低氧环境下异丙酚对新生大鼠学习记忆功能的影响

目的 探讨低氧环境下异丙酚对新生大鼠学习记忆功能的影响.方法 健康SD大鼠84只,日龄7 d,按照随机数字表法分为6组(n=14):异丙酚低氧组(PH组)、异丙酚空气组(PA组)和异丙酚纯氧组(PO组)分别腹腔注射异丙酚50 mg/kg,1次/d,连续7 d;生理盐水低氧组(CH组)、生理盐水空气组(CA组)和生理盐水纯氧组(CO组)腹腔注射生理盐水5.0 ml/kg,1次/d,连续7 d.每次注射完毕后分别放于低氧(18%O2)、空气和纯氧环境中.记录给药后SaO2和RR,待翻正反射恢复后放回鼠笼.于第7天注射完毕后24 h,各组随机取6只大鼠,取脑组织,观察海马神经元凋亡情况.其余大鼠于给药后2周进行Morris水迷宫实验,测试学习记忆功能.结果 与CO组比较,PO组RR降低,T1.2时逃逸潜伏期延长(P＜0.05);与CA组比较,PA组RR和SaO2降低,凋亡指数升高,逃逸潜伏期延长,穿越原平台区次数减少(P＜0.05);与CH组比较,PH组RR和Sa02降低,凋亡指数升高,逃逸潜伏期延长,穿越原平台区次数减少(P＜0.05);与PO组比较,PA组和PH组SaO2降低,凋亡指数升高,逃逸潜伏期延长,穿越原平台区次数减少(P＜0.05).CO组、CA组和CH组上述各指标差异无统计学意义(P＞0.05).结论 在低氧环境下,异丙酚可诱发新生大鼠海马神经元明显凋亡,降低学习记忆功能.

Effect of propofol on learning and memory function in neonatal rats under hypoxic conditions

Objective To investigate the effect of propofol on the learning and memory function in neonatal rats under hypoxic conditions. Methods Eighty-four 7-day-old SD rats were randomly divided into 6 groups (n = 14 each): propofol + 18% oxygen (propofol-hypoxia, group PH), propofol + air (group PA), propofol +100% oxygen (propofol-oxygen, group PO), 0.9% normal saline (NS) + 18% oxygen (group CH), NS + air (group CA), NS + 100% oxygen (group CO). The rats received injection of intraperitoneal propofol 50 mg/kg or NS 5.0 ml/kg once a day for 7 consecutive days and they were exposed to 18% oxygen, air or 100% oxygen at the end of each injection. SaO2 and respiratory rate (RR) were monitored and recorded after administration. The rats were returned to the cage after recovery of the righting reflex. Six rats in each group were sacrificed 24 h after the 7th injection, and the brain tissues were taken to observe the apoptosis in hippocampal neurons. Morris water maze test was used to test the learning and memory function 2 weeks after administration in the other rats. Results RR was significantly lower and the escape latency at T1.2 longer in group PO than in group CO (P ＜ 0.05). RR and SaO2 were significantly decreased, apoptotic index was increased, the escape latency was prolonged and the frequency of crossing the original platform was reduced in group PA compared with group CA, and in group PH compared with group CH (P ＜ 0.05). Compared with group PO, SaO2 was significantly decreased, apoptotic index was increased, the escape latency was prolonged and the frequency of crosing the original platform was reduced in group PA (P ＜ 0.05). Conclusion Propofol induces apoptosis in hippocampal neurons and decreases the learning and memory function in neonatal rats under hypoxic conditions.