Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600 - prédio anexo - CEP 90035-003 - Porto Alegre, RS, Brazil.
Appl Physiol Nutr Metab. 2017 Nov;42(11):1192-1200. doi: 10.1139/apnm-2017-0193. Epub 2017 Jun 28.
The use of dietary supplements to enhance the benefit of exercise training is a common practice. The liver is the organ where all substances are metabolized, and certain supplements have been associated with liver injury. Vitamin A (VA), a liposoluble vitamin stored in the liver, is commonly used as an antioxidant supplement. Here, we evaluated the effect of chronic VA supplementation on oxidative damage and stress parameters in trained rats. Animals were divided into the following groups: sedentary (SE), sedentary/VA (SE+VA), exercise training (ET), and exercise training/VA (ET+VA). During 8 weeks, animals were subjected to swimming (0%, 2%, 4%, 6% body weight) for 5 days/week and a VA daily intake of 450 retinol equivalents/day. Parameters were evaluated by enzymatic activity analysis, ELISA, and Western blotting. VA caused liver lipid peroxidation and protein damage in exercised rats and inhibited the increase in HSP70 expression acquired with exercise alone. The ET group showed higher levels of antioxidant enzyme activity, and VA inhibited this adaptation. Expression of the pro-inflammatory cytokines, interleukin (IL)-1β, and tumor necrosis factor-α was reduced in the ET+VA group, while the anti-inflammatory cytokine, IL-10, was increased. Western blotting showed that both exercised groups had lower levels of the receptor for advanced glycation end products, suggesting that VA did not affect this receptor. Our study demonstrated that, although VA caused oxidative damage, a controlled administration might exert anti-inflammatory effects. Further studies with higher VA doses and longer ET interventions would elucidate more the effects of the supplementation and exercise on liver parameters.
使用膳食补充剂来增强运动训练的效果是一种常见的做法。肝脏是所有物质代谢的器官，某些补充剂与肝损伤有关。维生素 A（VA）是一种脂溶性维生素，储存在肝脏中，通常用作抗氧化补充剂。在这里，我们评估了慢性 VA 补充对训练大鼠氧化损伤和应激参数的影响。动物分为以下几组：久坐（SE）、久坐/VA（SE+VA）、运动训练（ET）和运动训练/VA（ET+VA）。在 8 周内，动物进行游泳（0%、2%、4%、6%体重），每周 5 天，每天摄入 VA 450 视黄醇当量。通过酶活性分析、ELISA 和 Western blot 评估参数。VA 导致运动大鼠肝脏脂质过氧化和蛋白质损伤，并抑制了单独运动引起的 HSP70 表达增加。ET 组表现出更高的抗氧化酶活性，VA 抑制了这种适应。在 ET+VA 组中，促炎细胞因子白细胞介素（IL）-1β和肿瘤坏死因子-α的表达减少，而抗炎细胞因子 IL-10 的表达增加。Western blot 显示，两个运动组的晚期糖基化终产物受体水平较低，表明 VA 不影响该受体。我们的研究表明，尽管 VA 引起氧化损伤，但控制剂量可能会发挥抗炎作用。进一步研究更高剂量的 VA 和更长时间的 ET 干预将更清楚地阐明补充剂和运动对肝脏参数的影响。
