百合知母汤对抑郁症大鼠海马组织钙调蛋白信号通路中关键分子水平的影响及其抗抑郁机制

摘要

目的：研究百合知母汤的抗抑郁作用及其对抑郁症大鼠海马组织钙调蛋白（CaM）信号通路中关键分子 CaM、钙调蛋白激酶Ⅱ（CaMKⅡ）和 cAMP 反应元件结合蛋白（CREB）表达的影响，探讨百合知母汤的抗抑郁机制。方法：50只大鼠随机分为对照组、模型组、阳性药氟西汀组和百合知母汤低、高剂量组，每组10只；除对照组外，其余各组大鼠采用慢性轻度不可预见性温和刺激结合孤养方法制备抑郁症模型，共计21 d；对照组、模型组大鼠给予生理盐水，其余各组大鼠分别灌胃给予氟西汀（1.8 mg·kg－1）和百合知母汤（1.5、3.0 g·kg－1），共计28 d。分别采用 Morris 水迷宫实验、敞箱实验和强迫游泳实验检测各组大鼠学习记忆功能、自主活动能力及5 min 内不动时间。采用尼氏染色观察大鼠海马神经元的损伤及修复状况。分别采用 Western blotting 法和 RT-PCR 法检测大鼠海马组织 CaM、CaMKⅡ蛋白和 CREB mRNA 的表达水平。结果：与模型组比较，百合知母汤组和氟西汀组大鼠在 Morris 水迷宫平台象限的总时间、总路程和穿越平台的次数增加（P ＜0.05或 P ＜0.01），第一次穿越平台的用时缩短（P ＜0.01），敞箱实验总得分增加（P ＜0.01），强迫游泳实验中5 min 内的不动时间缩短（P ＜0.05或 P ＜0.01）；与氟西汀组比较，百合知母汤高剂量组大鼠游泳实验中5 min内不动时间缩短（P ＜0.05）。尼氏染色，与模型组比较，氟西汀组及百合知母汤低、高剂量组大鼠海马神经元的损伤得到改善。Western blotting 法检测，与模型组比较，百合知母汤组大鼠海马组织中 CaM 和 CaMKⅡ蛋白表达水平升高（P ＜0.05或 P ＜0.01）；RT-PCR 法检测，与模型组比较，氟西汀组及百合知母汤组大鼠海马组织中 CREB mRNA 表达水平明显升高（P ＜0.05或 P ＜0.01）。结论：百合知母汤有抗抑郁作用，能改善抑郁症大鼠海马神经元的损伤，其作用机制与提高抑郁症大鼠海马组织 CaM 信号转导通路中的 CaM、CaMKⅡ和CREB 等关键分子表达水平有关联。%Objective:To study the antidepressant effect of Baihe Zhimu decoction (BZD)and its influence in the key factors (CaM,CaMKⅡ,CREB)of CaM signaling pathway in hippocampus of the rats with depression,and to explore the antidepressant effect of BZD. Methods:Fifty rats were divided into control group,model group, fluoxetine group,low and high doses of BDZ groups (n = 10).Expect for control group,all the rats in other groups were made depression models by means of chronic unpredictable mild stress along with isolated raising,for 21 d.Then the rats were fed with NS, fluoxetine (1.8 mg · kg-1 ), and BZD (1.5 and 3.0 g · kg-1 ), respectively;for 28 d.The learning and memory ability,autonomous activities and the fixed time in 5 min of the rats were tested by Morris water amaze,Open-field Test and Forced Swimming Test respectively. The damage and repair status of hippocampal neurons were observed by Nissl staining method;the expression levels of CaM,CaMKⅡ protein,CREB mRNA in hippocampus of the rats were detected by Western blotting and RT-PCR method. Results:Compared with model group,the total time of rats in the platform quadrant of Morris water maze in BZD groups and fluoxetine group,the total distance and the number of crossing platform were increased (P <0.05 or P <0.01),and the time of first crossing platform were shortened (P <0.01);the total scores in open field test were increased (P <0.01),the fixed time with 5 min in the forced swimming test was shortened (P <0.05 or P <0.01).Compared with fluoxetine group,the fixed time within 5 min of the rats in swimming test was shortened (P <0.05).The result of Nissl staining showed that the hippocampal neuron injury in BZD groups and fluoxetine group was improved compared with model group.The molecular test results showed that the CaM and CaMKⅡprotein expression levels in hippocampus of the rats in BZD groups and fluoxetine group were increased compared with model group (P < 0.05 or P < 0.01).Compared with model group,the CREB mRNA expression levels in fluoxetime group and BZD groups were increased (P < 0.05 or P < 0.01).Conclusion:BZD has antidepressant effect and can improve the hippocampal neuron injury of the rats with depression and its mechanism is related to increasing the expression levels of CaM,CaMKⅡ and CREB in hippocampus CAM signaling pathway of the rats.