weeks following rat sacrifice and brain harvesting. It was established that HHcy causes an increase in total proteolytic activity and a rise in MLMWS levels in rat brains. Serine protease activity increased to a greater extent compared to metal-dependent one, and bigger changes were observed in young rats. Rise in MMP-9 and -10 levels (in young animals), a decline in MMP-3 and -8 levels, and a decrease in the content of interleukin-1β, interferon-γ, interleukin-4 and tumor necrosis factor-α (the last two in young animals) was also detected. No significant changes were found in serine protease content. Therefore, proteolysis intensification in the brain of rats with HHcy is more likely caused by protease up-regulation through mechanisms stimulated by homocysteine, HTL, and oxidative stress, without involving pro-inflammatory signaling pathways.

Investigating the Effect of Resistance-Aerobic Training on the Absorption and Resorption Biomarkers of Bone Tissue in Young, Adult and Elderly Male Rats

Introduction: Exercise training is likely to be a non-pharmacological intervention to improve bone health in children and the elderly. The aim of this study was to investigate the effect of resistance-aerobic training on RUX2, CTX, RANKL and ALP biomarkers in rats of different ages. Methods: In the present experimental study, 30 male Wistar rats were obtained from Instituto Pasteur of Iran and were divided into three groups according to their age: immature (2 weeks old), mature (6 weeks old) and elderly (96 weeks old). In each age group, the mice were randomly divided into two training (n=5) and control (n=5) groups. Six weeks of combined training included three sessions of aerobic training and three sessions of resistance training per week. Extracting genes by PCR method was used. One-way analysis of variance and Tukey's post hoc test and SPSS16 software were used. The significance level P≥0.05 was considered. Results: One-way analysis of variance showed that resistance-aerobic training has had a significant effect on RUNX2, RANKL and ALP variables of rats in different age groups (P &lt; 0.05). This significance was not observed in CTX variable (P &gt; 0.05). On the other hand, the results of Tukey's RUNX2 test were significantly different between the adult training and elderly training groups (p=‌0.019) as well as between the elderly control groups (p = 0.01) and adult training (p = 0.002). Regarding the RANKL variable, it showed that there was a significant difference only between the adult exercise group and the elderly control group (p = 0.01). Conclusion: Resistance-endurance training probably increases absorption and reabsorption biomarkers such as RUX2, RANKL and ALP in immature, mature and elderly male rats.

The Impact of Gut Microbiota Changes on Methotrexate-Induced Neurotoxicity in Developing Young Rats.

Methotrexate (MTX) is an essential part of therapy in the treatment of acute lymphoblastic leukemia (ALL) in children, and inferior intellectual outcomes have been reported in children who are leukemia survivors. Although several studies have demonstrated that the interaction between gut microbiota changes and the brain plays a vital role in the pathogenesis of chemotherapy-induced brain injury, preexisting studies on the effect of MTX on gut microbiota changes focused on gastrointestinal toxicity only. Based on our previous studies, which revealed that MTX treatment resulted in inferior neurocognitive function in developing young rats, we built a young rat model mimicking MTX treatment in a child ALL protocol, trying to investigate the interactions between the gut and brain in response to MTX treatment. We found an association between gut microbiota changes and neurogenesis/repair processes in response to MTX treatment, which suggest that MTX treatment results in gut dysbiosis, which is considered to be related to MTX neurotoxicity through an alteration in gut-brain axis communication.

Compartmental neuronal degeneration in the ventral striatum induced by status epilepticus in young rats' brain in comparison with adults.

According to experimental and clinical studies, status epilepticus (SE) causes neurodegenerative morphological changes not only in the hippocampus and other limbic structures, it also affects the thalamus and the neocortex. In addition, several studies reported atrophy, metabolic changes, and neuronal degeneration in the dorsal striatum. The literature lacks studies investigating potential neuronal damage in the ventral component of the striatopallidal complex (ventral striatum [VS] and ventral pallidum) in SE experimentations. To better understand the development of neuronal damage in the striatopallidal complex associated with SE, the detected neuronal degeneration in the compartments of the VS, namely, the nucleus accumbens (NAc) and the olfactory tubercle (OT), was analyzed. The experiments were performed on Wistar rats at age of 25-day-old pups and 3-month-old adult animals. Lithium-pilocarpine model of SE was used. Lithium chloride (3mmol/kg, ip) was injected 24 h before administering pilocarpine (40 mg/kg, ip). This presented study demonstrates the variability of post SE neuronal damage in 25-day-old pups in comparison with 3-month-old adult rats. The NAc exhibited small to moderate number of Fluoro-Jade B (FJB)-positive neurons detected 4 and 8h post SE intervals. The number of degenerated neurons in the shell subdivision of the NAc significantly increased at survival interval of 12 h after the SE. FJB-positive neurons were evidently more prominent occupying the whole anteroposterior and mediolateral extent of the nucleus at longer survival intervals of 24 and 48 h after the SE. This was also the case in the bordering vicinity between the shell and the core compartments but with clusters of degenerating cells. The severity of damage of the shell subdivision of the NAc reached its peak at an interval of 24 h post SE. Isolated FJB-positive neurons were detected in the ventral peripheral part of the core compartment. Degenerated neurons persisted in the shell subdivision of the NAc 1 week after SE. However, the quantity of cell damage had significantly reduced in comparison with the aforementioned shorter intervals. The third layer of the OT exhibited more degenerated neurons than the second layer. The FJB-positive cells in the young animals were higher than in the adult animals. The morphology of those cells was identical in the two age groups except in the OT.

