大鼠脑液压伤后磷脂酶A_2与糖皮质激素受体的变化

Changes of PLA_2,GR and Water-content after Cerebral Contusion in Rats

目的:观测鼠脑外伤后局部组织、磷脂酶A_2(PLA_2)、糖皮质激素受体(GR)脑含水量变化。方法:应用鼠脑液压伤动物模型,采用GR放射配基结合分析法和PLA_2快速测定法,测定伤侧鼠脑组织PLA_2、GR和脑含水量变化。结果:伤后1h PLA_2增加,12～24h形成高峰,随之缓慢减少直至72h。GR伤后6～12h明显减少,72h恢复至对照组70%水平。脑含水量伤后6h逐渐上升。结论:(1)创伤后脑缺血脑水肿是PLA_2高张力的基础。(2)GR减少是PLA_2抑制作用低下的重要因素,早期至72h PLA_2与GR改变呈负相关,糖皮质激素(GC)对PLA_2的抑制作用与GR水平密切相关。(3)早期大剂量应用地塞米松(DEX)对于降低PLA_2,促进GR恢复,减轻脑水肿有显著疗效。

Objective:To investigate the relative changes of PLA2 activity,GR,and water-content in local cerebrum after injury. Methods:PLA2 activity,GR and water-content in cerebrum on the injured side were detected using a model of fluid perfus-sion injured rat brain. Results: PLA2 increased 1 hour after injury, then get the peak at 12 ~ 24 hours, and gradually decreased 72 hours after injury. GR significantly decreased at 6~12 hours,and came back to 70% of the eontrol group level 72 hours after injury. Water-content gradually increased at 6 hours after injury. Conclusion:The pathological rising of PLA2 activity is relative to cerebral ischemia and cerebral edema on the injured side of the brain. The change of GR plays an impor- tant role in low suppressive effect of PLA2 . There was a negative correlation between PLA2 and GR from early stage to 72 hours after injury. The suppressive effect of glucocorticoid (GC) to PLA2 is relative to GR. The treatment of high dose of DEX at early stage of injury can effectively decrease cerebral edema.