瑞芬太尼和丙泊酚对老年大鼠学习记忆的影响

目的:探讨瑞芬太尼和丙泊酚对老年大鼠学习记忆及其海马胆碱乙酰转移酶(ChAT)表达的影响。方法:雄性18月龄SD大鼠50只,随机分成5组(n=10):对照1周组(N1组),瑞芬太尼1周组(R1组),丙泊酚1周组(P1组),对照3周组(N3组),丙泊酚3周组(P3组)。R1组尾静脉注射瑞芬太尼60μg/kg,随后静脉泵注15μg/(kg.min),维持1h。P1、P3组腹腔注射60 mg/kg丙泊酚,待出现翻正反射时追加1/2首剂量,共追加2次。N1、N3组腹腔注射等量生理盐水。N1、P1、R1组于处理后第1周行Morris水迷宫实验,N3、P3组处理后第3周行水迷宫实验,每天4次,连续4 d。测试结束后灌注固定取脑,行海马组织切片的HE染色和免疫组化染色,观察海马结构及测定海马ChAT的表达。结果:①水迷宫结果:潜伏期测试各组同一时间点与对照组比较,仅在第1周的第2 d和第3 d,P1组较N1组差异有统计学意义(P<0.01或P<0.05);探索试验中通过原平台次数各组与对照组比较在第1周和第3周均无统计学意义(P>0.05)。②海马HE染色:光镜下各组大鼠海马结构未见明显异常。③海马免疫组化染色:海马CA1区ChAT阳性表达细胞数各组与对照组比较均无统计学意义。结论:麻醉剂量的丙泊酚可致老年大鼠短期学习记忆障碍,瑞芬太尼无此作用。丙泊酚和瑞芬太尼麻醉后4 d或3周对大鼠海马ChAT的表达无影响。

Effects of remifentanil and propofol on spatial learning and memory in aged rats

Objective:To investigate the effects of remifentanil and propofol on spatial learning and memory and the expression of choline acetyltransferase(ChAT) in the hippocampus of aged rats.Methods:Fifty male SD rats aged 18 months were randomly divided into 5 groups(n=10): control 1-week group(group N1),propofol 1-week group (group P1),remifentanil 1-week group(group R1),control 3-week group(group N3) and propofol 3-week group(group P3).The rats in group R1 received intravenous remifentanil 60 μg/kg,followed by remifentanil 15 μg /(kg·min) for 1 h.The rats in group P1 and P3 received intraperitoneal propofol 60 mg/kg and supplemental propofol 30 mg/kg when the rats appeared to righting reflex for 2 times,whereas the rats in control group were given equal volume normal saline in the way described above.The rats were tested with Morris water maze 4 times a day for 4 consecutive days in the 1st week or 3rd week after drug administration.The rats were infused 4% paraformaldehyde after tests and then the brain was removed for determination of hippocampal structure and ChAT expression using HE and immuno-histochemical staining.Results:① Morris water maze test showed that only the latency of group P1 was significantly longer than group N1 compared with anaesthetized and control groups(P<0.01 or P<0.05).There was no significant difference in the number of across the original platform between anaesthetized group and control group in the spatial probe test.②HE staining exposed no histological lesions of hippocampus in all groups.③Immunohistochemical staining suggested that there was no significant differences of ChAT expression in CA1 region of hippocampus between anesthetized groups and control groups.Conclusion:The data indicate anesthesia-dose propofol can lead to temporary spatial learning and memory impairment in aged rats but remifentanil infusion does not produce such effect.Remifentanil and propofol have no effects on ChAT expression in hippocampus of aged rats 4 days and 3 weeks after anesthesia.