大剂量甲基强的松龙对大鼠急性脊髓损伤后Caspase-9mRNA及HSP27mRNA表达的影响

Effect of high-dose methylprednisolone on expressions of Caspase-9 mRNA and heat shock protein 27 mRNA after acute spinal cord injury in rats

目的通过对大剂量甲基强的松龙（MP）对大鼠急性脊髓损伤（ASCI）后Caspase-9mRNA及热休克蛋白27（HSP27）mRNA表达影响的观察，探讨MP治疗ASCI的作用机制。方法选用72只大鼠，建立ASCI模型，应用原位杂交技术研究MP组和生理盐水（NS）组在伤后1、3、6h和1、2、3d脊髓组织中Caspase-9 mRNA、HSP27mRNA的动态变化。结果MP组与Ns组脊髓损伤组织中存在Caspase-9 mRNA、HSP27mRNA的阳性表达。ASCI后Caspase-9 mRNA表达增加，6h最为显著（12．26±2．09），MP组除1h组外（P〉0．05），在伤后各时间点的表达明显低于Ns组（P〈0．01）；ASCI后HSP27 mRNA表达增加，1d最为显著（11．40±1．52），MP组除1h组外（P〉0．05），在伤后各时间点的表达明显高于Ns组（P〈0．01）。结论MP对ASCI的治疗有效，其机制可能是通过促进HSP27合成从而抑制Caspase-9的合成实现的。

Objective To discuss the effect and the mechanism of high-dose methylprednisolone （MP） on the expressions of caspase-9 mRNA and heat shock protein27 （HSP27）mRNA after acute spinal cord injury （ASCI）in Cats. Methods After ASCI model were established , the rats were treated with MP （ MP group） or normal saline （ NS group）. The expressions of caspase-9 mRNA and HSP27 mRNA were determined by in situ hybridization at different time points. Results The expressions of caspase-9 mRNA and HSP27 mRNA in spinal cord tissues were positive in both NS group and MP group （ 12. 26 ± 2. 09 ）. The expression of caspase-9 mRNA increased after ASCI, and reached peak 6 hours after ASCI. The expression of caspase-9 mRNA in MP group was significantly lower than that in NS at each time point after ASCI（ P 〈 0. 01 ）except for the 1 st hour time point. The expression of HSP27mRNA increased after ASCI and reached the peak 1 day after ASCI （ 11.40 ± 1.52）. The expression of HSP27mRNA in MP group was significantly higher than that in NS group at each time point after ASCI（ P 〈 0. 01 ）except for the 1st hour time point. Conclusion MP could inhibit the expression of caspase-9 and stimulate the expression of HSF27. Thus, it is effective in treating ASCI.