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.