Influence of high-intensity exercise training and anabolic androgenic steroid treatment on rat tissue glycogen content

Anabolic steroid consumption among gym-goers in Amman: knowledge, attitudes, and behaviors

Background

The use of Anabolic-androgenic steroids (AAS) among gym members has become a significant concern due to their impact on physical training and performance. Research worldwide indicates a notable prevalence of AAS use among athletes and gym attendees, often involving substances that are neither safe nor legal.

Objectives

This study aims to determine the prevalence of AAS use among gym attendees in Amman, Jordan, and to explore the knowledge, attitudes, and behaviors associated with AAS use.

Methods

The study involved 399 participants from 35 randomly selected gyms in the metropolitan area of Amman, Jordan. A cluster sampling technique was used to select a diverse and representative sample of gym attendees. Data was collected using a self-administered questionnaire that assessed AAS use, knowledge, attitudes, and behavioral factors. Statistical analyses were conducted using chi-square tests to explore the relationships between AAS use and categorical variables, while logistic regression was employed to identify predictors of AAS use.

Results

The analysis revealed significant associations between AAS use and various factors, including knowledge, attitudes, behavioral factors, and demographic variables such as gender, age, exercise frequency, reasons for exercise, and total exercise duration. The study identified key predictors of AAS use among gym attendees in Amman, highlighting the importance of demographic and behavioral factors.

Conclusion

The findings underscore the need for targeted interventions to address misconceptions and promote safer practices among gym-goers in Amman. The study provides critical insights that can guide the development of strategies, policy adjustments, and educational initiatives aimed at reducing AAS misuse and fostering a healthier gym culture in the region.

Effect of high-intensity interval training on aerobic capacity and fatigue among patients with prostate cancer: a meta-analysis

OBJECTIVE

This study focused on evaluating whether high-intensity interval training (HIIT) had an effect on aerobic capacity and fatigue among patients with prostate cancer (PCa) and exploring its effect on the immune system of PCa patients.

METHODS

To investigate the potential effect of HIIT on patients with prostate cancer, a meta-analysis was carried out. From January 2012 to August 2022, studies that met predefined criteria were searched in the Scopus, PubMed, Web of Science, and EBSCO databases. Analysis of the standardized mean differences was performed using Review Manager 5.4.1 software with a 95% confidence interval.

RESULTS

This review examined a total of 6 articles. There were 215 male patients with PCa involved, and the mean age was 64.4 years. According to the results of the meta-analysis, the HIIT group (n = 63) had greater VO_2peak (P<0.01) than the control group (CON) (n = 52) (P = 0.30, I² = 19% in the heterogeneity test; MD, 1.39 [0.50, 2.27]). Moreover, fatigue was significantly different (P<0.01) between the HIIT (n = 62) and CON (n = 61) groups (P = 0.78, I² = 0% in the heterogeneity test; SMD, -0.52 [-0.88, -0.16]). Furthermore, among PCa patients, HIIT showed higher efficacy (P < 0.01) in decreasing PSA than the CON regimen (P=0.22, I² = 34% in the heterogeneity test; MD, -1.13 [-1.91, -0.34]).

CONCLUSIONS

HIIT improves aerobic capacity, fatigue, and PSA levels among PCa patients but does not significantly affect IL-6 or TNF-α content. Therefore, HIIT may be a novel and potent intervention scheme for PCa patients.

Nandrolone combined with strenuous resistance training impairs myocardial proteome profile of rats

We aimed to investigate the effects of high doses of nandrolone decanoate and resistance training (RT) on the proteomic profile of the left ventricle (LV) of rats, using a label-free quantitative approach. Male rats were randomized into four groups: untrained vehicle (UTV), trained vehicle (TV), untrained nandrolone (UTN), and trained nandrolone (TN). Rats were familiarized with the exercise training protocol (jump exercise) for one week. Jump-exercise was performed five days a week for 6 weeks, with 30 s of inter-set rest intervals. Nandrolone was administrated for 6 weeks (5 mg/kg, twice a week, via intramuscular). Systolic and diastolic arterial pressure and heart rate were measured 48 h post-training. LV was isolated and collagen content was measured. The expression of cardiac proteins was analyzed by ultra-efficiency liquid chromatography with mass spectrometry high / low collision energy (UPLC/MSE). Nandrolone and RT led to cardiac hypertrophy, even though high doses of nandrolone counteracted the RT-induced arterial pressures lowering. Nandrolone also affected the proteome profile negatively in LV of rats, including critical proteins related to biological processes (metabolism, oxidative stress, inflammation), structural function and membrane transporters. Our findings show physiological relevance since high doses of nandrolone induced detrimental effects on the proteome profile of heart tissue and hemodynamic parameters of rats. Furthermore, as nandrolone abuse has become increasingly common among recreational athletes and casual fitness enthusiasts, we consider that our findings have clinical relevance as well.

Role of cholecystokinin and oxytocin in slower gastric emptying induced by physical exercise in rats

Vigorous exercise can induce gastrointestinal disorders such decreased gastric emptying pace, while low-intensity exercise can accelerate gastric motility. However, the mechanisms of these effects are still unknown. We investigated the possible neurohumoral mechanisms involved in these phenomena. In sedentary (Sed) and acute exercise (Ex) groups of rats, we assessed the activation of c-Fos in NTS and DVMN and the plasma levels of CCK and OXT. Separate groups received pretreatment with the oxytocin antagonist atosiban (AT), the cholecystokinin antagonist devazepide (DVZ), or the TRPV1 receptor inhibitor capsazepine (CAPZ). AT, DVZ and CAPZ treatments prevented (p<0.05) slower gastric emptying induced by acute exercise. The gene expression of OXT decreased (P<0.05) while that of CCK increased (P<0.05) in the gastric fundus and pylorus of the Ex group, while the plasma levels of OXT rose (p<0.05) and of CCK declined (p<5.05). We also observed activation (p<0.05) of c-Fos-sensitive neurons in the NTS and DVMN of exercised rats. In conclusion, acute exercise slowed gastric emptying by the vagal afferent pathway, which involved activation of CCK1/OXT/TRPV1 sensitivity.

