MG53基因敲除对小鼠延迟性肌肉酸痛期骨骼肌损伤的影响

关键词：基因敲除  延迟性肌肉酸痛  骨骼肌  损伤

Keywords:gene knockout  delayed onset muscle damage  skeletal muscle  damage

摘要：

      摘要 目的：探讨MG53敲除对骨骼肌损伤的影响，研究MG53在延迟性肌肉酸痛期是否具有减轻骨骼肌膜损伤的作用。方法：8周龄雄性C57小鼠84只，根据基因型分为两大组，野生型（WT）组和敲除型（KO）组，每一大组按照取材时间点又分为7个小组，共14组，即WT组（WC、WE0、WE2、WE12、WE24、WE48、WE72）和KO组（KC、KE0、KE2、KE12、KE24、KE48、KE72），每组6只。在离心运动后相应时间点内眦取血，脱颈处死小鼠，取左腿股直肌用于Western blot实验，右侧用于形态学观察。全自动生化分析仪检测血清肌酸激酶（CK），透射电镜观察14个组大鼠骨骼肌超微结构的变化，Western blot检测MG53蛋白水平。 结果：KE0和KE2组CK较安静组非常显著性升高（P＜0.01），KE24和WE0组CK较安静组显著升高（P＜0.05），同一时间点CK值相比，KE0较WE0显著升高，KE24较WE24显著升高（P＜0.05）；骨骼肌超微结构随时程变化较为明显，KO组在运动后损伤较WT组更为严重，呈现出损伤早、恢复慢的特点，KE24损伤最为严重，且KE72仍然没有恢复到安静水平；WT组MG53蛋白在运动后即刻达到峰值并显著高于安静组（P＜0.05），在24h出现第二次升高（P＜0.05）。 结论：离心运动后KO组小鼠骨骼肌损伤较WT组更为严重，表明MG53能够明显减轻骨骼肌在延迟性肌肉酸痛期的损伤，WT组MG53蛋白在离心运动后即刻和24h显著升高，提示其在延迟性肌肉酸痛期骨骼肌损伤的修复中发挥了重要作用。

Abstract:

      Abstract Objective: To discuss the effect of knock-out MG53 on skeletal muscle, and to determine whether MG53 can protect skeletal muscle from injury during delayed onset muscle damage(DOMS). Method: Eighty-four eight-week old C57 mice were divided into two groups due to their gene (WT and KO), and each group were divided into 7 subgroups again. 14 groups, 6 mice in each. They were WC, WE0, WE2, WE12, WE24, WE48, WE72 and KC, KE0, KE2, KE12, KE24, KE48, KE72. At each time point after 3 days eccentric exercise, the mice were decapitated after drawing blood. The rectus femoris of left leg was used to detect the level of MG53 with Western blot, the other side were used to do electron microscope analysis. Blood CK were measured also. Result:The CK of K0 raised remarkably and decreased gradually until W 12. But the second peak appear at W24 and decreased again gradually since then. Ultrastructural changes of skeletal muscle after eccentric exercise at different time points is obvious. The injury is worsen gradually from Wo to W24, and improved gradually from W48 to W72. Comparing with W groups, the injury in K group were even worsen an each time point. The MG53 of W0 and W24 were 16% and 11% higher than those before exercise （p<0.05）and restored to normal in 72 hours after exercise. Conclusion: The injury after severe exercise is more severity in MG53 knock-out mouse than those in wild mouse. and the MG53 protein increased significantly. It suggests that MG53 may significantly relieve the skeleton muscle injury in delayed muscle sore period.