骨骼肌损伤与修复中内质网应激蛋白的表达变化

摘要目的：通过观察骨骼肌损伤与修复过程中内质网应激（ERS）蛋白的表达变化，探讨内质网应激在骨骼肌损伤与修复过程中的可能作用。方法：72只8周龄雄性SD大鼠随机分为对照组（C组, n=8）和运动组（E组, n=64）。采用一次性持续90min下坡跑（速度为16m/min，坡度为-16°），分别在运动结束后的0h、6h、12h、1d、2d、3d、1周和2周处死，取大鼠右侧腓肠肌，用于组织学、SOD活性和MDA含量以及内质网应激蛋白GRP78和GADD153表达的测定。结果：①运动后3d骨骼肌大量炎症细胞浸润，损伤程度最为严重，运动后2周肌纤维形态结构基本恢复正常；②SOD的活性运动后即刻上升，之后下降，在1d最低，3d出现第二次下降；MDA的含量运动后即刻上升，之后持续下降，2周时低于对照组水平。SOD/MDA表现为运动后下降，1d最低，之后持续上升。上述变化与对照组相比，均无显著性差异。③内质网应激蛋白GRP78、GADD153的表达以及GRP78/GADD153表现为运动后呈上升趋势，1d时出现第一次峰值，之后略有下降，1周达到最高，2周时出现下降趋势，但仍高于对照组。结论：骨骼肌损伤修复过程中前期内质网应激蛋白的表达增加有利于发挥细胞保护的作用，后期的表达有利于促进骨骼肌损伤后的修复。

Expressions of endoplasmic reticulum stress proteins in skeletal muscle injury and repair

Objective:To confirm the role of endoplasmic reticulum stress(ERS) over the skeletal muscle injury and repair process by investigating the changes of expression of ERS proteins.Method:Seventy-two 8-week-SD male rats were divided into control group(C,n=8) and exercise group(E,n=64).After a bout downhill running of 90min,with 16m/min speed and-16° grade,the rats were sacrificed respectively at 0h,6h,12h,1d,2d,3d,1w,2w post-exercise.The gastrocnemius was fetched for morphology observation,ERS proteins assay and superoxide dismutase(SOD),activity and malondialdehyde(MDA) content test.Result:①Morphology of skeletal muscles showed overt signs of injury at 3d post-exercise with large amount of inflammatory cells.Two weeks post-exercise morphology of myofibers nearly recovered to normal;②SOD activity up-regulated at 0h post-exercise immediately,then decreased to the lowest at 1d followed by the second down at 3d post-exercise.MDA content increased at 0h post-exercise,then decreased,at 2 weeks post-exercise lower than C group.SOD/MDA decreased post-exercise,especially at 24h post-exercise to the lowest,then increased continuously.All the changes had no significant difference compared with C group;③Expressions of ERS proteins GRP78,GADD153 and GRP78/GADD153 increased post-exercise and peaked at 1d at first,then decreased and reached the highest at 1 week post-exercise,then decreased at 2 weeks post-exercise,but was still higher than C group.Conclusion:In skeletal muscle injury and repair early process high expressions of endoplasmic reticulum stress proteins could protect cells and later promote repair and regeneration.