Preclinical techniques to investigate exercise training in vascular pathophysiology

Atherosclerosis is a dynamic process starting with endothelial dysfunction and inflammation and eventually leading to life-threatening arterial plaques. Exercise generally improves endothelial function in a dose-dependent manner by altering hemodynamics, specifically by increased arterial pressure, pulsatility, and shear stress. However, athletes who regularly participate in high-intensity training can develop arterial plaques, suggesting alternative mechanisms through which excessive exercise promotes vascular disease. Understanding the mechanisms that drive atherosclerosis in sedentary versus exercise states may lead to novel rehabilitative methods aimed at improving exercise compliance and physical activity. Preclinical tools, including in vitro cell assays, in vivo animal models, and in silico computational methods, broaden our capabilities to study the mechanisms through which exercise impacts atherogenesis, from molecular maladaptation to vascular remodeling. Here, we describe how preclinical research tools have and can be used to study exercise effects on atherosclerosis. We then propose how advanced bioengineering techniques can be used to address gaps in our current understanding of vascular pathophysiology, including integrating in vitro, in vivo, and in silico studies across multiple tissue systems and size scales. Improving our understanding of the antiatherogenic exercise effects will enable engaging, targeted, and individualized exercise recommendations to promote cardiovascular health rather than treating cardiovascular disease that results from a sedentary lifestyle.

Strength training protects against prostate injury in alcoholic rats

Alcoholic injury can alter the hormonal signaling pathway and lead to glucose and lipid metabolism disorders. In this study, we investigated whether the strength training could exert protective effects against the alterations caused by ethanol consumption on prostatic metabolism. A UChB, ethanol-preferring rats were used in this study. Strength training was conducted for 3 days per week for 13 weeks, rats performed jumps in water carrying a weight load strapped to their chests as part of a strength training protocol. The reduced alcohol consumption by strength training was accompanied by increased glucose, serum lipid profile, total protein levels, and reduced hormonal levels. The results of protein expression of prostatic tissues in the ethanol- and strength training-treated groups indicated that "steroidal hormone receptors," "fatty acid translocation," and "cell regulation" were significantly different between ethanol- and strength training-treated groups. Taken together, these findings show that strength training effectively ameliorated prostatic injuries in alcoholic rats at least partially by acting on lipids receptors and steroidal hormone receptors pathway, suggesting the strength training as a potential novel therapeutic strategy for treating prostate injuries caused by ethanol.

Ação do estanozolol sobre a histologia renal e hepática em ratos treinados com natação

RESUMO No presente estudo, foram analisados os efeitos do estanozolol, associado ou não à atividade física, sobre o hemograma, o peso ponderal, a ingestão líquida e sólida, a urinálise, a expressão do VEGF-A renal e o glicogênio hepático, além da histopatologia hepática e renal em ratos Wistar. Foram utilizados 32 ratos Wistar, machos, jovens, separados em quatro grupos: GC (grupo controle); GCE (grupo controle-exercício); GT (grupo tratamento-esteroide); GTE (grupo tratamento-esteroide-exercício). Os animais dos grupos GT e GTE (n=16) foram submetidos a injeções subcutâneas, cinco dias/semana, durante 30 dias, na concentração de 5mg/kg de estanozolol diluído em 1mL de óleo de gergelim, utilizado como veículo. A natação foi definida como exercício físico. Houve aumento no peso dos animais submetidos ao estanozolol e ao exercício a partir da terceira semana de uso e aumento da excreção urinária a partir da quinta semana; os demais parâmetros da urinálise foram semelhantes entre os grupos. O uso de estanozolol associado ou não à atividade física promoveu redução da expressão do VEGF-A nos rins e do glicogênio hepático, além de alterações histopatológicas nesses órgãos. Quanto à hematologia, houve uma diminuição dos leucócitos no GTE em relação aos grupos GT e GCE. Quanto aos linfócitos, houve um aumento no GT e uma diminuição no GTE, e, em relação ao número de plaquetas, houve diminuição no GTE quando comparado ao GT e ao GCE Assim, conclui-se que estanozolol na dose de 5,0mg/kg causa alterações renais e hepáticas em ratos Wistar, podendo levar à falência dos rins e do fígado.

Physical resistance training-induced changes in lipids metabolism pathways and apoptosis in prostate

BACKGROUND

Altered lipid metabolism is an important characteristic of neoplastic cells, with androgens and growth factors being major regulatory agents of the lipid metabolism process. We investigated the effect of physical resistance training on lipid metabolism and apoptosis in the adult Wistar rat prostate.

METHODS

Two experimental groups represented sedentary and physical resistance training. Three days per week for 13 weeks, rats performed jumps in water carrying a weight load strapped to their chests as part of a physical resistance exercise protocol. Two days after the last training session, rats were anesthetized and sacrificed for blood and prostate analysis.

RESULTS

Physical exercise improved feeding efficiency, decreased weight gain, regulated the serum-lipid profile, and modulated insulin-like growth factor-1 (IGF-1) and free testosterone concentration. Furthermore, upregulation of cluster of differentiation 36 (CD36), sterol regulatory element binding protein-1 (SREBP-1), sterol regulatory element-binding protein cleavage-activating protein (SCAP), and reduced lysosome membrane protein (LIMPII) expression were also observed in the blood and prostates of trained rats. Consistent with these results, caspase-3 expression was upregulating and the BCL-2/Bax index ratio was decreased in trained rats relative to sedentary animals.

CONCLUSIONS

In this work, physical resistance training can alter lipid metabolism and increase markers of apoptosis in the prostate, suggesting physical resistance training as a potential novel therapeutic strategy for treating prostate cancer.

Intense resistance training induces pronounced metabolic stress and impairs hypertrophic response in hind-limb muscles of rats

Skeletal muscle hypertrophy is an exercise-induced adaptation, particularly in resistance training (RT) programs that use large volumes and low loads. However, evidence regarding the role of rest intervals on metabolic stress and muscular adaptations is inconclusive. Thus, we aimed to investigate the effects of a strenuous RT model (jump-training) on skeletal muscle adaptations and metabolic stress, considering the scarce information about RT models for rats. We hypothesized that jump-training induces metabolic stress and influences negatively the growth of soleus (SOL) and extensor digitorum longus (EDL) muscles of rats. Male Wistar rats (aged 60 days) were randomly assigned to non-trained or trained groups (n = 8/group). Trained rats performed jump-training during 5 days a week for 1, 3, or 5 weeks with 30 s of inter-set rest intervals. Forty-eight hours after the experimental period, rats were euthanized and blood samples immediately drawn to measure creatine kinase activity, lactate and corticosterone concentrations. Muscle weight-to-body weight ratio (MW/BW), cross-sectional area (CSA) and myosin heavy chain (MHC) isoform expression were determined. Higher lactate levels occurred after 20 min of training in weeks 1 and 3. Corticosterone levels were higher after 5 weeks of training. Jump-training had negative effects on hypertrophy of types-I and II muscle fibers after 5 weeks of training, as evidenced by decreased CSA and reduced muscle weight. Our results demonstrated that pronounced metabolic stress and impairment of muscle growth might take place when variables of exercise training are not appropriately manipulated. Lay summary Resistance training (RT) has been used to increase muscle mass. In this regard, training variables (intensity, volume, and frequency) must be strictly controlled in order to evoke substantial muscular fitness. This study shows that rats submitted to 5 weeks of intensive resistance jump-training - high intensity, large volume, and short rest intervals - present high levels of blood corticosterone associated with negative effects on hypertrophy of types-I and II muscle fibers.

