甲基强地松龙对大鼠脊髓损伤后热休克蛋白70表达的影响

目的 探讨大剂量甲基强地松龙㈣对大鼠脊髓损伤后脊髓内热休克蛋白70(HSP70)表达的影响.方法 125只SD大鼠按随机数字表法分为五组:单纯手术组30只、MP对照组30只、脊髓损伤组30只、MP治疗组30只、空白对照组5只,在实验开始后6个时间点:2h、6 h、12h、24h、48 h、72h(空白对照组任选一个时间点)取出脊髓标本进行脊髓病理形态学观察.并通过免疫组化染色法检测脊髓组织中HSP70的表达.结果 使用MP治疗后,大体标本及HE染色观察显示脊髓的继发性损伤减轻.免疫组化染色显示:空白对照组和MP对照组的脊髓组织中基本没有HSP70的表达:单纯手术组各时间点见少量HSP70表达;脊髓损伤组损伤后2h脊髓组织内出现HSP70的表达,损伤后24 h脊髓组织中HSP70表达达到高峰,并维持至损伤后72 h,HSP70表达主要出现在脊髓灰质的神经细胞和胶质细胞中;MP治疗组脊髓组织中HSP70的表达在所有的时间点较脊髓损伤组明显增强,差异有统计学意义(P<0.05),表达高峰提前至12h.同时脊髓白质神经纤维网内也可见HSP70的表达.结论 大剂量MP可以显著增强损伤的脊髓组织中HSP70的表达,提前其表达高峰时间,扩大其表达范围.通过诱导损伤后脊髓组织大量表达HSP70可能是MP保护脊髓的作用机理之一.

Effect of methylprednisolone on expression of heat shock protein 70 following injury of spinal cord in rats

Objective To study the effect ofmethylprednisolone (MP) on the expression of heatshock protein 70 (HSP70) following the injury of spinal cord (SC1) in rats. Methods 125 SD rots wererandomly divided into 5 groups: the simple operation group (n=30), the MP control group (n=30), theinjury group (n=30), the MP treatment group (n=30) and the normal control group (n=5). Specimen of thespinal cord were collected at 2, 6, 12, 24, 48, 72 h after SCI, respectively. Their pathomorphology wasobserved and HSP70 expression was detected by immunohistochemistry. Results After treatment ofMP, the secondary injury was lightened, according to the HE staining of the specimen.lmmunohistochemistry revealed that there were no HSP70 expression in the normal control group and theMP control group, that there was a little HSP70 in the simple operation group, and that there was a lot ofHSP70 in the injury group 2 h after injury, and the expression peaked at 24 h and maintained to 72 h afterinjury. The expression was significantly increased and the peak of expression was in advance in the MPtreatment group as compared with injury group, and it was also found in neuropil of white substance ofspinal cord. Conclusion High-dose NIP can obviously increase the expression of HSP70 in injuredspinal cord, and has the peak time of expression in advance, and enlarge the scope of expression. It maybe one of the mechanism to protect the spinal cord that MP guide myeloid tissue to overexpress HSP70after spinal cord injury.