Mitochondrial adaptations evoked with exercise are associated with a reduction in age-induced testicular atrophy in Fischer-344 rats

Pleiotropic and multi-systemic actions of physical exercise on PGC-1α signaling during the aging process

Physical training is a potent therapeutic approach for improving mitochondrial health through peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) signaling pathways. However, comprehensive information regarding the physical training impact on PGC-1α in the different physiological systems with advancing age is not fully understood. This review sheds light on the frontier-of-knowledge data regarding the chronic effects of exercise on the PGC-1α signaling pathways in rodents and humans. We address the molecular mechanisms involved in the different tissues, clarifying the precise biological action of PGC-1α, restricted to the aged cell type. Distinct exercise protocols (short and long-term) and modalities (aerobic and resistance exercise) increase the transcriptional and translational PGC-1α levels in adipose tissue, brain, heart, liver, and skeletal muscle in animal models, suggesting that this versatile molecule induces pleiotropic responses. However, PGC-1α function in some human tissues (adipose tissue, heart, and brain) remains challenging for further investigations. PGC-1α is not a simple transcriptional coactivator but supports a biochemical environment of mitochondrial dynamics, controlling physiological processes (primary metabolism, tissue remodeling, autophagy, inflammation, and redox balance). Acting as an adaptive mechanism, the long-term effects of PGC-1α following exercise may reflect the energy demand to coordinate multiple organs and contribute to cellular longevity.

Effects of Age and Lifelong Moderate-Intensity Exercise Training on Rats' Testicular Function

Aging is associated with testicular morphological and functional alterations, but the underlying molecular mechanisms and the impact of physical exercise are poorly understood. In this study, we examined the effects of age and lifelong moderate-intensity exercise on rat testis. Mature adults (35 weeks) and middle-aged (61 weeks) Wistar Unilever male rats were maintained as sedentary or subjected to a lifelong moderate-intensity treadmill training protocol. Testis weight and histology, mitochondrial biogenesis and function, and proteins involved in protein synthesis and stress response were evaluated. Our results illustrate an age-induced testicular atrophy that was associated with alterations in stress response, and mitochondrial biogenesis and function. Aging was associated with increased testicular levels of heat shock protein beta-1 (HSP27) and antioxidant enzymes. Aging was also associated with decreased mRNA abundance of the nuclear respiratory factor 1 (Nrf1), a key transcription factor for mitochondrial biogenesis, which was accompanied by decreased protein levels of the oxidative phosphorylation system (OXPHOS) complexes subunits in the testes of older animals. On the other hand, exercise did not protect against age-induced testicular atrophy and led to deleterious effects on sperm morphology. Exercise led to an even more pronounced decrease in the Nrf1 mRNA levels in testes of both age groups and was associated with decreased mRNA abundance of other mitochondrial biogenesis markers and decreased protein levels of OXPHOS complexes subunits. Lifelong moderate-intensity exercise training was also associated with an increase in testicular oxidative stress markers and possibly with reduced translation. Together, our results indicate that exercise did not protect against age-induced testicular atrophy and was not associated with beneficial changes in mitochondria and stress response, further activating mechanisms of protein synthesis inhibition.

Influence of physical activity on male fertility

Infertility is a worldwide issue impacting 15% of couples' population. Male-related infertility results in almost 50% of these cases. Considering lifestyle factors associated with infertility, here in this literature review article, we aimed to discuss training/sport effects on male-related infertility. Regarding this issue, human and animal model studies related to the subject were gathered and analysed. Exercise is well known as a general improving factor, however, excessive exercise can result in male infertility due to reduced hypothalamus-pituitary-gonadal axis (HPT) function, increased oxidative stress and chronic inflammation. Consequently, these underlying impacts result in a low testosterone production, and reduced semen quality, and can lead to infertility. In contrast, it has been revealed that exercise can improve male fertility status in lifestyle-induced infertility condition such as obesity and diabetes. Indeed, exercise, by increasing testicular antioxidant defence, reducing pro-inflammatory cytokines level and enhancing the steroidogenesis process, leads to improved spermatogenesis and semen quality in lifestyle-induced infertility. In fact, it seems that individual health status as well as exercise volume, intensity and duration are effective-involved co-factors that influence the impact that exercise will promote on male fertility. Regarding these findings, it is important to study exercise different impacts in further clinical trials in order to generate preservative guidelines for exercise and also considering exercise as a treatment option in lifestyle-induced disease management.