Nandrolone combined with strenuous resistance training reduces vascular nitric oxide bioavailability and impairs endothelium-dependent vasodilation

Anabolic Androgenic Steroids (AASs) misuse has increased among adolescents and recreational athletes due to their potential effects on muscle hypertrophy. On the other hand, AAS might induce alterations on cardiovascular system, although some controversies regarding AAS on vascular properties remain unknown. To address this question, we aimed to investigate the effects of high doses of nandrolone combined with strenuous resistance training (RT) on function and structure of thoracic aorta. Rats were randomized into four groups: non-trained vehicle (NTV), trained vehicle (TV), non-trained nandrolone (NTN), and trained nandrolone (TN), and submitted to 6 weeks of treatment with nandrolone (5 mg/kg, twice a week) and/or resistance training. In vitro response of thoracic aorta to acetylcholine (ACh) was analyzed. Vascular nitric oxide (NO) and reactive oxygen species (ROS) synthesis were evaluated using 4,5-diaminofluorescein diacetate (DAF-2) and hydroethidine fluorescent techniques, respectively. Thoracic aorta was processed for microscopy analyses and tunica media thickness was measured. ACh-mediated relaxation response was impaired in endothelium intact aortic rings isolated from trained rats (TV and TN) as compared with their matched non-trained groups. TN rats showed reduced ACh-mediated vasodilatation than NTN rats. NO production and bioavailability decreased in thoracic aorta of nandrolone-treated rats in relation to their matched non-trained group (NTN vs. NTV; TN vs. TV). ROS production and tunica media thickness were increased in TN rats when compared with TV rats. These findings indicate that high doses of nandrolone combined with strenuous RT affect NO bioavailability and might induce endothelial dysfunction and arterial morphological alterations.

Effects of resistance training on liver structure and function of aged rats

The aging process may cause negative physiological changes. However, exercises as resistance training (RT) have been considered an important intervention to attenuate these changes. Additionally, liver plays an important role in blood glucose homeostasis in exercise.

AIM

This study aimed to analyze the effects of RT on the liver components of aged animals.

METHODS

Male Wistar rats were divided into two groups: 24 months' group (CONTROL); and group submitted to a progressive RT protocol for 16 weeks (EXERCISE). Both groups were sacrificed at 24 months.

RESULTS

We observed a decrease in blood flow due to the practice of resistance exercises. Besides, our results showed that hepatic tissue plays an important role in glycemic homeostasis during RT. In addition, RT increased mitogen capacity of hepatocytes.

CONCLUSIONS

Our study showed many implications for the knowledge about the effects of strength training on old animals' liver.

Androgenic-anabolic steroids inhibited post-exercise hypotension: a case control study

BACKGROUND

There is evidence of hypertensive effects caused by anabolic androgenic steroids (AAS). A single exercise session promotes the acute reduction of blood pressure, but the effects of AAS on this phenomenon are unknown.

OBJECTIVES

To investigate the post-exercise blood pressure response in androgenic-anabolic steroid users.

METHODS

Thirteen AAS users (23.9±4.3 years old) and sixteen controls (22.1±4.5 years old) performed a session of aerobic exercise. Heart rate and blood pressure were assessed before exercise and during a 60min post-exercise resting period. Repeated ANOVA measures were used to determine differences between the groups.

RESULTS

While the control group had a significant reduction in post-exercise systolic blood pressure of up to 13.9±11.6mmHg at 40min, this phenomenon was limited among AAS users who reached a maximum of 6.2±11.5mmHg at 60min. The between groups comparison revealed significant higher post-exercise hypotension (PEH) for the control group at 30min (-12.9±14.1mmHg versus -2.9±7.6mmHg), 40min (-13.9±11.6mmHg versus -2.5±8.3mmHg), 50min (-13.9±13.9mmHg versus -5.0±7.9mmHg) and 60min (-12.5±12.8mmHg versus -6.2±11.5mmHg). There was no significant diastolic PEH in any of the groups.

CONCLUSIONS

This study demonstrated impaired systolic post-exercise hypotension as a new adverse effect of AAS usage.

Increased Adipose and Muscle Insulin Sensitivity Without Changes in Serum Adiponectin in Young Female Collegiate Athletes

BACKGROUND

Effects of endurance training on adipose insulin sensitivity in association with body composition, circulating adipokines, and markers of inflammation have been studied less in young Asian subjects.

METHODS

Adipose insulin sensitivity/resistance was compared between 170 female Japanese collegiate athletes and 311 nonathletes (18-24 years), who underwent measurements of serum adipokines, markers of insulin sensitivity, inflammation, and dual-energy X-ray absorptiometry. Two separate subsamples of two groups of women underwent either a 75-gram oral glucose tolerance test or a standardized meal test, but not both.

RESULTS

As compared with nonathletes, athletes, characterized by higher skeletal muscle mass and lower percentage of body fat (both P < 0.001), had lower adipose insulin resistance (IR) (a product of fasting insulin and nonesterified fatty acid (NEFA) and lower leptin/adiponectin ratio (both P < 0.001). Although athletes had lower postmeal/postglucose insulinemia (P = 0.009 and 0.01, respectively), the two groups did not differ in postmeal percentage NEFA suppression and postmeal/postglucose glycemia, suggesting increased insulin sensitivity in adipose tissue and skeletal muscle, respectively. Serum leptin (P < 0.001) and tumor necrosis factor-α (P = 0.01) were lower in athletes, whereas adiponectin and homeostasis model assessment IR did not differ.

CONCLUSIONS

Endurance training was associated with increased insulin sensitivity in adipose tissue as well as skeletal muscle without changes in circulating adiponectin even in young, normal-weight Japanese women.

Animal models of resistance exercise and their application to neuroscience research

BACKGROUND

Numerous studies have demonstrated that participation in regular resistance exercise (e.g., strength training) is associated with improvements in mental health, memory, and cognition. However, less is known about the neurobiological mechanisms mediating these effects. The goal of this mini-review is to describe and evaluate the available animal models of resistance exercise that may prove useful for examining CNS activity.

NEW METHOD

Various models have been developed to examine resistance exercise in laboratory animals.

