慢性应激对大鼠心肌超微结构与热休克蛋白70表达的影响

目的研究慢性应激对大鼠心肌细胞的损害和动员的保护因素。方法将青年雄性Wistar大鼠随机分为对照组11只和实验组12只。实验组大鼠每笼1只喂养。实验第1～21天,接受各种不同的应激。对照组大鼠群养不给任何刺激。实验第22天杀死所有大鼠,速取心左室心尖部心肌各4块,制成电镜切片用透射电镜观察,制成免疫组化切片免疫组化法检测蛋白HSP70表达,进行图像分析。结果与对照组相比,实验组体质量明显下降(239.17±32.18)粒,P<0.01],水平穿越格数减少(19.12±9.76)次,P<0.01]、直立次数减少(9.47±3.93)次,P<0.05]、修饰次数减少(3.98±2.19)次,P<0.05],粪便粒数增多(4.83±2.13)粒,P<0.01]、中央格停留时间增加(5.10±2.11)s,P<0.01]。结论慢性应激可引起大鼠体质量下降及行为学改变。慢性应激可引起心肌细胞超微结构改变,慢性应激可引起心肌HSP70表达增强。

Effects of chronic stress on ultrastructure and the expression of heat shock protein70 in myocardium of rats

Objective To study the effects chronic stress on ultrastructure and the expression of heat shock protein70 in myocardium of rats. Methods Male Wistar rats were divided into experimental group and control group randomly , 12 rats and 11 rats respectively.Experimental group were fed separately one rat in one box. from 1~21 days, accept various types of stresses. The control group were fed in two boxes, no stress from 1-21days.On 22th day killed all the rats.Four small pieces of myocardium were immediately dissected from cardiac apex of left ventricles respectively.Sections for transmission electronmicroscope and Immunohistochemistry were make respectively.Ultrastructure of myocardium were observed. Used immunohistochemistry method to measure the expression of HSP70 protein in myocardium and analyze optical density(OD) average of HSP70. Results After 21 days stress, weight(P<0.01), ambulation(P<0.01), rearing(P<0.05) and grooming(P<0.05) decreased and stopping time in center(P<0.01), defecation(P<0.01) increased in experimental group.The ultrastructural changes of the myocardium were observed in rats of chronic stress group,including stroma edema of myocardial cells,myofibril disorder,mitochondrion degeneration,intercalated disc dissociation,endothelium edema . The ultrastructure in rat control group was essentially normal.HSP70 expressed obviously in experimental group ,and the expression of HSP70 in myocardium in experimental group were higher than those in control group(P< 0.001). Conclusion Chronic stress result in weight decrease and the behavior changes of rats.Chronic stress induced significant ultrastructural changes of myocardium in rats.Chronic stress induced overexpression of and HSP70 in myocardium,and HSP70 is a protection factor as well as a marker of lesion.