甲基强的松龙对大鼠脊髓缺血再灌注损伤后钙蛋白酶表达的影响

The influence of methylprednisolone on the expression of calpain in the ischemia-reperfusion spinal cord injury in rat

目的:观察大鼠脊髓缺血再灌注损伤后应用甲基强的松龙(MP)对脊髓组织钙蛋白酶表达的影响。方法:用纯种雄性成年SD大鼠,夹闭右肾动脉分支下腹主动脉30min后恢复血供,缺血再灌注组(损伤组)不作任何治疗,造成动物脊髓缺血再灌注损伤模型,治疗组于恢复血供后即刻静脉应用MP(治疗组),观察再灌注后3h、24h、72h和7d时脊髓损伤节段钙蛋白酶Ⅰ的表达以及钙蛋白酶特异性底物68-KDNFP的降解。结果:脊髓再灌注后3h出现钙蛋白酶Ⅰ阳性细胞和68-KDNFP的降解产物,随着时间的延长,阳性细胞数目逐渐增多,染色深度逐渐增加,再灌注后72h最明显,MP治疗组较损伤组明显降低(P<0.01)。结论:脊髓再灌注损伤后静脉应用MP可以减少大鼠脊髓中calpain-Ⅰ阳性细胞的表达,对细胞骨架蛋白68-KDNFP具有明显保护作用。证实MP可以抑制钙蛋白酶的表达,可能是MP对脊髓损伤治疗的另一种机理。

Objective：To observe the effective of methylprednisolone to the expression of calpain in rat spinal cord after ischemia-reperfusion injury.Method：The abdomial aorta of male Sprague-Dawley （SD） rats were clipped for 30 minutes to form the ischemia-reperfusion spinal cord injury model,and then some of them treated with intravenous of methylprednisolone （test group）.3h,24h,72h or 7d later,the expression of calpain-Ⅰ in the attached segment of spinal cord was indicated with immunohistochemistry stain.Western Blot analysis of 68-KD NFP was used to indicate the activity of calpain.Result：The immunohistochemistry stain of calpain-Ⅰ was found and 68-KD NFP was degradated in the spinal cord sections after 3h of reperfusion and peaked after 72h.In the methylprednisolone treated groups,the expression of calpain-Ⅰ was inhibited.Statistically analysis showed significant differences between the control group and the treated groups （P〈0.01）.Conclusion：Postinjury interverous of methylprednisolone in rat spinal cord after ischemia-reperfusion can inhibit early increased calpain-Ⅰ expression and protect the frame protein.h may be a new mechanism of methylprednisolone in treating spinal cord injury.