藏羚羊与藏绵羊心肌、骨骼肌中肌红蛋白含量和乳酸脱氢酶活性的比较

为了探讨藏羚羊(Pantholops hodgsonii)对低氧环境的适应机制。以生活在同海拔(4 300 m)的藏绵羊(Tibetan Sheep)为对照,用分光光度法测定2种动物心肌、骨骼肌中肌红蛋白(myoglobin,Mb)含量、乳酸(lactic acid,LD)含量及乳酸脱氢酶(lactate dehydrogenase,LDH)活力。结果显示,藏羚羊心肌和骨骼肌中Mb含量明显高于藏绵羊(P0.05),但心肌和骨骼肌的Mb含量无差别(P0.05),而藏绵羊心肌Mb含量明显高于骨骼肌(P0.05);藏羚羊心肌和骨骼肌中LD含量及LDH活力明显低于藏绵羊(P0.05),且2种动物心肌中的LDH活力均明显低于其骨骼肌(P0.01)。结果表明,藏羚羊尽管生活在高寒缺氧地区,其心肌和骨骼肌细胞仍然能得到丰富的氧供应,并非处于缺氧状态,这可能是通过增加心肌和骨骼肌中Mb的含量,提高其在低氧环境获取和储存氧的能力,从而提高有氧获能水平。与之相反,藏绵羊尽管也生活在高寒缺氧地区,但其心肌和骨骼肌中Mb含量相对于藏羚羊较低,且LD含量和LDH活力较高,说明其心肌和骨骼肌细胞内氧供不如藏羚羊丰富,提示藏绵羊可能主要以糖酵解获能。我们推测这种差异可能与两种动物不同的运动习性密切相关,且认为藏羚羊较高的Mb含量可能是其适应高原缺氧条件的分子基础之一。

Comparison on the Myoglobin Contents and Lactate Dehydrogenase Activity in Cardiac and Skeletal Muscles between Tibetan Antelope and Tibetan Sheep

To explore the adaptive mechanism to hypoxia in Tibetan Antelope (Pantholops hodgsonii), we compared the contents of myoglobin (Mb), lactic acid (LD) and the activity of lactate dehydrogenase (LDH) in cardiac and skeletal muscles by spectrophotometry in Tibetan Antelope and Tibetan Sheep from the same elevation . The results showed that the contents of Mb in cardiac and skeletal muscles of Tibetan Antelope were significantly higher than in Tibetan Sheep (P<0.05), while no significant difference was observed between cardiac and skeletal muscles in Tibetan Antelope (P>0.05). However, the content of Mb in cardiac was significantly higher than that in skeletal muscle in Tibetan Sheep (P<0.05). The contents of LD and the activity of LDH in cardiac and skeletal muscles of Tibetan Antelope were significantly lower than in Tibetan Sheep (P<0.05), and the activity of LDH in cardiac muscle was significantly lower than that in skeletal muscle in the two groups. The results suggest that Tibetan Antelope could improve its ability to obtain and store oxygen under hypoxia by increasing the contents of Mb in cardiac and skeletal muscles,so that its cardiac and skeletal muscles could be supplied with rich oxygen in hypoxic environment. On the contrary, Tibetan Sheep is also a hypoxia-adapted species; it has less Mb, but higher LD content and LDH activity in cardiac and skeletal muscles, suggesting that it may obtain most energy from aerobic oxidation. Therefore, we speculate the above-mentioned differences might be related to different sports capabilities of two hypoxia-adapted species, and we consider that higher Mb content in Tibetan Antelope might be one of the molecular mechanisms for hypoxia adaption.