Acetylsalicylic acid-induced alterations in male reproductive parameters in Wistar rats and the effect of sprint interval training

The present study investigated the effect of a 5-week ASA treatment on male reproductive parameters in Wistar rats; moreover, the potential benefits of a 4-week sprint interval training (SIT) on these measures following ASA treatment were investigated. A total of 25 male rats were obtained and randomly assigned to the control group (C, n = 10) and the ASA treatment group (EP, n = 15). After 5 weeks, five rats from each group were killed and the effect of ASA treatment on the reproductive parameters was assessed. Then, the ASA treatment terminated and the remaining 10 ASA-treated rats were divided into the non-treatment group (NT, n = 5) and the exercise training group (ET, n = 5), which performed SIT 3 sessions/week for 4 weeks. Five weeks of ASA treatment resulted in a statistically significant decrease in serum testosterone level, Leydig cell number, sperm count, sperm motility, sperm viability, TDI, SI and RI, and it resulted in a significant increase in sperm nucleus maturity and sperm DNA fragmentation (p ˂ 0.05). Furthermore, 4 weeks of SIT reversed all the ASA-induced changes in male reproductive parameters (p < 0.05), but not the number of seminiferous tubules and the sperm motility (p > 0.05). A subchronic dose of ASA could lead to adverse alterations in male reproductive parameters and SIT is beneficial in reversing those alterations.

Effects of treadmill exercise on sexual behavior and reproductive parameters in chronically stressed-male rats

Exposure to chronic stress stimulates the hypothalamic-pituitary-adrenal (HPA) axis and then simultaneously inhibits hypothalamic-pituitary-gonadal axis (HPG) axis activity. The inhibition formed by the HPA axis is the main mechanism of action of stress on reproductive function. HPG axis activity is known to be changed by various factors, including exercise. Exercise has been found to have a number of positive effects on sexual behavior, reproductive hormones, and sperm parameters in studies with animal models for many years. The main aim of this study is to investigate the effects of chronic treadmill exercise on chronically stressed-male rats' sexual behavior, reproductive hormones, and sperm parameters. A total of 40 sexually adult male rats were randomly and equally divided into four groups as control, stress, exercise, and stress+exercise. Animals in the exercise group were subjected to the chronic treadmill exercise (moderate intensity) for 33 days with a periodic increase in speed and duration. Animals in the stress group were exposed to restraint stress for 1 h, 2 h, and 3 h during the first, second and third 15 days respectively. Sexual behavior parameters, hormone measurements, and sperm parameters were evaluated. The main effects of chronic exercise on sexual behavior were centered on a significant increase in the ejaculation frequency (EF) in the stress+exercise group. Also, sperm concentration and motility in the stress group significantly decreased, and then sperm motility was improved by exercise in the stress+exercise group. In sum, our results show that chronic treadmill exercise may improve the adverse effects of chronic stress on sexual behavior and sperm parameters in male rats in terms of some parameters.

BaZiBuShen alleviates altered testicular morphology and spermatogenesis and modulates Sirt6/P53 and Sirt6/NF-κB pathways in aging mice induced by D-galactose and NaNO2

ETHNOPHARMACOLOGICAL RELEVANCE

Sperm infertility and testicular atrophy are symptoms associated with aging. BaZiBuShen formula (BZBS), a patented Chinese herbal prescription composed of Semen Cuscutae, Fructus Lycii, Epimedii Folium, Fructus Schisandrae Sphenantherae, Fructus Cnidii, Fructus Rosae Laevigatae, Semen Allii Tuberosi., Radix Morindae Officinalis, Herba Cistanches, Fructus Rubi, Radix Rehmanniae Recens, Radix Cyathulae, Radix Ginseng, Cervi Cornu Pantotrichum, Hippocampus, and Fuctus Toosendan, has been used as a kidney-tonifying and anti-aging drug as well as for the treatment of impotence and male infertility in traditional Chinese medicine.

AIM OF THE STUDY

We aimed at investigating whether BZBS preserves sperm and testes morphology in aging mice, and to explore the underlying mechanisms.

