RESUMO
AIM: To evaluate the effects of resistance exercise training (RET) and/or glutamine supplementation (GS) on signaling protein synthesis in adult rat skeletal muscles. METHODS: The following groups were studied: (1) control, no exercise (C); (2) exercise, hypertrophy resistance exercise training protocol (T); (3) no exercise, supplemented with glutamine (G); and (4) exercise and supplemented with glutamine (GT). The rats performed hypertrophic training, climbing a vertical ladder with a height of 1.1 m at an 80° incline relative to the horizontal with extra weights tied to their tails. The RET was performed three days a week for five weeks. Each training session consisted of six ladder climbs. The extra weight load was progressively increased for each animal during each training session. The G groups received daily L-glutamine by gavage (one g per kilogram of body weight per day) for five weeks. The C group received the same volume of water during the same period. The rats were euthanized, and the extensor digitorum longus (EDL) muscles from both hind limbs were removed and immediately weighed. Glutamine and glutamate concentrations were measured, and histological, signaling protein contents, and mRNA expression analyses were performed. RESULTS: Supplementation with free L-glutamine increased the glutamine concentration in the EDL muscle in the C group. The glutamate concentration was augmented in the EDL muscles from T rats. The EDL muscle mass did not change, but a significant rise was reported in the cross-sectional area (CSA) of the fibers in the three experimental groups. The levels of the phosphorylated proteins (pAkt/Akt, pp70S6K/p70S6K, p4E-BP1/4E-BP1, and pS6/S6 ratios) were significantly increased in EDL muscles of G rats, and the activation of p4E-BP1 was present in T rats. The fiber CSAs of the EDL muscles in T, G, and GT rats were increased compared to the C group. These changes were accompanied by a reduction in the 26 proteasome activity of EDL muscles from T rats. CONCLUSION: Five weeks of GS and/or RET induced muscle hypertrophy, as indicated by the increased CSAs of the EDL muscle fibers. The increase in CSA was mediated via the upregulated phosphorylation of Akt, 4E-BP1, p70S6k, and S6 in G animals and 4E-BP1 in T animals. In the EDL muscles from T animals, a decrease in proteasome activity, favoring a further increase in the CSA of the muscle fibers, was reported.
Assuntos
Glutamina , Condicionamento Físico Animal , Ratos , Animais , Glutamina/farmacologia , Glutamina/metabolismo , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Ratos Wistar , Músculo Esquelético/metabolismo , Hipertrofia , Suplementos Nutricionais , Glutamatos/farmacologia , Condicionamento Físico Animal/fisiologiaRESUMO
Aim: To evaluate the effects of resistance exercise training (RET) and/or glutamine supplementation (GS) on signaling protein synthesis in adult rat skeletal muscles. Methods: The following groups were studied: (1) control, no exercise (C); (2) exercise, hypertrophy resistance exercise training protocol (T); (3) no exercise, supplemented with glutamine (G); and (4) exercise and supplemented with glutamine (GT). The rats performed hypertrophic training, climbing a vertical ladder with a height of 1.1 m at an 80° incline relative to the horizontal with extra weights tied to their tails. The RET was performed three days a week for five weeks. Each training session consisted of six ladder climbs. The extra weight load was progressively increased for each animal during each training session. The G groups received daily L-glutamine by gavage (one g per kilogram of body weight per day) for five weeks. The C group received the same volume of water during the same period. The rats were euthanized, and the extensor digitorum longus (EDL) muscles from both hind limbs were removed and immediately weighed. Glutamine and glutamate concentrations were measured, and histological, signaling protein contents, and mRNA expression analyses were performed. Results: Supplementation with free L-glutamine increased the glutamine concentration in the EDL muscle in the C group. The glutamate concentration was augmented in the EDL muscles from T rats. The EDL muscle mass did not change, but a significant rise was reported in the cross-sectional area (CSA) of the fibers in the three experimental groups. The levels of the phosphorylated proteins (pAkt/Akt, pp70S6K/p70S6K, p4E-BP1/4E-BP1, and pS6/S6 ratios) were significantly increased in EDL muscles of G rats, and the activation of p4E-BP1 was present in T rats. The fiber CSAs of the EDL muscles in T, G, and GT rats were increased compared to the C group. These changes were accompanied by a reduction in the 26 proteasome activity of EDL muscles from T rats. Conclusion: Five weeks of GS and/or RET induced muscle hypertrophy, as indicated by the increased CSAs of the EDL muscle fibers. The increase in CSA was mediated via the upregulated phosphorylation of Akt, 4E-BP1, p70S6k, and S6 in G animals and 4E-BP1 in T animals. In the EDL muscles from T animals, a decrease in proteasome activity, favoring a further increase in the CSA of the muscle fibers, was reported.
RESUMO
The aim of this study was to explore the efficacy of intravesical Thalidomide (immunomodulatory, anti-inflammatory and anti-angiogenic) added to BCG using an immune competent autochthonous orthotopic NMIBC animal model. Female Fischer 344 rats, 7 weeks of age, received every 2 weeks for four times, a dose of 1.5 mg/kg of N-methyl-N-nitrosourea (MNU) intravesically. The rats were randomized into four groups (n = 10 per group) to receive intravesical treatment once a week for 6 weeks as follows: control (0.2 ml vehicle), BCG (2 × 106 CFU of Connaught strain in 0.2 ml), Thalidomide (20 mg/kg in 0.2 ml) and BCG-Thalidomide in 0.2 ml. At week 15, bladders were collected for histopathology, cell turnover index by immunohistochemistry and immunoblotting quantification of 4E-BP1 and p70S6K1 for downstream mTOR proliferation signaling and HIF and VEGF for angiogenesis pathway. Thalidomide-BCG association showed a trend for normal histopathology and down-regulation of cell turnover, p70S6K1, HIF-1 and VEGF. 4E-BP1 was up-regulated by treatment, especially in the Thalidomide groups, supporting that its regulation occurs independently of p70S6K1 on mTOR pathway in NMIBC. Intravesical BCG-Thalidomide might represent a significant increment in NMIBC treatment, suggesting p70S6K1, HIF-1 and VEGF as potential molecular target candidates in a clinically relevant immune competent NMIBC model.