Resistance training and hormone replacement increase MMP-2 activity, quality and quantity of bone in ovariectomized rats

AIMS: The aim of the present study was to investigate the influence of resistance training (RT) and hormone replacement (HR) on MMP-2 activity, biomechanical and physical properties bone of ovariectomized (OVX) rats. METHODS: Sprague-Dawley female rats were grouped into six experimental groups (n = 11 per group): sham-operated sedentary (SHAM Sed), ovariectomized sedentary (OVX Sed), sham-operated resistance training (SHAM RT), ovariectomized resistance training (OVX RT), ovariectomized sedentary hormone replacement (OVX Sed-HR), and ovariectomized resistance training hormone replacement (OVX RT-HR). HR groups received implanted silastic capsules with a 5% solution of 17ß-estradiol (50 mg 17ß-estradiol/ml of sunflower oil). In a 12-week RT period (27 sessions; 4-9 climbs) the animals climbed a 1.1 m vertical ladder with weights attached to their tails. Biomechanical and physical bone analyses were performed using a universal testing machine, and MMP-2 activity analysis was done by zymography. RESULTS: Bone density and bone mineral content was higher in the RT and HR groups. The MMP-2 activity was higher in the RT and HR groups. The biomechanical analysis (stiffness, fracture load and maximum load) demonstrated better bone tissue quality in the RT associated with HR. CONCLUSION: The RT alone as well as when it is associated with HR was efficient in increasing MMP-2 activity, biomechanical and biophysical properties bone of ovariectomized rats.(AU)

GLUT2 proteins and PPARγ transcripts levels are increased in liver of ovariectomized rats: reversal effects of resistance training.

PURPOSE: This study investigated the effects of ovariectomy (Ovx) and 12 weeks of resistance training (RT) on gene expression of GLUT2, the main glucose transporter in the liver, and on PPARγ, a transcription factor known to target GLUT2 expression. METHODS: Forty Holtzman rats were divided into 5 groups: Sham-sedentary (Sed), Sham- RT, Ovx-Sed, Ovx-RT, and Ovx-Sed with hormone replacement (E2). The RT protocol consisted of sessions held every 72 h for 12 weeks, during which the animals performed 4 to 9 vertical climbs (1.1 m) at 2 min intervals with progressively heavier weights (30 g after the fourth climb) tied to the tail. The E2 silastic capsule was inserted into the rats' backs 48 hours before the first RT session. RESULTS: In addition to liver fat, GLUT2 protein levels and PPARγ transcripts were increased (P < 0.05) in Ovx compared to Sham-Sed animals, suggesting increased hepatic glucose uptake under estrogen deficient conditions. RT and E2 in Ovx rats decreased liver fat accumulation as well as GLUT2 and PPARγ gene expression to the level of Sham- Sed animals. CONCLUSION: The results of this study suggest that liver GLUT2 as well as PPARγ expression in Ovx rats are accompanied by increased fat accumulation and glucose uptake, thus providing a substrate for increased de novo lipogenesis. RT appears to be an appropriate exercise model to circumvent these effects.

Continuous blood pressure response at different intensities in leg press exercise.

BACKGROUND: Generally, the evaluation of the blood pressure response to resistance exercise has been limited to the evaluation of discontinuous casual blood pressure monitoring, often measured at the end of the exercise. DESIGN: To continuously evaluate the blood pressure response at different intensities of leg press exercise with the same duration and number of repetitions. METHODS: Seven normotensive healthy men performed an incremental test on the leg press machine at relative intensities of one repetition maximum (1RM). The blood pressure and heart rate were measured simultaneously to the incremental exercise by a photoplethysmographic method. RESULTS: The mean ± SD peak values of the heart rate, diastolic blood pressure (DBP) and systolic blood pressure (SBP) were obtained on 70% of 1RM and were 145 ± 20 bpm, 113.1 ± 15.4 mmHg, and 192.4 ± 20.0 mmHg, respectively. The SBP was characterized by a decrease followed by an increase during the sets of exercise. The decrease in the SBP was 12-22 mmHg and took approximately 25 seconds to reach the minimum value before the increase. It was observed for all participants in most of the intensities. The rate of increase in the SBP was not statistically different between the intensities. CONCLUSIONS: Both duration and intensity of exercise have an impact on the blood pressure response. Above 30% of 1RM, the SBP decreases in approximately 20 seconds and starts to increase until the end of the set of leg press exercise.

