钙蛋白酶在七氟醚麻醉诱发老龄大鼠海马神经元凋亡中的作用

Role of calpain in sevoflurane anesthesia-induced apoptosis in hippocampal neurons of aged rats

目的 评价钙蛋白酶在七氟醚麻醉诱发老龄大鼠海马神经元凋亡中的作用.方法 健康雌性SD大鼠54只,18月龄,体重450～ 550 g,采用随机数字表法,将其分为3组（n=18）：对照组（C组）、七氟醚组（Sev组）和钙蛋白酶抑制剂MDL28170组（M组）.C组吸入50％O2-50％N2混合气体3 h;Sev组吸入3％七氟醚3 h;M组尾静脉注射MDL28170 10 mg/kg,30 min后吸入3％七氟醚3h,同时尾静脉输注MDL28170 3.33 mg·kg-1·h-1.每组取9只大鼠,分别于麻醉前30 min和麻醉后1～5d时采用Morris水迷宫实验评价认知功能,记录逃避潜伏期和穿越原平台次数;分别于麻醉前30 min和麻醉后1、5d水迷宫测试结束后,每组处死3只大鼠,取海马组织,采用流式细胞术测定神经元凋亡率和胞浆钙离子浓度.结果 与C组比较,Sev组和M组麻醉后1d时逃避潜伏期延长,穿越原平台次数减少,神经元凋亡率和胞浆钙离子浓度升高（P＜0.05）;与Sev组比较,M组麻醉后1d时逃避潜伏期缩短,穿越原平台次数增多,神经元凋亡率降低（P＜0.05）,胞浆钙离子浓度差异无统计学意义（P＞0.05）.结论 钙蛋白酶激活参与了七氟醚麻醉诱发老龄大鼠海马神经元凋亡.

Objective To evaluate the role of calpain in sevoflurane anesthesia-induced apoptosis in hippocampal neurons of aged rats.Methods Fifty-four healthy female Sprague-Dawley rats,aged 18 months,weighing 450-550 g,were randomly divided into 3 groups （n=12 each） using a random number table：control group （group C）,sevoflurane group （Sev group） and calpain inhibitor M DL28170 group （group M）.In group C,the rats inhaled 50％ O2-50％N2 for 3 h.In Sev group,the rats inhaled 3％ sevoflurane for 3 h.In group M,MDL28170 10 mg/kg was injected via the tail vein,30 min later 3％ sevoflurane was inhaled for 3 h,and MDL28170 was simultaneously infused at 3.33 mg · kg 1 · h-1 via the tail vein.Nine rats in each group were selected,and cognitive function was assessed by using Morris water maze test at 30 min before anesthesia and 1-5 days after anesthesia.The escape latency and frequency of crossing the original platform were recorded.After the end of Morris water maze test performed at 30 min before anesthesia and 1-5 days after anesthesia,3 rats in each group were sacrificed,and hippocampal tissues were obtained for detection of cell apoptosis （by flow cytometry） and intracellular [Ca2＋] i.Apoptotic rate was calculated.Results Compared with group C,the escape latency was significantly prolonged,and the frequency of crossing the original platform was decreased,and the apoptotic rate and intracellular [Ca2＋]i were increased at 1 day after anesthesia in Sev and M groups.Compared with group Sev,the escape latency was significantly shortened,the frequency of crossing the original platform was increased,and the apoptotic rate was decreased at 1 day after anesthesia,and no significant change was found in intracellular [Ca2＋]i in group M.Conclusion Calpain activation is involved in sevoflurane anesthesia-induced apoptosis in hippocampal neurons of aged rats.