复合应激对大鼠皮质细胞凋亡的影响及其机制

EFFECT OF MULTIPLE STRESSES ON RAT CORTICAL CELL APOPTOSIS AND ITS MECHANISM

目的探讨复合应激对大鼠皮质细胞凋亡的影响,以期为应激致脑皮质损伤的研究提供一定的实验依据。方法选择成年雄性SD大鼠30只,实验期每日采用7种应激源：即禁食/禁水、昼夜颠倒、鼠笼倾斜45度、单笼孤独饲养、限制活动、4℃冷应激、20℃强迫游泳刺激实验大鼠3~4周,以建立复合应激动物模型;以TUNEL试剂盒检测大鼠脑皮质部位原位细胞凋亡的变化,Western blot检测ERK1/2的活化表达水平。结果复合应激3周后,复合应激组大鼠体质量为（236.7±25.2）g,明显低于对照组（270.3±23.7）g,（P〈0.05）;复合应激组0.5 h和1 h时的蔗糖消耗量分别为（64.76±17.80）%和（67.33±14.35）%,明显少于对照组（82.73±20.67）%和（80.20±15.41）%（P〈0.05）;TUNEL原位凋亡检测实验发现,复合应激后大鼠皮质细胞凋亡数目明显增加（P〈0.01）;Western blot检测显示,复合应激后,p-ERK1表达增强（P〈0.05）,p-ERK2无明显改变。结论复合应激可以显著增加大鼠皮质细胞的凋亡,ERK1蛋白磷酸化水平的提高可能参与了复合应激所致的大鼠脑皮质部位凋亡的形成过程。

Objective To study the effect of multiple stresses on cell apoptosis in prefrontal cortex（PFC） of rats in vivo,so as to provide some experimental evidences for the research of PFC cortical damage induced by stress.Methods Thirty male SD rats were randomly divided into control group and stress group.Rats in stress group were stressed everyday by seven stressors including food or water deprivation,day and night reverse,cage tilted at 45 degrees,single cage alone,restraint,4 ℃cold exposure,and forced swimming for 3～4 weeks,and then the number of cell apoptosis was determined by TUNEL in situ assay kit.Western blot was performed to determine the expression and phosphorylation of extracellular signal-regulated kinase（ERK） in prefrontal cortex of the brain.Results The body weight of stressed rats（（236.7±25.2） g） was less than that of the control（（270.3±23.7）g）（P0.05）;the sucrose consumption of stressed rats at 0.5 h,and 1 h（（64.76±17.80）%,and（67.33±14.34）% respectively）were lower than those of the control（（82.73±20.67）%,（80.20±15.41）%）（P0.05）;the stresses also resulted in significantly higher number of cell apoptosis and increased p-Erk1 expression in prefrontal cortex（P0.05）.Conclusion Multiple stresses may lead to cell apoptosis of prefrontal cortex by increasing the phosphorylation of Erk1.