The research on the formation mechanism of extraordinary oxidative capacity of skeletal muscle in hibernating ground squirrels (Spermophilus dauricus)
The research on the formation mechanism of extraordinary oxidative capacity of skeletal muscle in hibernating ground squirrels (Spermophilus dauricus)
复制标题
冬眠地松鼠骨骼肌超强氧化能力形成机制的研究
DOI：
10.1186/s40555-015-0124-9
复制
发表时间：
2015-06-01
影响因子：
1.6
通讯作者：
Goswami, Nandu
中科院分区：
文献类型：
--
作者：
Jiang, Shanfeng;Gao, Yunfang;Goswami, Nandu
背景资料：以往的研究表明，冬眠动物，在长期的麻痹条件下，显示出增加的氧化肌纤维（I型）的比例和降低的糖酵解肌纤维（II型）的比例在骨骼肌和伴随着非凡的氧化能力。这一观察结果与非冬眠动物完全相反，非冬眠动物表现出氧化肌纤维（I型）向糖酵解肌纤维（II型）的转变。目前，这些变化发生的机制尚不清楚。为探讨冬眠黄鼠骨骼肌高氧化能力的机制，采用免疫组织化学方法测定了冬眠黄鼠骨骼肌毛细血管密度（CD）和毛细血管/肌纤维（C/F）。采用实时定量PCR法测定缺氧诱导因子-1 α（HIF-1 α）和血管内皮生长因子（VEGF）mRNA表达水平。结果：在比目鱼肌（SOL）中，缺氧诱导因子-1 α（HIF-1 alpha）和血管内皮生长因子（VEGF）的mRNA表达水平在麻痹状态下略有降低，但差异无统计学意义;而在觉醒状态下，HIF-1 α和VEGF的mRNA表达水平显著升高。冬眠动物CD无明显变化，C/F增加15%。CcO在休眠状态下活性最高。在SOL中，冬眠动物和夏季活动动物的HK和PK活性无显著差异。结论：冬眠动物骨骼肌毛细血管供应的增加可能是其氧化能力的保证。
Background: Previous studies indicate that hibernating animals, under conditions of torpor for long periods, show an increased oxidative muscle fibers (type I) ratio and a decreased glycolytic muscle fibers (type II) ratio in skeletal muscle and accompanied by extraordinary oxidative ability. This observation is completely contrasted with non-hibernators, which show a shift of oxidative muscle fibers (type I) to glycolytic muscle fibers (type II). Presently, the mechanisms by which these changes occur remain unclear. To investigate the mechanism of high oxidative capacity of the skeletal muscles in hibernating ground squirrels, capillary density (CD), and capillary/fiber (C/F) were measured by immunohistochemistry. mRNA expression levels of hypoxia-inducible factor-1 alpha (HIF-1 alpha) and vascular endothelial growth factor (VEGF) were determined using real-time quantitative PCR assay. Spectrophotometry was applied to determine the activities of hexokinase (PK), pyruvate kinase (HK), and cytochrome c oxidase (CcO).Results: In the soleus muscle (SOL), mRNA expression levels of HIF-1 alpha and VEGF in torpor became slightly lower but were not statistically significant; they were, however, significantly higher in the arousal group. In hibernating animals, no significant change occurred in CD but C/F increased by 15 %. CcO showed the highest activity in torpor. There were no significant differences in the activities of HK and PK between the torpid animals and summer active animals in SOL. However, PK activity increased by 34 % after hibernation.Conclusions: Oxidative capacity may be ensured by an increase of capillary supply of skeletal muscle in hibernating animals.