COMPARISON WITH EXISTING METHODS

Resistance exercise models vary in how the resistance manipulation is applied, either through direct stimulation of the muscle (e.g., in situ models) or through behavior maintained by operant contingencies (e.g., whole organism models). Each model presents distinct advantages and disadvantages for examining central nervous system (CNS) activity, and consideration of these attributes is essential for the future investigation of underlying neurobiological substrates.

RESULTS

Potential neurobiological mechanisms mediating the effects of resistance exercise on pain, anxiety, memory, and drug use have been efficiently and effectively investigated using resistance exercise models that minimize stress and maximize the relative contribution of resistance over aerobic factors.

CONCLUSIONS

Whole organism resistance exercise models that (1) limit the use of potentially stressful stimuli and (2) minimize the contribution of aerobic factors will be critical for examining resistance exercise and CNS function.

Short and Long Term Effects of High-Intensity Interval Training on Hormones, Metabolites, Antioxidant System, Glycogen Concentration, and Aerobic Performance Adaptations in Rats

The purpose of the study was to investigate the effects of short and long term High-Intensity Interval Training (HIIT) on anaerobic and aerobic performance, creatinine, uric acid, urea, creatine kinase, lactate dehydrogenase, catalase, superoxide dismutase, testosterone, corticosterone, and glycogen concentration (liver, soleus, and gastrocnemius). The Wistar rats were separated in two groups: HIIT and sedentary/control (CT). The lactate minimum (LM) was used to evaluate the aerobic and anaerobic performance (AP) (baseline, 6, and 12 weeks). The lactate peak determination consisted of two swim bouts at 13% of body weight (bw): (1) 30 s of effort; (2) 30 s of passive recovery; (3) exercise until exhaustion (AP). Tethered loads equivalent to 3.5, 4.0, 4.5, 5.0, 5.5, and 6.5% bw were performed in incremental phase. The aerobic capacity in HIIT group increased after 12 weeks (5.2 ± 0.2% bw) in relation to baseline (4.4 ± 0.2% bw), but not after 6 weeks (4.5 ± 0.3% bw). The exhaustion time in HIIT group showed higher values than CT after 6 (HIIT = 58 ± 5 s; CT = 40 ± 7 s) and 12 weeks (HIIT = 62 ± 7 s; CT = 49 ± 3 s). Glycogen (mg/100 mg) increased in gastrocnemius for HIIT group after 6 weeks (0.757 ± 0.076) and 12 weeks (1.014 ± 0.157) in comparison to baseline (0.358 ± 0.024). In soleus, the HIIT increased glycogen after 6 weeks (0.738 ± 0.057) and 12 weeks (0.709 ± 0.085) in comparison to baseline (0.417 ± 0.035). The glycogen in liver increased after HIIT 12 weeks (4.079 ± 0.319) in relation to baseline (2.400 ± 0.416). The corticosterone (ng/mL) in HIIT increased after 6 weeks (529.0 ± 30.5) and reduced after 12 weeks (153.6 ± 14.5) in comparison to baseline (370.0 ± 18.3). In conclusion, long term HIIT enhanced the aerobic capacity, but short term was not enough to cause aerobic adaptations. The anaerobic performance increased in HIIT short and long term compared with CT, without differences between HIIT short and long term. Furthermore, the glycogen super-compensation increased after short and long term HIIT in comparison to baseline and CT group. The corticosterone increased after 6 weeks, but reduces after 12 weeks. No significant alterations were observed in urea, uric acid, testosterone, catalase, superoxide dismutase, sulfhydryl groups, and creatine kinase in HIIT group in relation to baseline and CT.

The effects of resistance exercise on cocaine self-administration, muscle hypertrophy, and BDNF expression in the nucleus accumbens

BACKGROUND

Exercise is associated with positive outcomes in drug abusing populations and reduces drug self-administration in laboratory animals. To date, most research has focused on aerobic exercise, and other types of exercise have not been examined. This study examined the effects of resistance exercise (strength training) on cocaine self-administration and BDNF expression, a marker of neuronal activation regulated by aerobic exercise.

METHODS

Female rats were assigned to either exercising or sedentary conditions. Exercising rats climbed a ladder wearing a weighted vest and trained six days/week. Training consisted of a three-set "pyramid" in which the number of repetitions and resistance varied across three sets: eight climbs carrying 70% body weight (BW), six climbs carrying 85% BW, and four climbs carrying 100% BW. Rats were implanted with intravenous catheters and cocaine self-administration was examined. Behavioral economic measures of demand intensity and demand elasticity were derived from the behavioral data. BDNF mRNA expression was measured via qRT-PCR in the nucleus accumbens following behavioral testing.

RESULTS

Exercising rats self-administered significantly less cocaine than sedentary rats. A behavioral economic analysis revealed that exercise increased demand elasticity for cocaine, reducing consumption at higher unit prices. Exercising rats had lower BDNF expression in the nucleus accumbens core than sedentary rats.

CONCLUSIONS

These data indicate that resistance exercise decreases cocaine self-administration and reduces BDNF expression in the nucleus accumbens after a history of cocaine exposure. Collectively, these findings suggest that strength training reduces the positive reinforcing effects of cocaine and may decrease cocaine use in human populations.

The glucoregulatory response to high-intensity aerobic exercise following training in rats with insulin-treated type 1 diabetes mellitus

An acute bout of exercise elicits a rapid, potentially deleterious, reduction in blood glucose in patients with type 1 diabetes mellitus (T1DM). In the current study, we examined whether a 10-week aerobic training program could alleviate the rapid exercise-associated reduction in blood glucose through changes in the glucoregulatory hormonal response or increased hepatic glycogen storage in an insulin-treated rat model of T1DM. Thirty-two male Sprague-Dawley rats were divided evenly into 4 groups: non-T1DM sedentary (C) (n = 8), non-T1DM exercised (CX) (n = 8), T1DM sedentary (D) (n = 8), and T1DM exercised (DX) (n = 8). Exercise training consisted of treadmill running for 5 days/week (1 h, 27 m/min, 6% grade) for 10 weeks. T1DM was induced by multiple streptozotocin injections (20 mg/kg) followed by implantation of subcutaneous insulin pellets. At week 1, an acute exercise bout led to a significant reduction in blood glucose in DX (p < 0.05), whereas CX exhibited an increase in blood glucose (p < 0.05). During acute exercise, serum epinephrine was increased in both DX and CX (p < 0.05), whereas serum glucagon was increased during recovery only in CX (p < 0.01). Following aerobic training in DX, the exercise-mediated reduction in blood glucose remained; however, serum glucagon increased to the same extent as in CX (p < 0.05). DX exhibited significantly less hepatic glycogen (p < 0.001) despite elevations in glycogenic proteins in the liver (p < 0.05). Elevated serum epinephrine and decreased hepatic adrenergic receptor expression were also evident in DX (p < 0.05). In summary, despite aerobic training in DX, abrupt blood glucose reductions and hepatic glycogen deficiencies were evident. These data suggest that sympathetic overactivity may contribute to deficiencies in hepatic glycogen storage.