Does aerobic exercise intensity affect health-related parameters in overweight women?

The aim of this study was to compare the effect of a cycling training programme performed at intensity corresponding to the lowest value of the respiratory quotient (RQ) versus at intensity corresponding to the ventilatory threshold (VT), on body composition and health-related parameters in overweight women. Thirty-two sedentary obese women (27-42 years old) were studied in a randomized trial of either RQ (n = 17) or VT (n = 15). RQ and VT training sessions were equalized by time (60 min) and performed in a cycloergometer. Anthropometry, body composition, lipid profile, glucose, basal metabolic rate (BMR) and fitness (maximal oxygen uptake) were evaluated before and after 12 weeks of intervention. Body weight, body mass index, fatness and fitness were improved in both groups (P<0·001). Triglycerides (TG) levels decreased only in response to RQ (P<0·001) and fat-free mass (FFM) to VT (P = 0·002). No differences were observed between groups. Both exercise intensities seem to be effective for improving health in overweight women. However, low-intensity compared with the high-intensity exercise training appears to have additional benefits on TG levels and to maintenance of FFM.

Acute effects of resistance training on cytokines and osteoprotegerin in women with metabolic syndrome.

Chronic inflammation has been identified as an important component of metabolic syndrome (MetS). Inhibition of the inflammatory mediator signals is a promising strategy against insulin resistance, atherosclerosis and other problems associated with MetS. Regular exercise decreases the components associated with MetS, including inflammatory cytokines. However, the relationship between an acute resistance training (RT) session, cytokine levels and MetS is unclear. Therefore, the aim was to evaluate the effects of a single bout of acute RT on tumour necrosis factor (TNF-α), interleukins (IL) IL-1a, IL-1ß, IL-12, IL-6, IL-10 and osteoprotegerin (OPG) in women with MetS. Twenty-four women were divided into 2 groups: metabolic syndrome (MetS) and non-metabolic syndrome (Non-MetS). After the familiarization and testing for 1 repetition maximum (1RM), participants completed 3 sets of 10 repetitions in the following exercises: machine leg press, leg extension, leg curl, chest press, lat front pull-down and machine shoulder press with 60% of 1RM followed by 15 repetitions of abdominal crunches. A rest interval of 1 min was allowed between sets and exercises. Plasma TNF-α, IL-1a, IL-1ß, IL-12, IL-6, IL-10 and OPG were measured before, immediately post and 60 min after RT. MetS group showed significantly higher concentrations of IL-1ß (P = 0·024) and IL-6 (P = 0·049) and a trend for higher TNF-α values (P = 0·092) compared with Non-MetS. There was no group × time interactions after the RT session on the measured cytokines and osteoprotegerin. In conclusion, acute RT session induced no additional increase in pro-inflammatory cytokines nor a decrease in anti-inflammatory cytokines and OPG in women with MetS.

Efeitos da suplementação de fibras solúveis sobre as células do sistema imune após exercício exaustivo em ratos treinados / Effects of soluble fibers supplementation on immune system cells after exhausting exercise in trained rats

