孕酮对大鼠脑损伤后大脑皮质及海马CA1区环氧合酶-2和诱导型一氧化氮合酶表达的影响

Effects of progesterone treatment on cyclooxygenase-2 and iNOS in the cerebral cortex and hippocampus CA1 after traumatic brain injury in rat

目的： 观察孕酮对大鼠脑损伤后皮质及海马CA1区COX-2和iNOS表达的影响.方法： 雄性SD大鼠随机分为假手术组、脑损伤组和孕酮治疗组,按照改良的Feeney自由落体损伤装置制作大鼠脑损伤模型.孕酮治疗组伤后1h、 6h腹腔注射孕酮16mg/kg.各组于伤后24h取材.用免疫组织化学法及免疫蛋白印迹法,观察大鼠皮质及海马CA1区COX-2、iNOS的免疫阳性细胞数和蛋白表达水平变化.结果： 与假手术组大鼠相比,脑损伤组大鼠皮质及海马CA1区COX-2、 iNOS阳性细胞数和蛋白表达水平较假手术组增加;孕酮治疗组与脑损伤组比较,大鼠皮质及海马CA1区COX-2、 iNOS阳性细胞数和蛋白表达水平减少,差异有统计学意义.结论： 孕酮可能通过降低COX-2、 iNOS的表达发挥脑损伤保护作用.

Objective： To investigate effects of progesterone treatment on cyclooxygenase-2 （COX-2） and iNOS in the cerebral cortex and hippocampus CA1 after traumatic brain injury in rats. Methods： （PRO（3） Male Spraque-Dawley rats were randomlydivided into 3 groups： sham-operated group （n = 15）, TBI group （n = 15） and PROCj-treated group （n = 15）. The rat model of TBI was duplicated with the improved Feeney＇s method. Progesterone in the PROG-treated group was given i. p. at 1 h and 6 h after iniury. The rats were sacrificed respectively in three groups at 24 h after injury. The changes of the positive cell numbers and protein level of COX2 and iNOS in the cortex and hippocampus CA1 were examined by immuno- histochemistry and Western blotting, Results： The positive cell numbers and protein level of COX-2 and iNOS in the cortex and hippocampus CA1 of the TBI group were distinctly higher than those of the sham-operated group. The positive cell numbers and protein level of COX-2 and iNOS in the cortex and hippocampus CA1 of the PROG-treated group were distinctly lesser than those of the TBI group. There were significant differences between the TBI group and the PROG-treated group in the positive cell numbers and protein level of COX-2 and iNOS in the cortex and hippocampus CA1 at 24 h after injury. Conlusion ： The protective effect of progesterone on traumatic brain injury may be induced by down-regulation of COX-2 and iNOS expression.