Aerobic Exercise Recovers Disuse-induced Atrophy Through the Stimulus of the LRP130/PGC-1α Complex in Aged Rats

Physical training has been shown to be important to the control of muscle mass during aging, through the activation of several pathways including, IGF1-AKT and PGC-1α. Also, it was demonstrated that LRP130, a component of the PGC-1α complex, is important for the PGC-1α-dependent transcription of several mitochondrial genes in vivo. To explore the role of physical training during aging, we investigated the effects on muscle recovery after short-term immobilization followed by 3 or 7 days with aerobic or resistance training. Using morphological (myofibrillar adenosine triphosphatase activity, to assess the total muscle fiber cross-sectional area (CSA) and the frequency of specific fiber types), biochemical (myosin heavy chain), and molecular analyses (quantitative real-time PCR, functional pathways analyses, and Western blot), our results indicated that after an atrophic stimulus, only animals subjected to aerobic training showed entire recovery of cross-sectional area; aerobic training reduced the ubiquitin-proteasome system components involved in muscle atrophy after 3 days of recovery, and the upregulation in PGC-1α expression enhanced the process of muscle recovery by inhibiting the FoxO pathway, with the possible involvement of LRP130. These results suggest that aerobic training enhanced the muscle regeneration process after disuse-induced atrophy in aged rats possibly through of the LRP130/PGC-1α complex by inhibiting the ubiquitin-proteasome system.

Effect of exercise training and anabolic androgenic steroids on hemodynamics, glycogen content, angiogenesis and apoptosis of cardiac muscle in adult male rats

OBJECTIVES

To investigate the effects of exercise training and anabolic androgenic steroids (AAS) on hemodynamics, glycogen content, angiogenesis, apoptosis and histology of cardiac muscle.

METHODS

Forty rats were divided into 4 groups; control, steroid, exercise-trained and exercise-trained plus steroid groups. The exercise-trained and trained plus steroid groups, after one week of water adaptation, were exercised by jumping into water for 5 weeks. The steroid and trained plus steroid groups received nandrolone decanoate, for 5 weeks. Systolic blood pressure and heart rate (HR) were monitored weekly. Heart weight/body weight ratio (HW/BW ratio) were determined. Serum testosterone, vascular endothelial growth factor (VEGF), cardiac caspase-3 activity and glycogen content were measured.

RESULTS

Compared with control, the steroid group had significantly higher blood pressure, HR, sympathetic nerve activity, testosterone level, HW/BW and cardiac caspase-3 activity. Histological examination revealed apoptotic changes and hypertrophy of cardiomyocytes. In exercise-trained group, cardiac glycogen, VEGF and testosterone levels were significantly higher while HR was significantly lower than control. HW/BW was more than control confirmed by hypertrophy of cardiomyocytes with angiogenesis on histological examination. Trained plus steroid group, had no change in HR, with higher blood pressure and HW/BW than control, cardiac glycogen and serum VEGF were higher than control but lower than exercise-trained group. Histological examination showed hypertrophy of cardiomyoctes with mild angiogenesis rather than apoptosis.

CONCLUSION

When exercise is augmented with AAS, exercise-associated cardiac benefits may not be fully gained with potential cardiac risk from AAS if used alone or combined with exercise.

Effects of nandrolone and resistance training on the blood pressure, cardiac electrophysiology, and expression of atrial β-adrenergic receptors

AIMS

This study was performed to assess isolated and combined effects of nandrolone and resistance training on the blood pressure, cardiac electrophysiology, and expression of the β1- and β2-adrenergic receptors in the heart of rats.

MAIN METHODS

Wistar rats were randomly divided into four groups and submitted to a 6-week treatment with nandrolone and/or resistance training. Cardiac hypertrophy was accessed by the ratio of heart weight to the final body weight. Blood pressure was determined by a computerized tail-cuff system. Electrocardiography analyses were performed. Western blotting was used to access the protein levels of the β1- and β2-adrenergic receptors in the right atrium and left ventricle.

KEY FINDINGS

Both resistance training and nandrolone induced cardiac hypertrophy. Nandrolone increased systolic blood pressure depending on the treatment time. Resistance training decreased systolic, diastolic and mean arterial blood pressure, as well as induced resting bradycardia. Nandrolone prolonged the QTc interval for both trained and non-trained groups when they were compared to their respective vehicle-treated one. Nandrolone increased the expression of β1- and β2-adrenergic receptors in the right atrium for both trained and non-trained groups when they were compared to their respective vehicle-treated one.

SIGNIFICANCE

This study indicated that nandrolone, associated or not with resistance training increases blood pressure depending on the treatment time, induces prolongation of the QTc interval, and increases the expression of β1- and β2-adrenergic receptors in the cardiac right atrium, but not in the left ventricle.

Liver and plasma nesfatin-1 responses to 6 weeks of treadmill running with or without zizyphus jujuba liquid extract in female rat

BACKGROUND

Nesfatin-1 is a protein derived from a precursor molecule of the nucleobindin-2 gene, and acts as an anorexigenic peptide on food intake behavior, and its level isinfluenced by nutritional status, food composition [fat and carbohydrate (CHO)], and physical exercise.

OBJECTIVES

The aim of this study was to investigate the effects of 6 weeks of treadmill running (at high intensity) program with and without zizyphus jujuba (high carbohydrate content) crud extraction on liver nesfatin-1, ATP, glycogen, and its plasma concentrations in female rats.

MATERIALS AND METHODS

Twenty-eight Wistar female rats (6-8 weeks old100-120 g of weight) were randomly assigned to saline-control (SC), saline-training (ST), zizyphus jujuba-control (ZJC), and zizyphus jujuba-training (ZJT) groups. Rats ran on a motor-driven treadmill at 35 m/min, 60 min/day, 5 days/week for 6 weeks. Animals received ZJ extraction and saline at the dose of 1.25 mL/100g of body weight. Seventy-two hours after the last training session rats were killed, a portion of liver excited, and plasma was collected for nesfatin-1, ATP, and glycogen measurements. A one-way ANOVA method, and Pearson correlation were employed. P < 0.05 was considered as significant.