Altered lactate/pyruvate ratio may be responsible for aging-associated intestinal barrier dysfunction in male rats.

Some evidence points to a link between aging-related increased intestinal permeability and mitochondrial dysfunction in in-vivo models. Several studies have also demonstrated age-related accumulation of the of specific deletion 4834-bp of "common" mitochondrial DNA (mtDNA) in various rat tissues and suggest that this deletion may disrupt mitochondrial metabolism. The present study aimed to investigate possible associations among the mitochondrial DNA (mtDNA) common deletion, mitochondrial function, intestinal permeability, and aging in rats. The study was performed on the intestinal tissue from (24months) and young (4months) rats. mtDNA4834 deletion, mtDNA copy number, mitochondrial membrane potential, and ATP, lactate and pyruvate levels were analyzed in tissue samples. Zonulin and intestinal fatty acid-binding protein (I-FABP) levels were also evaluated in serum. Serum zonulin and I-FABP levels were significantly higher in 24-month-old rats than 4-month-old rats (p = 0.04, p = 0.026, respectively). There is not significant difference in mtDNA4834 copy levels was observed between the old and young intestinal tissues (p > 0.05). The intestinal mitochondrial DNA copy number was similar between the two age groups (p > 0.05). No significant difference was observed in ATP levels in the intestinal tissue lysates between old and young rats (p > 0.05). ATP levels in isolated mitochondria from both groups were also similar. Analysis of MMP using JC-10 in intestinal tissue mitochondria showed that mitochondrial membrane potentials (red/green ratios) were similar between the two age groups (p > 0.05). Pyruvate tended to be higher in the 24-month-old rat group and the L/P ratio was found to be approximately threefold lower in the intestinal tissue of the older rats compared to the younger rats (p < 0.002). The tissue lactate/pyruvate ratio (L/P) was three times lower in old rats than in young rats. Additionally, there were significant negative correlations between intestinal permeability parameters and L/P ratios. The intestinal tissues of aged rats are not prone to accumulate mtDNA common deletion, we suggest that this mutation does not explain the age-related increase in intestinal permeability. It seems to be more likely that altered glycolytic capacity could be a link to increased intestinal permeability with age. This observation strengthens assertions that the balance between glycolysis and mitochondrial metabolism may play a critical role in intestinal barrier functions.

In vivo model of colorectal cancer: impact to cigarette smoke exposition on neoplasm development

Our proposal aims to investigate the impact that exposure to cigarette smoke has on the development of lesions in the colorectal mucosa of in vivo model of colorectal carcinogenesis. For that, 24 young male rats were induced to colorectal carcinogenesis and separated into two groups: exposure to cigarette smoke for 20 weeks (DMH+/Tobacco+) and control (DMH+/Tobacco-). In the group (DMH+/Tobacco+), 14.7% dysplasia and 85.29% malignant neoplasms were observed, including tubular adenocarcinoma (73%), carcinoma in situ (17%) and signet-ring cell adenocarcinoma (10%). Mononuclear inflammation and pleomorphisms were mild to moderate. In the control group, there was 7.69% dysplasia, 7.69% tubular adenoma and 84.62% malignant neoplasms, including tubular adenocarcinoma (82%), signet-ring cell adenocarcinoma (9%), carcinoma in situ (5%) and mucinous adenocarcinoma (4%). Mononuclear inflammation and pleomorphisms were moderate to severe. Thus, the experimental model showed that the lesions were predominantly malignant and with histopathological characteristics compatible with human colorectal cancer, including its possible applications for future studies.