MATERIALS AND METHODS

BZBS was orally administered to aging mice induced by D-galactose (D-gal) and NaNO2 for 65 days. Sperm quality and testes pathophysiological alterations were examined by a Semen Analysis System, hematoxylin-eosin staining, transmission electron microscopy, and mitochondrial complex IV activity. In addition, serum levels of total antioxidant capacity (TAC), malondialdehyde (MDA), 8-hydroxy-desoxyguanosine (8-OH-dG), reduced glutathione (GSH), oxidized glutathione disulfide (GSSG), testosterone (T), follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2) and tumor necrosis factor-α (TNF-α) were determined by ELISA. The expressions of P450 aromatase (CYP19), sirtuin 6 (Sirt6), P53, inducible nitric oxide synthase (iNOS), nuclear factor-kappa B (NF-κB)-p65, and phospho-NF-κB-p65 (NF-κB-pp65) in the testes were examined by western blot and/or immunohistochemical staining.

RESULTS

Sustained exposure to D-gal/NaNO2 caused a deterioration of sperm quality and testes morphology in this rapid aging mouse model. BZBS treatment curtailed these alterations. These beneficial effects were associated with increased serum levels of TAC, GSH/GSSG, T, E2, and FSH, and decreased levels of MDA, TNF-α, and 8-OH-dG. BZBS treatment also downregulated the expressions of P53, iNOS, and NF-κB-pp65, as well as upregulated the expressions of Sirt6 and CYP19 in aging testes.

CONCLUSIONS

BZBS preserves testicular morphology and spermatogenesis possibly via inhibition of oxidative stress and the modulation of the Sirt6/P53 and Sirt6/NF-κB signaling pathways. The results shed light on the beneficial effect of BZBS on sperm quality and fertility in aging males.

Effect of Low-Intensity Endurance Training and High-Intensity Interval Training on Sperm Quality in Male Rats with Fatty Liver

Background

We aimed to investigate the effect of low-intensity endurance training (LIET) and high-intensity inter- val training (HIIT) on sperm parameters, chromatin status, and oxidative stress in a rat model of non-alcoholic fatty liver disease (NAFLD).

Materials and Methods

For this experimental study, we divided 40 male Wistar rats into four groups (control, sham, HIIT and LIET) according to diet treatment and exercise training protocol. Liver triglycerides, sperm parameters, sperm lipid peroxidation (BODIPY C11 probe) and chromatin status [chromomycin A3 (CMA3)], and acridine orange [AO] staining) were assessed in these groups at the end of the study.

Results

The mean liver triglyceride values significantly improved in both the LIET and HIIT groups compared to the control and sham groups. The mean of testicular volume, sperm concentration, motility, intensity of sperm lipid peroxidation and DNA damage were similar within groups. While, the mean percentage of sperm lipid peroxidation and protamine deficiency were significantly higher in the LIET and HIIT groups compared to the control group.

Conclusion

Both LIET and HIIT in the rat NAFLD model had no adverse effects on testicular morphometric param- eters, sperm concentration, motility, and DNA integrity. However, the mean sperm lipid peroxidation and protamine deficiency were significantly higher in both exercise groups. Our study suggests that exercise or antioxidant supple- mentation could minimise the adverse effects of oxidant by-products of exercise.

Endogenous transient doping: physical exercise acutely increases testosterone levels-results from a meta-analysis

PURPOSE

Although endogenous testosterone levels are demonstrated to be affected by both acute exercise and resistance training, the dynamic regulation of androgen production after physical activity is still a matter of debate. This meta-analysis was designed to assess whether physical exercise acutely affects testosterone levels in men.

METHODS

The literature search was conducted to identify longitudinal trials evaluating the acute change of both total testosterone (TT) and free testosterone (fT) after physical activity in adult men. Sensitivity analyses were performed considering the sample collected (blood or saliva), the intensity of the physical exercise and the interval between the end of the exercise and the sample collection.