RESULTS

A higher and significant liver nesfatin-1 level was found in ZJ groups (p < 0.005), but plasma nesfatin-1 responded differently. Changes in liver nesfatin-1 were accompanied with an increase in liver glycogen,but not ATP contents.

CONCLUSIONS

The Findings indicate that higher liver nesfatin-1 and glycogen content by ZJ extraction might be due to the ZJ high CHO content, and it could be consideredas an anti-appetite herb.

The effects of high-intensity resistance exercise on the blood lipid profile and liver function in hypercholesterolemic hamsters

It is well established that atherogenic dyslipidemia, characterized by high levels of triglycerides (TG), total cholesterol (TC), and low-density lipoprotein (LDL) cholesterol and low levels of high-density lipoprotein (HDL) cholesterol, constitutes important risk factors for cardiovascular disease. Regular exercise has been associated with a reduced risk for metabolic diseases. However, studies supporting the concept that resistance exercise is a modifier of blood lipid parameters are often contradictory. The aim of this study was to investigate the effects of high-intensity resistance exercise on the serum levels of TG, TC, HDL and non-HDL cholesterol, glucose, and the liver function enzymes alanine aminotransferase (ALT, EC 2.6.1.2) and aspartate aminotransferase (AST, EC 2.6.1.1) in golden Syrian hamsters (Mesocricetus auratus (Waterhouse, 1839)) fed a hypercholesterolemic diet. Sedentary groups (S) and exercise groups (E) were fed a standard diet (SS and ES) or a cholesterol-enriched diet (standard plus 1% cholesterol, SC and EC). Resistance exercise was performed by jumps in the water, carrying a load strapped to the chest, representing 10 maximum repetitions (10 RM, 30 s rest, five days per week for five weeks). Mean blood sample comparisons were made by ANOVA + Tukey or ANOVA + Kruskal-Wallis tests (p < 0.05) to compare parametric and nonparametric samples, respectively. There were no differences in blood lipids between the standard diet groups (SS and ES) (p > 0.05). However, the EC group increased the glucose, non-HDL, and TC levels in comparison with the ES group. Moreover, the EC group increased the TG levels versus the SC group (p < 0.05). In addition, the ALT levels were increased only by diet treatment. These findings indicated that high-intensity resistance exercise contributed to dyslipidemia in hamsters fed a hypercholesterolemic diet, whereas liver function enzymes did not differ in regards to the exercise protocol.

Creatine does not promote hypertrophy in skeletal muscle in supplemented compared with nonsupplemented rats subjected to a similar workload

The purpose of this study was to test the hypothesis that creatine (Cr) supplementation may promote an additional hypertrophic effect on skeletal muscle independent of a higher workload on Cr-supplemented trained muscle compared with Cr-nonsupplemented trained muscle. Male Wistar rats (2-3 months old, 250-300 g) were divided randomly into 4 groups (n = 8 per group): nontrained without Cr supplementation (CO), nontrained with Cr supplementation (CR), trained without Cr supplementation (TR), and trained with Cr supplementation (TRCR). Creatine supplementation was given at 0.5 g/kg per day. Trained groups were submitted to a 5-week resistance training program (5 d/wk). The progressive workloads were similar between the Cr-supplemented (TRCR) and Cr-nonsupplemented (TR) trained groups; the only difference between groups was the Cr treatment. After the 5-week experiment, the soleus muscle was dissected to analyze the cross-sectional area (CSA) of the muscle fibers. Resistance training promoted a significant (P < .05) increase in the muscle fibers CSA in the TR group compared with the CO group. However, no additional hypertrophic effect was found when Cr supplementation was added to training (TRCR vs TR comparison, P > .05). In addition, Cr supplementation alone did not promote significant alterations in muscle fiber CSA (CR vs CO comparison, P > .05). We conclude that Cr supplementation does not promote any additional hypertrophic effect on skeletal muscle area when Cr-supplemented trained muscles are submitted to same training regimen than Cr-nonsupplemented trained muscles. Specifically, any benefits of Cr supplementation on hypertrophy gains during resistance training may not be attributed to a direct anabolic effect on the skeletal muscle.

Gene expression in distinct regions of rat tendons in response to jump training combined with anabolic androgenic steroid administration

The aim of this study was to evaluate the expression of key genes responsible for tendon remodeling of the proximal and distal regions of calcaneal tendon (CT), intermediate and distal region of superficial flexor tendon (SFT) and proximal, intermediate and distal region of deep flexor tendon (DFT) submitted to 7 weeks of jumping water load exercise in combination with AAS administration. Wistar male rats were grouped as follows: sedentary (S), trained (jumping water load exercise) (T), sedentary animals treated with AAS (5 mg/kg, twice a week) and animals treated with AAS and trained (AAST). mRNA levels of COL1A1, COL3A1, TIMP-1, TIMP-2, MMP-2, IGF-IEa, GAPDH, CTGF and TGF-β-1 were evaluated by quantitative PCR. Our main results indicated that mRNA levels alter in different regions in each tendon of sedentary animals. The training did not alter the expression of COL1A1, COL3A, IGF-IEa and MMP-2 genes, while AAS administration or its combination with training reduced their expression. This study indicated that exercise did not alter the expression of collagen and related growth factors in different regions of rat tendon. Moreover, the pattern of gene expression was distinct in the different tendon regions of sedentary animals. Although, the RNA yield levels of CT, SFT and DFT were not distinct in each region, these regions possess not only the structural and biochemical difference, but also divergence in the expression of key genes involved in tendon adaptation.

High-intensity resistance training with insufficient recovery time between bouts induce atrophy and alterations in myosin heavy chain content in rat skeletal muscle

The aim of this study was to test whether high-intensity resistance training with insufficient recovery time between bouts, could result in a decrease of muscle fiber cross-sectional area (CSA), alter fiber-type frequencies and myosin heavy chain (MHC) isoform content in rat skeletal muscle. Wistar rats were divided into two groups: trained (Tr) and control (Co). Tr group were subjected to a high-intensity resistance training program (5 days/week) for 12 weeks, involving jump bouts into water, carrying progressive overloads based on percentage body weight. At the end of experiment, animals were sacrificed, superficial white (SW) and deep red (DR) portions of the plantaris muscle were removed and submitted to mATPase histochemical reaction and SDS-PAGE analysis. Throughout the experiment, both groups increased body weight, but Tr was lower than Co. There was a significant reduction in IIA and IID muscle fiber CSA in the DR portion of Tr compared to Co. Muscle fiber-type frequencies showed a reduction in Types I and IIA in the DR portion and IID in the SW portion of Tr compared to Co; there was an increase in Types IIBD frequency in the DR portion. Change in muscle fiber-type frequency was supported by a significant decrease in MHCI and MHCIIa isoforms accompanied by a significant increase in MHCIIb isoform content. MHCIId showed no significant differences between groups. These data show that high-intensity resistance training with insufficient recovery time between bouts promoted muscle atrophy and a transition from slow-to-fast contractile activity in rat plantaris muscle.