A intensidade, volume, modalidade de exercício, assim como o nível de aptidão e fatores nutricionais podem alterar a reposta imunológica. O objetivo deste estudo foi avaliar o efeito da suplementação crônica de farelo de aveia (fonte de fibras solúveis) sobre as células do sistema imunológico em ratos treinados, frente a um teste de exaustão. Foram utilizados ratos Wistar, ± dois meses, peso ± 200g, divididos em três grupos (n = 9, cada um): 1) controle sedentário (C); 2) treinado oito semanas submetido ao teste de exaustão (EX); e 3) treinado oito semanas submetido ao teste de exaustão com suplementação de 30 por cento de farelo de aveia (EXA). O treinamento consistiu de 60 minutos de natação diários, cinco dias por semana durante oito semanas. As análises realizadas foram: contagem total de leucócitos, linfócitos dos linfonodos mesentéricos, macrófagos peritoneais e capacidade fagocitária de macrófagos peritoneais. Aplicou-se o teste estatístico ANOVA two way, seguido do post hoc de Tukey com p < 0,05. O grupo EX apresentou leucocitose quando comparado com o controle, o que não ocorreu no grupo EXA, porém, na comparação entre os grupos exercitados EXA, mostrou menor leucocitose em relação a EX. Não houve alteração significativa nos linfócitos teciduais em nenhum dos grupos exercitados. Tanto o número de macrófagos peritoneais como a capacidade fagocitária desta célula foram maiores nos grupos exercitados. Porém, no grupo suplementado a capacidade fagocitária foi maior em relação ao grupo exaustão sem farelo de aveia. A suplementação de fibras solúveis demonstrou resultados benéficos com relação às alterações imunológicas induzidas pelo exercício extenuante, além de aumentar a capacidade fagocitária de macrófagos peritoniais em ratos treinados durante oito semanas submetidos ao teste de exaustão.

Exercise modality, volume, intensity, as well as physical fitness and nutritional factors may modulate the immune response. The purpose of this investigation was to verify the effects of chronic oat bran supplementation on immune cells in trained rats submitted to an extenuating test. Wistar rats (two months old), +200g weight, divided into three groups (n = 9, per group) were used: 1) a sedentary control (C) 2) trained for eight weeks submitted to an exhaustion test (EX), and 3) trained for eight weeks submitted to an exhaustion test with 30 percent oat bran supplementation (EXA). Training consisted of 60 daily minutes of swimming, five days a week, during eight weeks. The analyses conducted were: total leukocytes, lymphocytes from lymph nodes, peritoneal macrophages and peritoneal macrophages phagocytic capacity. Statistical analyses were done by the two-way ANOVA test, followed by Tukey's post hoc test (p < 0.05). EX group presented leukocytosis when compared to control; however, EXA group did not. In exercised group, comparison with EXA has shown lower leukocytosis in relation to EX. No significant alteration was observed for tissue lymphocytes in any of the exercised groups. The number of peritoneal macrophages as well as phagocytic capacity of this cell was higher in exercised groups. In oat bran supplemented group the phagocytic capacity was higher as compared to exhaustion group without oat bran. Soluble fibers supplementation has shown benefic results with regard to immune alterations induced by exhaustive exercise, and increased peritoneal macrophages phagocytic capacity in rats trained for eight weeks submitted to an exhaustion test.

Matrix metallopeptidase 2 activity in tendon regions: effects of mechanical loading exercise associated to anabolic-androgenic steroids.

Matrix metallopeptidases (MMPs) are responsible for degradation of the extracellular matrix components and tissue remodeling. To achieve a better understanding of AAS effects in rat tendon, MMP-2 activity in the proximal and distal regions of the calcanear tendon (CT) and proximal, intermediate and distal region of superficial (SFT) and deep flexor tendons (DFT) after mechanical load exercise associated with AAS was investigated. Animals were grouped into four groups: sedentary animals (S); sedentary animals with ASS supplementation (S + A); trained animals (T) and trained animals with AAS supplementation (T + A). Analysis of MMP activity in tendon extracts was done by gelatin zymography. Both proximal and distal regions of the calcanear tendon showed the lowest MMP-2 concentration and the highest proportion in MMP-2 active form. The intermediate region of the SFT differed (P < 0.01) from the proximal and distal regions with higher % of active MMP-2 in the sedentary group. The proportion of active MMP-2 decreased in the proximal region of the CT. AAS treatment strongly decreased both MMP-2 concentration and active form in the three regions of the SFT and on the proximal region of the CT, but not on the DFT. The differences in the response to exercise and AAS treatment are a result of distinct metabolism and recruitment of these tendon regions in the exercise program employed in this study.

Determination of judo endurance performance using the uchi - komi technique and an adapted lactate minimum test.