RESULTS

Forty-eight studies were included in the analysis, accounting for 126 trials. A total of 569 patients were enrolled (mean age 29.7 ± 13.1 years). The physical activity increased acutely TT (standardized mean difference 0.74, 95%CI: 0.56, 0.91 nmol/L), considering both serum and saliva samples (p < 0.001). Testosterone increased after moderate (p < 0.001) and high-intensity (p < 0.001) exercises, but not after mild physical activity (p = 0.19). Moreover, the testosterone increase was evident when measured immediately at the end of the exercise and within 30 min (p < 0.001), but not after 30 min (p = 0.930). Similar significant results were obtained considering fT, while SHBG did not change after physical activity (p = 0.090).

CONCLUSION

The comprehensive evaluation of the acute physical activity effect on testosterone levels identified a clear increase after exercise, irrespective of the sample collected. The main determinant of this fluctuation was the exercise intensity, with a mechanism that seems to be mostly SHBG independent. In particular, moderate/intense physical activity resulted able to increase endogenous androgenic production, albeit acutely and transitory.

TRIAL REGISTRATION NUMBER

PROSPERO registration ID: 157348.

Effect of Different Exercise Loads on Testicular Oxidative Stress and Reproductive Function in Obese Male Mice

This study is aimed at investigating the effect of different exercise loads on the reproductive function of obese male mice and the underlying mechanisms. Male mice with high-fat diet-induced obesity were divided into obesity control (OC), obesity moderate-load exercise (OME), and obesity high-load exercise (OHE) groups. The OME and OHE groups were subjected to swimming exercise 5 days per week over a duration of 8 weeks, with the exercise load progressively increased to 2 h per day in the OME group and 2 h twice per day in the OHE group. In the OC group mice without exercise regimen, we observed a decrease in mRNA expression of antioxidant enzymes, increase in free radical products, upregulation of mRNA and protein expression of nuclear factor-κB and proinflammatory cytokines, inhibition of mRNA and protein expression of testosterone synthases, decrease in the serum testosterone level and sperm quality, and increase in sperm apoptosis. Although both moderate-load exercise and high-load exercise reduced body fat, only moderate-load exercise effectively alleviated obesity-induced oxidative stress, downregulated the expression of nuclear factor-κB and proinflammatory cytokines, and reversed the decrease in mRNA and protein expression of testosterone synthases, serum testosterone level, and sperm quality. These changes were not observed in the OHE group mice. Obesity-induced testicular oxidative stress and inflammatory response decreased testosterone synthesis and sperm quality. Moderate-load exercise alleviated the negative effect of obesity on male reproductive function by decreasing testicular oxidative stress and inflammatory responses. Although high-load exercise effectively reduced body fat, its effects on alleviating oxidative stress and improving male reproductive function were limited.

Investigating the protective effect of aerobic exercise on oxidative stress and histological damages of testicular tissue associated with chlorpyrifos in male rats

The current study aimed to investigate the protective effects of moderate aerobic exercise against chlorpyrifos (CPF)-induced testes dysfunction. In excremental study, 48 adult male albino rats were randomly allocated into 16 groups of 3 rats each. Twelve experimental groups received intraperitoneal injection (5 days a week) of either 1.0 or 3.0 mg/kg body weight CPF in DMSO for 2, 4 or 6 consecutive weeks. Seven of these experimental groups were subjected to run at moderate exercise intensity for 5 days per week over 2 weeks, whereas the other groups were not. Two groups (sham groups) were administered to the equal volume of vehicle (DMSO) for 4 or 6 consecutive weeks. The remaining two groups comprised the control groups including a sedentary and an exercise-trained control group. Exercise training leads to a markedly increase in testicular superoxide dismutase (SOD) activity in CPF-exposed rats compared with corresponding sedentary animals (p < .05). Lipid peroxidation level was found to be significantly decreased in the testis of exercised animals that had been exposed to CPF (p < .05). Our results suggest that aerobic exercise can alleviate the oxidative stress induced by sub-acute CPF exposure in testis. Exercise training could barely mitigate CPF-induced testicular damages in rats.

1H NMR-based metabolomics revealed the protective effects of Guilingji on the testicular dysfunction of aging rats

ETHNOPHARMACOLOGICAL RELEVANCE

Guilingji (GLJ), a famous and classical traditional Chinese medicine (TCM) prescription, has been used to extend the lifespan and improve the life qualities of the elderly for hundreds of years in China.

