异氟醚对老龄大鼠海马CA3区突触素表达的影响

目的 评价异氟醚对老龄大鼠海马CA3区突触素表达的影响.方法 雌性清洁级SD大鼠63只,月龄24月,体重400～650 g,随机分为3组(n=21):对照组(C组)、1.2%异氟醚组(E_1组)和1.8%异氟醚组(E_2组).C组吸入含40%氧气的空氧混合气体3 h;E_(1,2)组吸入3%异氟醚行麻醉诱导,待翻正反射消失后再分别吸入1.2%、1.8%异氟醚维持3 h.各组随机取12只大鼠,于麻醉结束后第1天采用Morris水迷宫系统测定大鼠认知功能(逃避潜伏期和探索时间),连续测定7 d;随机取9只大鼠于麻醉结束后第1、3和7天处死,测定海马CA3区突触素的表达水平.结果 与C组比较,E_1组和E_2组麻醉结束后第2、3天逃避潜伏期延长(P<0.05或0.01),第4～6天逃避潜伏期差异无统计学意义(P>0.05),麻醉结束后海马CA3区突触素表达持续下调(P<0.05).三组探索时间比较差异无统计学意义(P>0.05);与E_1组比较,E_2组逃避潜伏期差异无统计学意义(P>0.05),海马CA3区突触素表达下调(P<0.01).结论 异氟醚致老龄大鼠认知功能障碍与海马突触素表达无关.

Effect of isoflurane on synaptophysin expression in hippocampal CA3 area in aged rats

Objective To investigate the effect of isoflurane on the synaptophysin expression in hippocampal CA3 area in aged rats. Methods Sixty-three 24-month-old SD rots, weighing 400-650 g, were randomly divided into 3 groups (n=21 each): control group (group C), 1.2% isoflurane group (group E_1), and 1.8% isoflurane group (group E_2). The rats in group C only inhaled a gas mixture containing 40% oxygen for 3 h. The rats in group E_1 and E_2 inhaled 3% isoflurane for induction, and after righting reflex disappeared, the concentration was reduced to 1.2% and 1.8% respectively which was maintained for 3 h. Twelve rats randomly selected from each group underwent Morris water maze teat for assessment of learning and memory function (escape latency and probe time). The training test was performed 4 times a day for 7 d. Nine rats randomly selected from each group were decapitated at day 1,3, and 7 after the termination of anesthesia. The hippocampal CA3 area was isolated for determination of synaptophysin expression. Results The escape latency was significantly longer at day 2 and 3 after the termination of anesthesia in group E_1 and E_2 than in group C (P < 0.05 or 0.01), and no significant difference in escape latency was found at day 4-6 after the termination of anesthesia between group E_1 and E_2 and group C (P > 0.05). The synaptophysin expression in hippocampal CA3 area was significantly lower in group E_1 and E_2 than in group C (P < 0.05), and no significant difference in the probe time was found between the 3 groups (P > 0.05). There was no significant difference in escape latency between group E_2 and group E_1 (P > 0.05), and the synaptophysin expression in hippocampal CA3 area was significantly lower in group E_2 than in group E_1 (P < 0.01). Conclusion The cognitive dysfunction induced by isoflurane anesthesia in aged rats is not related to the synaptophysin expression in hippocampal CA3 area.