水飞蓟宾对糖尿病小鼠心肌损伤的治疗作用及机制探讨

Protective effects of silibinin against myocardial injury in rats with diabetes mellitus and its underlying mechanism

目的观察水飞蓟宾(SIL)对糖尿病心肌损伤的治疗作用,并初步探讨其机制。方法将40只雄性C57BL/6小鼠随机均分为正常对照组、药物对照组、模型组和实验组,每组10只。模型组和实验组采用链脲佐菌素诱导联合高糖脂饮食法制备糖尿病模型。实验组、药物对照组给予SIL灌胃,正常对照组、模型组给予等体积生理盐水灌胃,干预12周后处死小鼠。测算心功能指标早期充盈峰值速度与晚期充盈速度之比(E/A)、左心室收缩末期内径(LVESD)、左心室舒张末期内径(LVEDD)、左心室射血分数(LVEF)和左心室缩短分数百分比(LVFS);观察心肌纤维化程度并计算纤维化比例,检测心肌组织中的纤维化指标TGF-β1、CollagenⅠ、CollagenⅢmRNA;检测心肌组织中氧化应激指标活性氧(ROS)、丙二醛(MDA)、超氧化物歧化酶(SOD);检测IL-6、IL-1β、TNF-αmRNA及NF-κB蛋白;比较各组心肌细胞凋亡率和凋亡相关蛋白cleaved Caspase-3表达水平。结果与正常对照组相比,模型组E/A、LVEF、LVFS降低,LVESD、LVEDD升高,心肌组织纤维化比例增高,TGF-β1、CollagenⅠ、CollagenⅢmRNA表达上调,ROS、MDA水平增高而SOD活性降低,IL-1β、IL-6、TNF-αmRNA及NF-κB蛋白表达上调,心肌细胞凋亡率和cleaved Caspase-3表达增高(P均<0.01)。与模型组相比,实验组E/A、LVEF、LVFS升高,LVESD、LVEDD减小,心肌组织纤维化比例降低,TGF-β1、CollagenⅠ、CollagenⅢmRNA表达降低,ROS、MDA水平降低而SOD活性升高,IL-1β、IL-6、TNF-αmRNA及NF-κB蛋白表达降低,心肌细胞凋亡率和cleaved Caspase-3表达减少(P均<0.01)。结论SIL可改善糖尿病心肌损伤小鼠心功能,作用机制与减轻心肌组织纤维化、抑制心肌组织氧化应激损伤和炎症反应、抑制心肌细胞凋亡有关。

Objective To observe the effect of silibinin(SIL)on myocardial injury in diabetes mellitus(DM)and to preliminarily investigate its protective mechanism.Methods Forty male C57BL/6 mice were randomly divided into four groups:Control group,SIL group,DM group and DM+SIL group,with 10 in each.Mice in the DM and DM+SIL groups were intraperitoneally injected with streptozotocin(STZ)combined with high glucose and fat diet to establish the DM models.The mice in the DM+SIL group and SIL group were treated with SIL by gavage,while the Control group and DM group with the same volune of normal saline;after 12 weeks,the mice were put to death.The ratio of early peak filling velocity to late filling velocity(E/A),left ventricular end-systolic diameter(LVESD),left ventricular end-diastolic diameter(LVEDD),left ventricular ejection fraction(LVEF)and left ventricular shortening fraction(LVFS)were measured.The degree of myocardial fibrosis was observed and the proportion of fibrosis was calculated,and the mRNA expression levels of transforming growth factor-β1(TGF-β1),Collagen I,and Collagen III were detected in the myocardial tissues.Reactive oxygen species(ROS),malondialdehyde(MDA),and superoxide dismutase(SOD)were determined in the myocardial tissues.The mRNA expression levels of interleukin-6(IL-6),interleukin-1β(IL-1β),tumor necrosis factor-α(TNF-α)and the protein expression of nuclear fator-κB(NF-κB)were analyzed.Myocardial apoptosis rate and apoptosis-related protein cleaved Caspase-3 expression level were compared in all groups.Results Compared with the Control group,E/A,LVEF and LVFS values in the DM group decreased,while LVESD and LVEDD values increased,the proportion of fibrosis increased,and the expression levels of TGF-β1,Collagen I,and Collagen III mRNA in the myocardial tissueswere up-regulated,and ROS and MDA levels increased,SOD activity decreased,IL-1β,IL-6,TNF-αmRNA and NF-κB protein expression levels were up-regulated,and cardiomyocyte apoptosis rate and cleaved Caspase-3 expression increased in the DM group(all P<0.01).Compared with the DM group,E/A,LVEF and LVFS values increased,LVESD and LVEDD values decreased,the proportion of fibrosis decreased,the expression levels of TGF-β1,Collagen I,and Collagen III mRNA were down-regulatedin the myocardial tissues,the activity of SOD increased,while the levels of ROS and MDA decreased,the expression of IL-1β,IL-6,TNF-αmRNA and NF-κB protein decreased,and the apoptosis rate of cardiomyocytes and the expression of cleaved Caspase-3 decreased in the DM+SIL group(all P<0.01).Conclusion SIL can improve cardiac function in mice with diabetic cardiomyopathy,and the protective mechanism is related to its effects of alleviating myocardial fibrosis,suppressing oxidative stress and inflammation,and inhibiting apoptosis of cardiomyocytes.