Department of Exercise Physiology, Karaj Branch, Islamic Azad University, Karaj, Iran.
Basic Medical Science Research Center, Histogenotech Co, Tehran, Iran.
Gene. 2023 Jan 20;850:146955. doi: 10.1016/j.gene.2022.146955. Epub 2022 Oct 8.
The present research aims to evaluate the effect of swimming exercise and chitosan-coated l-arginine on mitochondrial oxidation, BCL2 Interacting Protein 3 (Bnip3), NIP-like protein × (Nix), B-cell lymphoma-extra-large (Bcl-xL) and autophagy-related protein light chain 3(LC3) expression in soleus muscle of aging rats. In this experimental research, 25 male Wistar rats were assigned into five groups randomly: young, old, old + Nano l-arginine (Nano L-a), old + exercise (Ex), and old + Nano l-arginine (Nano L-a) + exercise (Ex) (n = 5 in each). They performed a swimming exercise program five days a week for six weeks. To determine the relative strength for rats before and after performing these interventions, the 1repetition maximum (1RM) test was done as a pre and post-test. The exercise program started with 20 min and after four sessions, gradually increased to 60 min and this time was maintained until the completion of the training period. l-arginine coated with chitosan nanoparticles was given to the rats in the l-arginine-supplemented group via gavage at a dosage of 500 mg/kg/day, five days a week, for six weeks. Additionally, the rats in all groups were fed a normal diet (2.87 kcal/g and 15 % energy from fat). Upon the completion of the protocol implementation, the rats were sacrificed and the soleus muscle was fixed and frozen to determine hematoxylin and eosin (H&E) staining, immunohistochemistry (IHC), gene expression analysis, levels of reactive oxygen species (ROS), and total antioxidant capacity (TAC). The results from the present research indicated that swimming exercise and Nano l-arginine improve the strength and histology of muscle tissue in old rats (p < 0.05). Aging significantly increased the expression of Nix and Bnip3 (p < 0.05) and reduced the Bcl-xL gene expression (p < 0.05). The expression of LC3 protein also increased with aging (p < 0.05). Therapeutic interventions, such as combined treatment (old + Nano L-a + Ex) for old animals, reduced the amount of this protein in soleus muscle (p < 0.05). The ROS values also showed a significant reduction only in the old + Nano L-a + Ex group compared to the old group. Moreover, TAC values show a significant decrease in the old and old + Ex groups in comparison to the young group. The use of arginine supplement, especially in nano form, along with swimming exercise seems to reduce the oxidative damage to the elderly muscle tissue, which has a positive effect on the structure and function of the soleus muscle. Since these interventions only had a significant effect on LC3 protein, further studies with more diverse measurement methods for autophagy are suggested.
本研究旨在评估游泳运动和壳聚糖包裹的 l-精氨酸对衰老大鼠比目鱼肌中线粒体氧化、BCL2 相互作用蛋白 3（Bnip3）、NIP 样蛋白×（Nix）、B 细胞淋巴瘤-extra-large（Bcl-xL）和自噬相关蛋白 light chain 3（LC3）表达的影响。在这项实验研究中，将 25 只雄性 Wistar 大鼠随机分为五组：年轻组、老年组、老年+纳米 l-精氨酸（Nano L-a）组、老年+运动（Ex）组和老年+纳米 l-精氨酸（Nano L-a）+运动（Ex）组（每组 5 只）。它们每周进行五天的游泳运动，共六周。为了确定干预前后大鼠的相对力量，进行了 1 次重复最大（1RM）测试作为预测试和后测试。运动方案从 20 分钟开始，经过四节课后，逐渐增加到 60 分钟，并保持到训练期结束。壳聚糖包裹的 l-精氨酸以 500mg/kg/天的剂量通过灌胃给予 l-精氨酸补充组的大鼠，每周五天，共六周。此外，所有组的大鼠均喂食正常饮食（2.87kcal/g 和 15%能量来自脂肪）。在完成方案实施后，处死大鼠，固定并冷冻比目鱼肌，以确定苏木精和伊红（H&E）染色、免疫组织化学（IHC）、基因表达分析、活性氧（ROS）水平和总抗氧化能力（TAC）。研究结果表明，游泳运动和 Nano l-精氨酸可改善老年大鼠的肌肉力量和组织学（p<0.05）。衰老显著增加了 Nix 和 Bnip3 的表达（p<0.05）并降低了 Bcl-xL 基因表达（p<0.05）。LC3 蛋白的表达也随衰老而增加（p<0.05）。对老年动物的联合治疗（老年+Nano L-a+Ex）等治疗干预措施减少了比目鱼肌中这种蛋白质的含量（p<0.05）。ROS 值仅在老年+Nano L-a+Ex 组与老年组相比显著降低。此外，与年轻组相比，TAC 值在老年组和老年+Ex 组中均显著降低。使用精氨酸补充剂，特别是纳米形式，结合游泳运动，似乎可以减轻老年人肌肉组织的氧化损伤，对比目鱼肌的结构和功能产生积极影响。由于这些干预措施仅对 LC3 蛋白有显著影响，因此建议使用更具多样性的自噬测量方法进行进一步研究。