AIM OF THE STUDY

We aimed to explore the protective effects of GLJ on the testicular dysfunction of aging rats, as well as the regulating effects of GLJ on the metabolic disturbance and metabolite changes in natural aging rats.

MATERIALS AND METHODS

Forty 23-month-old rats were divided randomly into four groups, including the old control group and three groups of GLJ treatment at 37.5, 75, and 150 mg/kg doses, respectively. Additionally, 10 four-month rats were included as the youth control group. Testicular dysfunction was first evaluated by measuring the changes in the wet weights of the testicles, concentration of serum testosterone (T), and morphologic changes of the testis. Subsequently, an ¹H NMR-based metabolomics approach coupled with multivariate analysis, including partial least squares discriminant analysis (PLS-DA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) was applied to monitor the metabolite changes.

RESULTS

Compared with the old control group, the wet weights of the testicles and T concentration were significantly increased, while the morphologic abnormality of testicular tissues was improved by a 4-week treatment course with GLJ. Furthermore, compared with the old control group, the urinary levels of alanine, pantothenate, phenylalanine, β-hydroxybutyrate and pyruvate were significantly decreased after a 4-week treatment course with GLJ. Additionally, we found that amino acid metabolism and pyruvate metabolism were significantly involved in the regulatory effect of GLJ.

CONCLUSIONS

The current findings provided, for the first time, sound evidence of the protective effects of GLJ on testicular dysfunction from both biochemical and metabolomics perspectives. The mechanisms of GLJ could be related to regulating amino acid metabolism and pyruvate metabolism. The current study lays an important foundation for further research and for the broad clinical application of GLJ.

Exercise effects on physiological function during aging

The decrease in cognitive/motor functions and physical abilities severely affects the aging population in carrying out daily activities. These disabilities become a burden on individuals, families and society in general. It is known that aging conditions are ameliorated with regular exercise, which attenuates the age-associated decline in maximal oxygen uptake (VO2max), production of reactive oxygen species (ROS), decreases in oxidative damage to molecules, and functional impairment in various organs. While benefits of physical exercise are well-documented, the molecular mechanisms responsible for functional improvement and increases in health span are not well understood. Recent findings imply that exercise training attenuates the age-related deterioration in the cellular housekeeping system, which includes the proteasome, Lon protease, autophagy, mitophagy, and DNA repair systems, which beneficially impacts multiple organ functions. Accumulating evidence suggests that exercise lessens the deleterious effects of aging. However, it seems unlikely that systemic effects are mediated through a specific biomarker. Rather, complex multifactorial mechanisms are involved to maintain homeostatic functions that tend to decline with age.

Exercise training causes a partial improvement through increasing testosterone and eNOS for erectile function in middle-aged rats

PURPOSE

Aging changes the balance of sex hormones and causes endothelial dysfunction in the penis, both of which are important determinants of erectile dysfunction (ED). The purpose of this study was to evaluate whether exercise training could protect against erectile dysfunction by increasing serum testosterone and penile eNOS levels in aging rats.

METHODS

A total of 14 young (2-month-old) and 14 middle-aged (18-month-old) Sprague Dawley rats were randomly assigned to either untrained control (young control, [YC], middle-aged control, [MC]) or endurance exercise-trained (young exercise, [YE], middle-aged exercise, [ME]) groups with seven rats per group. The exercise groups trained with treadmill running for 6 weeks. Body composition parameters (body weight, heart mass, liver mass, and testicular mass), serum sex hormone levels (testosterone, luteinizing hormone, follicle-stimulating hormone, and prolactin), endothelial function-related parameters in the penis (endothelial nitric oxide synthase [eNOS], CD31, alpha smooth muscle actin [α-SMA]), and maximal intracavernous pressure measure (ICP) and total ICP were analyzed in middle-aged rats.

RESULTS

The middle-aged groups showed increased body weight, as compared with the young groups, but exercise training attenuated the aging-induced increase in body weight. The middle-aged groups had lower testicular mass compared with the young groups, but exercise training attenuated aging-induced decreases in testicular mass. Exercise training increased serum testosterone levels in both the young and middle-aged groups. However, there were no changes in the levels of luteinizing hormone, follicle-stimulating hormone, and prolactin among the groups. MC group showed decreased protein levels of p-eNOS, as compared with the YC group. However, exercise training protected against aging-induced decrease in eNOS and p-eNOS protein levels in the penis. Interestingly, exercise training also increased protein levels of α-SMA and maximal ICP in the middle-aged group.

