Programa de Pós-Graduação em Ciências do Movimento Humano, Laboratório de Plasticidade Neuromuscular, Universidade Metodista de Piracicaba, Piracicaba, SP, Brasil.
Departamento de Biologia Estrutural e Funcional, Instituto de Biociências de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brasil.
Braz J Med Biol Res. 2022 Jan 5;55:e11597. doi: 10.1590/1414-431X2021e11597. eCollection 2022.
The effect of beta-hydroxy-beta-methylbutyrate (HMB) supplementation associated with exercise training at different intensities and frequencies on skeletal muscle regeneration of muscle-injured rats was investigated. Male Wistar rats were divided into sedentary and trained groups. The sedentary groups were subdivided into non-injured (SED-Ct), non-injured supplemented with HMB (SED-Ct-HMB), injured (SED), and injured with HMB (SED-HMB), and the trained groups were injured, supplemented with HMB, and then divided into training three times a week without load (HT3) or with load (HT3L) and training five times a week without load (HT5) and with load (HT5L). The rats received a daily dose of HMB associated with 60 min of swimming with or without 5% body mass load for 14 days. On the 15th day, cryoinjury was performed in the right tibialis anterior muscle (TA), and 48 h later, supplementation and training continued for 15 days. After the last session, the TA was dissected and a cross-sectional area (CSA) of muscle fibers was used to determine the percentage of CSA fibers and connective tissue (%CT), as well as the total and phosphorylated protein contents. SED-HMB showed increased CSA and decreased %CT and TGF-β when compared to SED. HT3 showed increased CSA and reduced %CT accompanied by increased IGF-1/Akt, myogenin, and MuRF1, and decreased TGF-β. The CSA of HT5L also increased, but at the cost of a higher %CT compared to the other groups. Our results demonstrated that HMB associated with training without load and with lower frequency per week may be a valuable strategy for skeletal muscle regeneration.
研究了不同强度和频率的运动训练与β-羟基-β-甲基丁酸（HMB）补充剂联合使用对肌肉损伤大鼠骨骼肌再生的影响。雄性 Wistar 大鼠被分为安静组和训练组。安静组进一步分为未损伤（SED-Ct）、未损伤补充 HMB（SED-Ct-HMB）、损伤（SED）和损伤补充 HMB（SED-HMB），训练组分为损伤、补充 HMB 后，又分为每周训练 3 次不负荷（HT3）或负荷（HT3L）和每周训练 5 次不负荷（HT5）和负荷（HT5L）。大鼠每天接受 HMB 剂量，同时进行 60 分钟游泳，有或无 5%体重负荷，共 14 天。第 15 天，对右侧比目鱼肌（TA）进行冷冻损伤，48 小时后，继续补充和训练 15 天。最后一次训练后，解剖 TA，测量肌纤维横截面积（CSA），以确定 CSA 纤维百分比和结缔组织百分比（%CT），以及总蛋白和磷酸化蛋白含量。与 SED 相比，SED-HMB 组 CSA 增加，%CT 降低，TGF-β减少。HT3 组 CSA 增加，%CT 降低，同时 IGF-1/Akt、myogenin 和 MuRF1 增加，TGF-β减少。HT5L 组 CSA 也增加，但与其他组相比，%CT 更高。结果表明，无负荷和低频率每周训练与 HMB 联合使用可能是骨骼肌再生的一种有价值的策略。