Biomechanical responses of different rat tendons to nandrolone decanoate and load exercise

Androgenic-anabolic steroids (AAS) have been associated with an increased incidence of tendon rupture. The aim of this study was to compare the biomechanical properties of the rat calcaneal tendon (CT), superficial flexor tendon (SFT), and deep flexor tendon (DFT), and to determine the effect of jump training in association with AAS. Animals were separated into four groups: sedentary, trained, AAS-treated sedentary rats (AAS), and AAS-treated and trained animals. Mechanical testing showed that the CT differed from the DFT and SFT, which showed similar mechanical properties. Jump caused the CT to exhibit an extended toe region, an increased resistance to tensional load, and a decreased elastic modulus, characteristics of an elastic tendon capable of storing energy. AAS caused the tendons to be less compliant, and the effects were reinforced by simultaneous training. The DFT was the most affected by training, AAS, and the interaction of both, likely because of its involvement in the toe-off step of jumping, which we suggest is related to the rapid transmission of force as opposed to energy storage. In conclusion, tendons are differently adapted to exercise, but responded equally to AAS, showing reduced flexibility, which is suggested to increase the risk of tendon rupture in AAS consumers.

Treinamento aeróbio em natação melhora a resposta de parâmetros metabólicos de ratos durante teste de esforço

Foram investigados os efeitos do treinamento aeróbio em natação com baixa intensidade sobre as respostas do lactato e da glicose sanguíneos de ratos durante teste de esforço. Ratos Wistar adultos foram distribuídos aleatoriamente em dois grupos: sedentário (n = 6) e treinado (n = 6). Todos receberam água e ração ad libitum e foram mantidos em ambiente com temperatura de 22 ± 2ºC e ciclo claro/escuro de 12 horas. O grupo treinado foi submetido a um programa de natação contínua sem sobrecarga, 30 min/dia, cinco dias/semana, por seis semanas. Três dias após a última sessão de treino, as concentrações sanguíneas de lactato e glicose foram medidas em três momentos durante dois testes de esforço de 20 minutos (repouso, 10 min e 20 min), sendo um sem carga e outro com carga (5% do peso corporal), separados por dois dias. Observou-se correlação inversa entre lactato e glicose durante o exercício (ρ = - 0,74; P < 0,001). A concentração de lactato elevou-se do repouso para 10 min (P < 0,05) e estabilizou-se entre 10 e 20 min, em ambos os grupos nos dois testes. No teste com carga, o lactato estabilizou-se em níveis mais elevados frente aos níveis sem carga (P < 0,05), nos dois grupos. Os animais treinados exibiram níveis de lactato mais baixos do que os sedentários (P < 0,05) nos dois testes. A glicose sanguínea decaiu do repouso até 20 min nos sedentários, no teste com carga (P < 0,05). Nos treinados, a glicose sanguínea estabilizou-se em ambos os testes (P > 0,05). Conclui-se que o treinamento aeróbio em natação aplicado foi capaz de alterar as respostas do lactato e glicose sanguíneos de ratos durante os testes de esforço.

Effects of creatine supplementation during resistance training on myosin heavy chain (MHC) expression in rat skeletal muscle fibers

The purpose of this study was to utilize a rodent model to test the hypothesis that creatine (Cr) supplementation during resistance training would influence the pattern of slow-twitch muscle myosin heavy chain (MHC) isoforms expression. Male Wistar rats (2-3 months old, 250-300 g) were divided into 4 groups: Nontrained without creatine supplementation (CO), nontrained with creatine supplementation (CR), trained without creatine supplementation (TR), and trained with creatine supplementation (TRCR). TR and TRCR groups were submitted to a resistance training program for 5 weeks (5 days/week) for morphological and biochemical analysis of the soleus muscle. Weightlifting exercise involved jump sessions into water, carrying progressive overload equivalent to percentage of body weight. CR and TRCR groups were given creatine at 0.5 g/kg(-1)/d(-1). Both Cr supplementation and resistance training alone or associated did not result in significant alterations (p > 0.05) in body weight gain, food intake, and muscle weight in the CR, TR and TRCR groups compared to the CO group. Also compared to the CO group, the CR group showed a significant (p < 0.02) increase in MHCI content and a reduction in MHCII; inversely, the TR group increased the MHCII content and reduced MHCI (p < 0.02). When combined, both creatine and resistance training did not promote significant (p > 0.05) changes in MHC content of the TRCR group compared to the CO group. The data show that Cr supplementation provides a potential action to abolish the exercise-induced MHC isoform transitions from slow to fast in slow-twitch muscle. Thus, Cr supplementation might be a suitable strategy to maintaining a slow phenotype in slow muscle during resistance training, which may be favorable to maintenance of muscle oxidative capacity of endurance athletes.

Effects of administering testosterone undecanoate in rats subjected to physical exercise: effects on the estrous cycle, motor behavior and morphology of the liver and kidney

The aim of the work was evaluate the effects of testosterone undecanoate (TU) treatment combined with moderate physical training on: the estrous cycle, body weight (BW), motor behavior (MB), and the morphohistology of the reproductive system, the liver and kidney in rats. Female Wistar rats (180 g - 250 g) were divided as follows: sedentary + TU (S + TU), trained + TU (T + TU), sedentary + vehicle (S + V), trained + vehicle (T + V). The rats swam 50 min/Day, strapped with a 5% BW load, for 4 weeks. During this training, (BW) was monitored daily as well as the estrous cycle (EC) by vaginal smear. The TU (15 mg/kg s.c) was administered 3 times/week for 4 weeks. At the end of the study, data on MB, BW and morphohistopathological changes in viscera were compiled. The (T + TU) group had on average, a higher (BW) in the fourth week compared to the first week, and (BW) higher than (S + V) and (S + TU) groups. We noted an interruption in the EC and a decrease in weight of ovaries in animals treated with TU. In addition, there was an increase in the relative weight of the heart in groups (T + V) and (T+ TU), and kidneys in group (T + TU). Histopathological analysis showed periportal congestion and isolated foci of hepatic necrosis in rats with TU. Thus, TU combined with training abolished the EC, promoted ovarian atrophy, liver necrosis, cardiac hypertrophy and a decrease in motor activity.