CONCLUSIONS

Exercise training has beneficial effects on erectile function in aged rats through increased testosterone production from the testis and strengthening of the cavernous endothelium with activation of eNOS. Therefore, exercise training may be a therapeutic modality for improving erectile dysfunction associated with aging.

Short photoperiod reverses obesity in Siberian hamsters via sympathetically induced lipolysis and Browning in adipose tissue

Changes in photoperiod length are transduced into neuroendocrine signals by melatonin (MEL) secreted by the pineal gland triggering seasonally adaptive responses in many animal species. Siberian hamsters, transferred from a long-day 'summer-like' photoperiod (LD) to a short-day 'winter-like' photoperiod (SD), exhibit a naturally-occurring reversal in obesity. Photoperiod-induced changes in adiposity are mediated by the duration of MEL secretion and can be mimicked by exogenously administered MEL into animals housed in LD. Evidence suggests that MEL increases the sympathetic nervous system (SNS) drive to white adipose tissue (WAT). Here, we investigated whether MEL-driven seasonally adaptive losses in body fat are associated with WAT lipolysis and browning. Hamsters were subcutaneously administered vehicle (LD+VEH) or 0.4mg/kg MEL (LD+MEL) daily for 10weeks while animals housed in SD served as a positive control. MEL and SD exposure significantly decreased the retroperitoneal (RWAT), inguinal (IWAT), epididymal (EWAT) WAT, food intake and caused testicular regression compared with the LD+VEH group. MEL/SD induced lipolysis in the IWAT and EWAT, browning of the RWAT, IWAT, and EWAT, and increased UCP1 expression in the IBAT. Additionally, MEL/SD significantly increased the number of shared MEL receptor 1a and dopamine beta-hydroxylase-immunoreactive neurons in discrete brain sites, notably the paraventricular hypothalamic nucleus, dorsomedial hypothalamic nucleus, arcuate nucleus, locus coeruleus and dorsal motor nucleus of vagus. Collectively, these findings support our hypothesis that SD-exposed Siberian hamsters undergo adaptive decreases in body adiposity due to SNS-stimulated lipid mobilization and generalized WAT browning.

The alteration of autophagy and apoptosis in the hippocampus of rats with natural aging-dependent cognitive deficits

AIMS

The present study was aim to explore aging-dependent changes in hippocampal autophagy and apoptosis in a natural aging rat model from adult to old stages and to discover a suitable age for treating neurodegenerative diseases.

METHODS

Wistar rats at 5, 18 and 24months of age were used to mimic the adulthood, initial old, and old phases, respectively. The learning and cognitive ability of the rats was detected by the Morris water maze test. Morphological changes in the hippocampus were observed. Expressions of apoptosis and autophagy-related proteins were examined by Western blot.

RESULTS

The adult group (5months) exhibited high levels of autophagy related p-ULK p-ULK-1/ULK-1 ratio, Beclin-1, LC3II and cell survival, maintaining normal learning and cognitive function and integrated hippocampal morphology. The initial old group (18 months) presented a reduced number of neurons and cognitive deficits, and exhibited high levels of apoptosis related Bax/Bcl-2 ratio, Caspase-3 activation and autophagy related p-ULK p-ULK-1/ULK-1 ratio, Beclin-1, LC3II compared to the adult group. The old group (24 months) exhibited a high level of apoptosis related Bax/Bcl-2 ratio, Caspase-3 activation and a low level of autophagy related p-ULK p-ULK-1/ULK-1 ratio, Beclin-1, LC3II compared to its younger group, as well as significant neuronal death and cognitive deficits. The degree of autophagy was generally consistent with its negative regulator, the PI3K/Akt/mTOR axis, in all groups.

CONCLUSION

Our data suggest that cognitive deficits are first observed in the initial old stage. The levels of autophagy and apoptosis tend to be opposite in the adult and old phases. High levels of autophagy and apoptosis coexist in the initial old stage. Our study indicates that up-regulation of autophagy in the initial old phase to anti-cognitive deficits must be further evaluated.

