糖尿病对心肌时钟基因Bmal1/Per2昼夜表达影响的研究

Effects of Diabetes Mellitus on Circadian Expression of Myocardial Clock Gene Bmal1/Per2

目的探索糖尿病对心肌时钟基因Bmal1/Per2昼夜表达的影响。方法无特定病原体级健康成年雄性SD大鼠44只,依据随机数字法分为非糖尿病组和糖尿病组,其中非糖尿病组采用随机数字法分为授时时间(ZT) 23亚组11只、ZT11亚组11只,糖尿病组分为ZT23亚组11只、ZT11亚组11只。糖尿病组大鼠腹腔注射1%链脲佐菌素60 mg/kg制备大鼠糖尿病模型,待糖尿病模型成功后喂养4周;同时建立昼夜节律模型,给予大鼠12 h光照/12 h黑暗周期环境。苏木素-伊红(HE)染色观察时心肌组织形态学变化;免疫组织化学实验检测ZT23时心肌病理组织学改变及时钟蛋白Bmal1和Per2在心肌的表达情况; Western bloting法检测Bmal1和Per2在蛋白水平上的表达情况。结果与非糖尿病ZT23亚组相比,糖尿病ZT23亚组Per2表达增高,Bmal1表达下降(P <0. 05);与非糖尿病ZT11亚组相比,糖尿病ZT11亚组Per2、Bmal1表达降低(P <0. 05);与非糖尿病ZT23亚组相比,非糖尿病ZT11亚组Per2表达增高,Bmal1表达降低(P <0. 05);而与糖尿病ZT23亚组相比,糖尿病ZT11亚组Per2、Bmal1表达均降低(P <0. 05)。HE染色分析心肌组织结构发现,与非糖尿病组相比,糖尿病组心肌结构排列紊乱;免疫组织化学结果提示,糖尿病ZT23亚组心肌Bmal1、Per2呈阳性表达。结论糖尿病对心肌时钟基因Bmal1/Per2的昼夜表达产生影响,其可能是糖尿病心肌损伤的原因。

Objective To explore the effect of diabetes mellitus(DM)on the circadian expression of Bmam1/Per2.Methods A total of 44 specific pathogen free healthy male SD rats were divided into non-DM(NDM)and DM groups by random number method sampling.The NDM group was further divided into a ZT23 subgroup and a ZT11 subgroup of 11 rats respectively;and the DM group was further divided into a ZT23 subgroup and a ZT11 subgroup of 11 rats respectively.A diabetic model of rat was prepared by intraperitoneal injection of 1%of streptozotocin 60 mg/kg.After diabetes model was successfully established,the rats were fed four weeks.At the same time,a circadian rhythm model was established and the rats were given 12 hours light and 12 hours darkness(L/D)cycling environment.Morphological changes of myocardium were observed with hematoxylin-eosin(HE)staining;myocardial histopathological changes and expression of clock proteins Bmal1 and Per2 in myocardium during ZT23 were detected by immunohistochemistry;Bmal1 and Per2 were detected by Western blotting assay.Results Compared with the ZT23 NDM subgroup,the expression of Per2 in the ZT23 DM subgroup was higher,and the expression of Bmal1 was decreased(P<0.05);compared with the ZT11 NDM subgroup,Per2 and Bmal1 expression of ZT11 DM subgroup decreased(P<0.05);compared with ZT23 NDM subgroup,Per2 expression of ZT11 NDM subgroup increased,Bmal1 expression decreased(P<0.05);compared with the ZT23 DM subgroup,the expre-ssion of Per2 and Bmal1 in the ZT11 DM subgroup decreased(P<0.05).HE staining analysis of myocardial tissue structure found that compared with the NDM group,the myocardial structure of the ZT23 DM group was disordered;immunohistochemistry indicated that in the ZT23 DM subgroup Per2 and Bmal1 were positively expressed.Conclusion Diabetes mellitus affects the circadian expression of the cardiac clock gene Bmal1/Per2,which may be the cause of diabetic myocardial injury.