异氟醚对老年大鼠脑组织神经元凋亡的影响

目的 探讨异氟醚对老年大鼠脑组织神经元凋亡的影响.方法 健康雌性老年SD大鼠90只,月龄22～24月,体重497～593 g,随机分为对照组(C组)、1.2%异氟醚组(Ⅰ1组)和1.8%异氟醚组(Ⅰ2组),每组30只.C组吸入含40%O2的空氧混合气体3 h;Ⅰ1组和Ⅰ2组分别吸入1.2%、1.8%异氟醚3 h维持麻醉.待翻正反射消失时各组随机取3只大鼠股动脉置管监测血液动力学,于股动脉置管后5 min、吸入异氟醚1、2、3 h时抽股动脉血行血气分析;大鼠苏醒后24 h时各组随机取12只行Morris水迷宫实验测试认知功能,历时7 d,记录逃避潜伏期;分别于苏醒后24、72 h及7 d时各组随机取5只大鼠断头处死取脑,采用TUNEL法检测海马及皮层区凋亡神经元,计算神经元凋亡率.结果 三组各时点血液动力学指标及血气分析结果 差异无统计学意义(P>0.05);与C组比较,Ⅰ1组和Ⅰ2组第2、3天逃避潜伏期延长(P<0.05或0.01),第4～6天差异无统计学意义(P>0.05),苏醒后24、72 h及7 d时皮层区神经元凋亡率升高(P<0.05或0.01).结论 吸入异氟醚可导致老年大鼠认知功能一过性降低,可能与其诱发大脑皮层区神经元凋亡有关.

Effects of isoflurane on neuronal apoptosis In aged rats

Objective To investigate the effects of different concentrations of isoflurane on neuronal apoptosis in hippocampus and cerebral cortex in the aged rats. Methods Ninety female pathogen-free SD rats 22-24 months old weighing 497-593 g were randomly divided into 3 groups: group Ⅰ oxygen group inhaled air enriched with 40% O2,groupⅡ and Ⅲ were anesthetized with 1.2% and 1.8% isoflurane for 3 h respectively. Morris water maze was used to assess the cognitive function. The animals were killed at 24 and 72 h and on the 7th day after emergence from anesthesia and their brains were removed. Neuronal apoptosis in hippocampus and cerebral cortex was detected by TUNEL. Results The average escape latency was significantly longer on the 2nd and 3rd day after isoflurane anesthesia in isoflurane group than in oxygen group (P < 0.05 ). The neuronal apoptesis rate was significantly higher in the 2 isoflurane group than in oxygen group (P < 0.05 or 0.01 ). Conclusion Isoflurane anesthesia can result in transient cognitive dysfunction, and the mechanism may be involved in apoptosis in cerebral cortex in the aged rats.