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目的 探讨热休克蛋白 - 70 (HSP70 )基因在缺氧缺血新生大鼠脑内的表达及地塞米松 (DEX)对其影响。方法 通过建立新生大鼠缺氧缺血性脑病动物模型 ,应用快速竞争性RT PCR技术 ,分别对缺氧缺血(HI) ,DEX预处理后予缺氧缺血 (DH) ,缺氧结束后即刻予DEX (HD) ,DEX加假手术 (DS) ,正常对照 (NS)五组动物的实验侧大脑组织中HSP70mRNA的表达进行半定量分析。结果 缺氧缺血后新生大鼠脑内HSP70mRNA的表达明显增强 ,其表达高峰 (3.86 8± 1.42 1)位于HI后 12h左右 ,并在 12～ 48h内维持较高水平 (3.186±0 .80 3,2 .5 6 8± 0 .70 9)。DEX预处理可使HSP70mRNA的表达明显下降或几乎完全被抑制 ,其 12h ,2 4h ,48h分别为 0 .5 2 6± 0 .5 93,0 .492± 0 .45 0 ,0 .434± 0 .42 8。HI后给予DEX对HSP70mRNA的表达则无明显影响。其12h ,2 4h ,48h分别为 3.46 0± 1.30 9,3.0 2 0± 0 .5 6 5 ,2 .2 42± 0 .5 0 4。结论 DEX预处理可抑制HI对HSP70mRNA过表达的诱导。推测DEX预处理后使HSP70mRNA的表达下降 ,可能与DEX抑制了神经元的过度兴奋有关。
Objective To investigate the expression of heat shock protein 70 (HSP70) gene in brain of hypoxic-ischemic neonatal rats and the effect of dexamethasone (DEX) on it. Methods The animal models of hypoxic-ischemic encephalopathy were established in neonatal rats. Rapid hypoxia-ischemia (HI) and hypoxia-ischemia (DH) preconditioning were performed by rapid competitive RT-PCR. Immediately to the DEX (HD), DEX plus sham surgery (DS), normal control (NS) five experimental animals in the experimental side of the expression of HSP70mRNA semi-quantitative analysis. Results The expression of HSP70 mRNA in hypoxic-ischemic neonatal rat brain increased significantly (3.86 8 ± 1.42 1) at 12 h after HI and maintained at a high level within 12-48 h (3.186 ± 0.80 3 , 2.56 8 ± 0.70 9). DEX pretreatment can significantly reduce the expression of HSP70mRNA or almost completely inhibited at 12h, 24h, 48h respectively, 0.526 ± 0.593, 0.492 ± 0.450, 0.434 ± 0 .42 8. HI after giving DEX HSP70 mRNA expression had no significant effect. The 12h, 24h, 48h were 3.46 ± 1.30 9,3.0 20 ± 0.56 5,2.242 ± 0 .504, respectively. Conclusion DEX pretreatment can inhibit the induction of HSP70mRNA over-expression by HI. Presumably DEX pretreatment decreased the expression of HSP70mRNA, which may be related to DEX inhibiting neuronal over-excitement.