异氟烷麻醉大鼠认知障碍的分子机制及其与GSK-3β/β-catenin信号通路的关系

Analysis of molecular mechanism of cognitive impairment in rats anesthetized with isoflurane based on GSK-3β/β-catenin signaling pathway

目的探讨异氟烷麻醉大鼠认知障碍的分子机制及其与源糖原合成酶激酶-3β(GSK-3β)/β-连环蛋白(β-catenin)信号通路的关系。方法40只SD大鼠分为对照组、低剂量麻醉组、中剂量麻醉组、高剂量麻醉组,每组10只。低剂量麻醉组、中剂量麻醉组、高剂量麻醉组分别吸入浓度为1.5%、2.4%、3.0%的异氟烷,对照组吸入含30%的氧气和空气混合气体。12 h后采用Morris水迷宫测试各组大鼠认知功能(潜伏期和穿越原平台次数),采用HE染色观察各组大鼠海马组织形态学改变,采用Western blot检测各组大鼠海马组织GSK-3β、β-catenin蛋白水平。结果高、中、低剂量麻醉组大鼠潜伏期和穿越原平台次数均明显高于对照组(10.76±2.38 s vs.9.64±2.13 s vs.8.60±2.07 s vs.7.55±1.96 s;8.72±0.95次vs.7.88±0.83次vs.7.05±0.71次vs.6.23±0.59次),差异均具有统计学意义(P<0.05),其中高剂量麻醉组最高,其次为中剂量麻醉组,最低为低剂量麻醉组,呈剂量依赖性(P<0.05)。HE染色显示对照组大鼠海马组织形态正常;各麻醉组大鼠海马神经元细胞出现形态学改变,细胞间隙增宽,核染色质模糊不清,胞核固缩、浓染甚至破裂。高、中、低剂量剂量麻醉组大鼠海马组织GSK-3β、β-catenin蛋白水平均明显高于对照组(1.89±0.22 vs.1.37±0.18 vs.0.88±0.13 vs.0.39±0.09;1.66±0.19 vs.1.24±0.15 vs.0.85±0.11 vs.0.51±0.06),差异具有统计学意义(P<0.05);其中高剂量麻醉组最高,其次为中剂量麻醉组,最低为低剂量麻醉组,呈剂量依赖性(P<0.05)。结论异氟烷可能通过激活GSK-3β/β-catenin信号通路使大鼠海马神经元细胞形态发生改变从而造成认知功能障碍,这可为临床术后认知功能障碍发病机制及治疗靶点的研究提供新的理论依据。

Objective To investigate the molecular mechanism of cognitive impairment in rats anesthetized with isoflurane based on glycogen synthase kinase-3β(GSK-3β)/β-catenin signaling pathway.Methods 40 SD rats were divided into four groups according to the inhalation concentration of isoflurane,control group(0%),low dose anesthesia group(1.5%),middle dose anesthesia group(2.4%)and high dose anesthesia group(3.0%)with 10 rats in each group.After 12 h,the Morris water maze was used to test the cognitive function of each group(latency and number of crossing the original platform).HE staining was used to observe the morphological changes of hippocampus in each group.The levels of GSK-3βandβ-catenin in hippocampus of each group were detected by Western blot.Results The latency and number of crossing the original platform were lowest in the control group,followed by low dose anesthesia group,middle dose anesthesia group and high dose anesthesia group,with statistic difference(10.76±2.38 s vs.9.64±2.13 s vs.8.60±2.07 s vs.7.55±1.96 s;8.72±0.95 times vs.7.88±0.83 times vs.7.05±0.71 times vs.6.23±0.59 times)(P<0.05).HE staining showed that the hippocampus was normal in the control group,while different degrees of morphological changes were observed in each anesthetized group.The protein levels of GSK-3βandβ-catenin in hippocampus were lowest in the control group,followed by low dose anesthesia group,middle dose anesthesia group and high dose anesthesia group,with statistic difference(1.89±0.22 vs.1.37±0.18 vs.0.88±0.13 vs.0.39±0.09;1.66±0.19 vs.1.24±0.15 vs.0.85±0.11 vs.0.51±0.06)(P<0.05).Conclusion Isoflurane may cause cognitive dysfunction by activating GSK-3β/β-catenin signaling pathway in rat hippocampal neurons,which may provide a new theoretical basis for the pathogenesis study and target treatments of postoperative cognitive dysfunction.