Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an Shaanxi 710069, China.
Shaanxi Key Laboratory for Animal Conservation, Shaanxi Institute of Zoology, Xi'an Shaanxi 710032, China.
J Exp Biol. 2021 Jan 18;224(Pt 2):jeb231639. doi: 10.1242/jeb.231639.
We previously showed that different skeletal muscles in Daurian ground squirrels () possess different antioxidant strategies during hibernation; however, the reason for these varied strategies remains unclear. To clarify this issue, we studied REDD1, FOXO4, PGC-1α, FOXO1 and atrogin-1 proteins to determine the potential cause of the different antioxidant strategies in Daurian ground squirrels during hibernation, and to clarify whether different strategies affect atrophy-related signals. Results showed that the soleus (SOL) muscle experienced intracellular hypoxia during interbout arousal, but no oxidative stress. This may be due to increased PGC-1α expression enhancing antioxidant capacity in the SOL under hypoxic conditions. Extensor digitorum longus (EDL) muscle showed no change in oxidative stress, hypoxia or antioxidant capacity during hibernation. The FOXO1 and PGC-1α results strongly suggested differentially regulated fuel metabolism in the SOL and EDL muscles during hibernation, i.e. enhanced lipid oxidation and maintained anaerobic glycolysis, respectively. Atrogin-1 expression did not increase during hibernation in either the SOL or EDL, indicating that protein synthesis was not inhibited by atrogin-1. Thus, our results suggest that different fuel regulation may be one mechanism related to antioxidant defense strategy formation in different kinds of skeletal muscle fibers of Daurian ground squirrels during hibernation.
我们之前曾表明，达乌尔黄鼠（）不同的骨骼肌在冬眠期间具有不同的抗氧化策略；然而，这些不同策略的原因仍不清楚。为了阐明这个问题，我们研究了 REDD1、FOXO4、PGC-1α、FOXO1 和 atrogin-1 蛋白，以确定达乌尔黄鼠在冬眠期间不同的抗氧化策略的潜在原因，并阐明不同的策略是否会影响与萎缩相关的信号。结果表明，在间歇觉醒期间，比目鱼肌（SOL）经历了细胞内缺氧，但没有氧化应激。这可能是由于 PGC-1α 表达增加，在缺氧条件下增强了 SOL 的抗氧化能力。在冬眠期间，趾长伸肌（EDL）肌肉没有发生氧化应激、缺氧或抗氧化能力的变化。FOXO1 和 PGC-1α 的结果强烈表明，在冬眠期间，SOL 和 EDL 肌肉中燃料代谢存在差异调节，即分别增强脂质氧化和维持无氧糖酵解。在 SOL 和 EDL 中，atrog in-1 的表达在冬眠期间均未增加，表明蛋白合成未被 atrog in-1 抑制。因此，我们的结果表明，不同的燃料调节可能是达乌尔黄鼠不同类型骨骼肌纤维在冬眠期间形成抗氧化防御策略的相关机制之一。
