慢性应激抑郁大鼠脑组织形态学和行为的变化

Changes of Cerebral Morphology and Behavior in Rats with Chronic Unpredictable Mild Stress

[目的]观察慢性不可预知的温和应激抑郁模型大鼠出现抑郁状态过程中的行为学改变以及大脑组织形态学变化,探讨大脑组织形态学变化在抑郁发生、发展过程中的作用及其意义。[方法]15只Wistar雄性成年大鼠连续8周采用单笼饲养和慢性不可预知的温和应激建立抑郁模型(模型组);另15只不予任何刺激(对照组)。观察2组体重及大脑系数变化、行为学表现、液体消耗情况、血浆皮质酮水平以及大脑组织形态学结构的变化。[结果]造模过程中,与对照组相比,模型组体重增长减慢。造模结束,大脑系数降低(P<0.01);水平、垂直运动得分及清洁动作次数、糖水消耗量、1%蔗糖偏爱百分比均降低(P<0.05或P<0.01);而纯水消耗量增加(P<0.01)。血浆皮质酮水平在应激2周达高峰,高于对照组(P<0.01);应激第3周有下降的趋势。模型组大脑海马超微结构异常。[结论]慢性不可预知的温和应激可诱发大鼠较长时间、伴有行为及活动习性变化的抑郁形成,并可引起大脑组织形态学改变,这可能是抑郁发生、发展过程中的重要机制之一。

[Objective] To observe the changes of behavior and the brain structrue in rats with chronic unpredictable mild stress and to explore its role in the process.[Methods] Fifteen Wistar rats were set as the depression model group,to them the chronic unpredictable mild stress was used to support.Another 15 rats without any stimulation were set as the control group.The performance,body weight,the coefficient of brain,the consumption of liquid,plasma cortisone levels,and the changs of the brain structure in both groups were observed.[Results] During eight weeks,in the depression model group,the increase of body weight reduced,and the coefficient of brain decreased（P 〈0.01）.Scores of horizontal and vertical movements,consumption of sucrose solutions and the frequency of cleaning action were significantly reduced（P 〈0.05 or P 〈0.01）,whereas pure water consumption increased as compared with the control group（P〈 0.01）.Plasma corticosterone levels reached the peak at the second week（P 〈0.01）,but showed a declining trend at the third week.The ultrastructure changes in the hippocampus were observed by electronmicroscope.[Conclusion] The repeated chronic unpredictable mild stress stimulation can induce long-time changes in acts and activities in rats and damage their hippocampus structure.It may be one of the mechanisms in depression development.