Influence of anabolic steroid on anxiety levels in sedentary male rats

The aim of this study was to evaluate the influence of nandrolone decanoate on anxiety levels in rats. Male Wistar rats were treated with nandrolone decanoate (5mg/kg, two times per week, i.m.) or vehicle (propylene glycol--0.2 ml/kg, two times per week, IM) for 6 weeks. Control rats were subject only to procedures related to their routine husbandry. By the end of 6 weeks, all groups (24-29 rats/group) were submitted to the elevated plus maze test in order to evaluate their anxiety level. Some of these animals (12-14/group) were treated with diazepam (1 mg/kg i.p.) 30 min before the elevated plus maze test. Nandrolone decanoate significantly decreased the percentage of time spent in the open arms (1.46+/-0.49%) compared with control (3.80+/-0.97%) and vehicle (3.96+/-0.85%) groups, with no difference between control and vehicle treatments. The percentage of open arm entries was also reduced in the group treated with nandrolone decanoate in comparison with the vehicle and control. No changes in the number of closed arm entries were detected. Diazepam abolished the effects of nandrolone decanoate on the percentage of time in, and entries into the open arms. The present study showed that chronic treatment with a high dose of nandrolone decanoate increased the anxiety level in male rats.

Characterization of circannual patterns of metabolic recovery from activity inRana catesbeianaat 15°C

We characterized carbohydrate metabolism following activity in the American bullfrog, Rana catesbeiana, and compared whole body metabolic profiles between two seasons. Forty-eight adult male Rana catesbeianawere chronically cannulated and injected with[U-14C]l-lactic acid sodium salt in either summer (June)or winter (January) after acclimation for 2 weeks at 15°C with a 12 h:12 h L:D photoperiod. Following injection with [14C]lactate, frogs were either allowed to rest for 240 min (REST), hopped for 2 min on a treadmill and immediately sacrificed (PE), or hopped for 2 min on a treadmill and allowed to recover for 240 min (REC 4). Exercise caused a significant increase in blood lactate level from 2.7±0.1 mmol l–1 at rest to 17.0±2.1 mmol l–1 immediately following exercise. This increase persisted throughout the recovery period, with average blood lactate level only reduced to 13.7±1.1 mmol l–1 after 240 min of recovery, despite complete recovery of intramuscular lactate levels. Lactate levels were not significantly different between seasons in any treatment (REST, PE, REC4), in either gastrocnemius muscle or blood. The vast majority of [14C]lactate was recovered in the muscle, in both winter (86.3%) and summer (87.5%). Season had no effect on total amount of 14C label recovered. [14C]Lactate was measured in the forms of lactate, glucose and glycogen, in the liver and the muscle sampled. The most robust difference found in seasonal metabolism was that both the liver and the gastrocnemius contained significantly higher levels of intracellular free glucose under all treatments in winter. These data suggest that, overall, bullfrogs accumulate and slowly clear lactate in a manner quite similar to findings in fish, other amphibians and lizards. Additionally, our findings indicate that lactate metabolism is not highly influenced by season alone, but that intracellular glucose levels may be sensitive to annual patterns.

The comparison of immobility time in experimental rat swimming models

Rat swimming models have been used in studies about stress and depression. However, there is no consensus about interpreting immobility (helplessness or adaptation) in the literature. In the present study, immobility time, glucose and glycogen mobilization, corticosterone and the effect of desipramine and diazepam were investigated in two different models: swimming stress and the forced swimming test. Immobility time was lower in swimming stress than in the forced swimming test. Both swimming models increased corticosterone levels in comparison with control animal levels. Moreover, swimming stress induced higher corticosterone levels than the forced swimming test did [F(2,14)=59.52; p<0.001]. Liver glycogen content values differed from one another (swimming stress<forced swimming test<control), [F(2,17)=32.08; p<0.001]. The glycogen content values in the gastrocnemius [F(2,16)=11.35; p=0.026] and soleus [F(2,16)=8.68; p=0.006] muscles were lower during swimming stress in comparison with the forced swimming test and control. The immobility time was recorded and measured in another group treated with desipramine and diazepam in two protocols: a single session of forced swimming test or swimming stress and two sessions (pre- and retest) of forced swimming model or swimming stress. Desipramine decreased the immobility time in the forced swimming test in both the single [F(2,25)=20.63; p<0.0001] and retest [F(2,37)=7.28; p=0.002] swimming session, without changes in the swimming stress model. Diazepam increased the immobility time in the swimming stress but not in the forced swimming test during the single [F(2,26)=11.24; p=0.0003] and retest sessions [F(2,38)=4.17; p=0.02]. It was concluded that swimming stress and the forced swimming test induced different behavior, hormonal and metabolic responses and represented different situations to the animal.

Androgenic-anabolic steroids associated with mechanical loading inhibit matrix metallopeptidase activity and affect the remodeling of the achilles tendon in rats

BACKGROUND

The indiscriminate use of anabolic-androgenic steroids has been shown to induce pathologic changes in the Achilles tendon in several situations.

PURPOSE

To study tendon remodeling in rats treated with anabolic-androgenic steroids combined with an exercise program.

STUDY DESIGN

Controlled laboratory study.

METHODS

Wistar rats were grouped as follows: sedentary (group I), injected with anabolic-androgenic steroids only (group II), trained only (group III), and trained and injected with anabolic-androgenic steroids (group IV). The trained groups performed jumps in water: 4 series of 10 jumps each, with an overload of 50% to 70% of the animal's body weight and a 30-second rest interval between series, for 6 weeks. Anabolic-androgenic steroids (5 mg/kg) were injected subcutaneously. Activity of matrix metallopeptidases, a marker for tendon remodeling, was analyzed in tissue extracts by zymography on gelatin-sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

RESULTS

Morphological analyses of tendons showed that in group II, the most external layer that covers the tendon was thicker with aggregation of the collagen fibers, suggesting an increase in collagen synthesis. In group IV, an inflammatory infiltrate and fibrosis in tendons as well as a pronounced increase of the serum corticosterone level were observed. This training protocol upregulated matrix metallopeptidase activity, whereas anabolic-androgenic steroid treatment strongly inhibited this activity. The appearance of lytic bands with molecular masses of approximately 62 and 58 kDa suggests the activation of matrix metallopeptidase-2.

CONCLUSION

Anabolic-androgenic steroid treatment can impair tissue remodeling in the tendons of animals undergoing physical exercise by down-regulating matrix metallopeptidase activity, thus increasing the potential for tendon injury.

CLINICAL RELEVANCE

Since the AAS abuse is so widespread, a better comprehension of the pathological effects induced by these drugs may be helpful for the development of new forms of therapy of AAS-induced lesions.