Impact of physical activity and exercise on male reproductive potential: a new assessment questionnaire

Male athletes in general are subjected to the same causes of infertility as the general population, but sports practice itself may be possibly an additional infertility factor or, at least an aggravating factor for a previously existing fertility condition; on the contrary, being physically active has been hypothesized to favor hormonal and seminological processes and could be beneficial for fertility. In this relationship, the different inherent parameters of physical activity-exercise (training volume, intensity, objective, organization and frequency) are of paramount importance. Therefore, this review discusses both the negative and positive impact of physical exercise on the male reproductive potential. Clear knowledge is lacking on this topic as incongruences exist due to the fact that studies lack standardization in assessment tools or research protocols. So that future studies can reveal more information regarding exercising male fertility, we introduce a unique questionnaire developed with the intent to help standardize future studies on male fertility and exercise.

Effects of obesity and exercise on testicular leptin signal transduction and testosterone biosynthesis in male mice

To explore the role of the testicular leptin and JAK-STAT[leptin (LEP)-JAK-STAT] pathway in testosterone biosynthesis during juvenile stages and exercise for weight loss, male C57BL/6J mice were randomly divided into normal-diet and high-fat diet groups. After 10 wk, mice in the high-fat diet-fed group were further divided randomly into obese control, obese moderate-volume exercise, and obese high-volume exercise groups. Mice in the obese moderate-volume exercise group were provided with 2 h/day, 6 days/wk swimming exercise for 8 wk, and mice in the obese high-volume exercise group underwent twice the amount of daily exercise intervention as the obese moderate-volume exercise group. The results showed that a high-fat diet causes obesity, leptin resistance, inhibition of the testicular LEP-JAK-STAT pathway, decreased mRNA and protein expression of steroidogenic factor-1, steroidogenic acute regulatory protein, and the P-450 side-chain cleavage enzyme, a decrease in the serum testosterone-to-estradiol ratio, and declines in sperm quality parameters. Both moderate and high-volume exercise were able to reduce body fat and increase the mRNA and protein expression of LEP-JAK-STAT, but only moderate exercise significantly increased the mRNA and protein expression of steroidogenic factor-1, steroidogenic acute regulatory protein, and P-450 side-chain cleavage enzyme and significantly reversed the serum testosterone-to-estradiol ratio and sperm quality parameters. These findings suggest that by impairing the testicular LEP-JAK-STAT pathway, early-stage obesity inhibits the biosynthesis of testosterone and sexual development and reduces male reproductive potential. Long-term moderate and high-volume exercise can effectively reduce body fat and improve obesity-induced abnormalities in testicular leptin signal transduction, whereas only moderate-volume exercise can reverse the negative impacts of obesity on male reproductive function.

EFFECTS OF AEROBIC TRAINING ON THE CARDIOMYOCYTES OF THE RIGHT ATRIUM OF MICE

ABSTRACT Introduction: Polypeptide hormones (natriuretic peptides, NPs) are secreted by the cardiac atria and play an important role in the regulation of blood pressure. Objective: To evaluate the effects of aerobic training on the secretory apparatus of NPs in cardiomyocytes of the right atrium. Methods: Nine-month-old mice were divided in two groups (n=10): control group (CG) and trained group (TG). The training protocol was performed on a motor treadmill for 8 weeks. Systolic blood pressure was measured at the beginning of the experiment (9 months of age) and at moment of the sacrifice (11 months of age). Electron micrographs were used to quantify the following variables: the quantitative density and area of NP granules, the relative volumes of the mitochondria, endoplasmic reticulum, and Golgi complex and the relative volume of euchromatin in the nucleus and the number of pores per 10 µm of the nuclear membrane. The results were compared by Student's t test (p< 0.05). Results: The cardiomyocytes obtained from TG mice showed increased density and sectional area of secretory granules of NP, higher relative volume of endoplasmic reticulum, mitochondria, and Golgi complex compared with the CG mice. Furthermore, the quantitative density of nuclear pores and the relative volume of euchromatin in the nucleus were significantly higher compared with the CG mice. Conclusion: Aerobic training caused hypertrophy of the secretory apparatus in the cardiomyocytes of right atrium, which could explain the intense synthesis of natriuretic peptides in trained mice with respect to the untrained mice.