大鼠胸部严重创伤后早期下丘脑CRH表达的实验研究

目的 探讨大鼠胸部撞击伤应激反应中，下丘脑表达和分泌促肾上腺皮质激素释放激素(CRH)的变化规律及其反馈调节机制。方法 应用BIM-Ⅲ型多功能小型生物撞击机致伤动物，采用免疫组化和RT-PCR等技术，检测大鼠下丘脑CRH的分布及含量变化规律。分组：对照组、撞击伤后15、30、60、120、360、720分钟组、撞击伤处理组(用CRH1R特异性阻滞剂CP-154526处理)。结果 正常情况下，CRH少量分布于下丘脑室旁核和视上核；撞击伤后，室旁核和视上核的CRH染色明显增加；撞击伤后60分钟，下丘脑CRH mRNA含量明显增加，且呈逐渐增加的趋势，720分钟开始回落；用CP-154526处理的大鼠，撞击伤后，下丘脑CRH含量的增加明显减少。结论 在创伤性应激反应早期，CRH通过与下丘脑神经元CRH1R的结合，选择性地调节下丘脑神经元CRH基因的表达。

Effect of severe traumatic injury on expression of corticotropin-releasing hormone in the hypothalamus of rat

Objective To investigate the function and expression of corticotropin releasing hormone (CRH) in the hypothalamus after severe traumatic chest injury in rat. Methods Rats were injuried,deeply anesthetized,and killed before (control) and 15,30,60,120,360 and 720 min,after traumatic lung injury. Using immunohistochemistry and RT PCR,we examined the time course of changes in CRH concentrations in the hypothalamus of male Wistar rats. Results CRH is present in paraventricular nucleus (PVN) and supraoptic nucleus (SON) of hypothalamus. In response to severe traumatic chest injury,a significant increase in CRH mRNA level was noted 60 min after trauma. It then gradually decreased at 720 min after trauma. CP 154526 could significantly inhibit the expression of CRH. Conclusion CRH from the PVN and SON are involved in control of the synthesis and release of CRH from hypothalamus after severe traumatic lung injury,suggesting a role of CRH type 1 receptor in the activation of CRH gene expression.