This study aimed to evaluate the viability to use Uchi-komi (UK) in the evaluation of the judo endurance performance and using lactate threshold the analysis of the blood lactate ([Lac]) and heart rate (HR) determined through a lactate minimum test. The subjects were a group of 6 male, volunteer judokas, from 25.17 ± 5.76 years old, weight 84.50 ± 23.78 kg and height 1.78 ± 0.10 m, competitors of different levels of performance (from regional to international competitions) and match experience of (11 ± 6) years old. Three tests were performed: a) 3000 m dash in track, b) the adapted test of lactate minimum for running and c) for UK, with execution of the blow ippon-seoi-nague. No significant difference was evident for the track tests and UK in relation to blood lactate and heart rate (p > 0.05) (3.87 ± 0.38 vs 4.17 ± 0.54 mmol·L(-1) and 167 ± 2 vs 152 ± 7 b·min(-1), respectively). In conclusion it is stressed that: 1) The specific test for lactate minimum in judo sport is a promising possibility of aerobic capacity evaluation and a instrument of intensity training control; 2) The metabolic profile in Vlm and UKlm is similar, because there are not differences in the [Lac] and in the HR at this intensity; 3) It is possible to estimate the training intensity through the determination of the lactate minimum intensity in running (Vlm) and the Heart Rate associated (HR) from the execution of ippon-seoi- nague (uchi-komi) in judo training; 4) The Vlm for judo athletes is approximately 88% of the V3000. Key pointsThe specific test for lactate minimum in judo sport is a promising possibility of aerobic capacity evaluation;This is a instrument for intensity training control for judo players;The metabolic profile is similar between running and uki-komi (ippon-seoi-nague techniques) at lactate minimum intensity.

[Nandrolone administration does not promote hypertrophy of soleus muscle in rats]. / A administração de nandrolona não promove hipertrofia do músculo sóleo em ratos.

Anabolic androgenic steroids (AAS) are compounds formed from testosterone or one of its derivatives, which are largely used by amateur e professional athletes to improve the athletic performance. However, the scientific information about the relation between the use of AAS and muscle hypertrophy is controversial. The aim of this study was to evaluate the effects of testosterone and physical training on muscle hypertrophy. Male Wistar rats received i.m. injections of Deca-Durabolin or vehicle during 6 weeks. Trained rats were submitted to a resistance physical training, by jumping up and down in water carrying an overload. Sedentary and trained animals were anesthetized and sacrificed. Soleus muscle was removed for the quantification of total protein and DNA concentration. In the end of the treatment, body weight of trained animals treated with vehicle or AAS was lower than the body weight of respective sedentary. Total protein concentration and the ratio muscle weight/body weight of all experimental groups were not altered. Trained group treated with AAS presented lower DNA concentration than trained group treated with vehicle. The administration of nandrolone decanoate did not promote hypertrophy on soleus muscle, not even when the use of AAS was associated to resistance physical training.

A administração de nandrolona não promove hipertrofia do músculo sóleo em ratos / Nandrolone administration does not promote hypertrophy of soleus muscle in rats

Os esteróides anabólicos androgênicos (EAA) são compostos formados a partir da testosterona ou um de seus derivados, sendo amplamente utilizados por desportistas amadores e profissionais com o objetivo de melhorar a performance atlética. Entretanto, a literatura a respeito da relação entre EAA e hipertrofia muscular é controversa. O objetivo deste estudo foi avaliar os efeitos da nandrolona e do treinamento físico sobre a hipertrofia muscular. Ratos Wistar machos receberam injeção i.m. de Deca-Durabolin® ou veículo durante 6 semanas. Os animais dos grupos treinados foram submetidos a treinamento físico resistido, através de sessões de saltos em meio líquido. Os animais sedentários e treinados foram sacrificados após anestesia e o músculo sóleo retirado para quantificação de proteínas totais e DNA. Ao final do tratamento, os animais treinados tratados com veículo ou EAA apresentaram menor peso corporal do que os respectivos grupos sedentários. Não foram observadas diferenças estatísticas na concentração de proteínas totais e na razão peso muscular/peso corporal entre os grupos experimentais. O grupo treinado tratado com EAA apresentou concentração de DNA significativamente menor do que o grupo treinado veículo. A administração de decanoato de nandrolona não promoveu hipertrofia do músculo sóleo, nem mesmo quando associada ao treinamento físico resistido.

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.