格列齐特对糖尿病大鼠心肌的保护作用及其机制

Protective effects of gliclazide on myocardium of diabetic rats and its mechanism

目的:观察格列齐特对糖尿病大鼠心肌保护作用及其可能的机制。方法:将60只健康SD大鼠随机分为正常组(NC,n=10),造模组(n=50)给予高糖高脂饲料4周后,腹腔注射STZ(45 mg/kg)建立糖尿病大鼠模型,随机抽取以FBG≥16.7 mmol/L作为糖尿病模型建立成功。将造模成功的38只糖尿病大鼠随机分为模型组(MC,n=9)、格列齐特组(Glic,80 mg/kg,n=10)、格列本脲组(Glib,2.5 mg/kg,n=10)、法舒地尔组(Fas,10 mg/kg,n=9);NC组和MC组灌胃等容积蒸馏水,Glic组和Glib组灌胃给药,Fas组采用腹腔注射。各组大鼠每天给药一次,每周记录体质量及空腹血糖(FBG),持续8周。实验结束时取血并测定心脏质量,计算心脏质量指数(HWI);测定各组糖化血红蛋白(HbA1c)、总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白(HDL-C)、低密度脂蛋白(LDL-C)含量以及血清丙二醛(MDA)水平和超氧化物歧化酶(SOD)活性;通过HE和Masson染色,观察心肌病理变化和组织胶原纤维水平;TUNEL染色观察并计算心肌细胞凋亡率;Western blot法检测心肌组织中RhoA、ROCK1、eNOS、Bcl-2和Bax蛋白表达。结果:与NC组比较,MC组FBG、HWI、HbA1c、TC、TG、LDL-C、MDA水平,心肌组织胶原沉积和心肌细胞凋亡率以及心肌组织中RhoA、ROCK1、Bax蛋白明显升高,SOD活性及HDL-C、eNOS、Bcl-2和体重显著降低(P<0.01);与MC组相比,Glic组FBG、HWI、HbA1c、TC、TG、LDL-C和MDA等指标明显下降,心肌组织胶原沉积及心肌细胞凋亡减轻,心肌组织RhoA、ROCK1、Bax蛋白表达下调(P<0.01或P<0.05),大鼠体重和血清中SOD活性,HDL-C升高,eNOS、Bcl-2蛋白水平升高(P<0.01或P<0.05)。与Glic组相比,Glib组与Fas组体重、血脂、FBG、HWI、MDA以及心肌纤维化和心肌细胞凋亡水平升高,SOD和Bcl-2降低,Glib组心肌组织RhoA、ROCK1、Bax蛋白表达上调(P<0.01或P<0.05)。结论:格列齐特可改善糖尿病大鼠心肌损伤并减轻心肌细胞凋亡水平,其机制可能与降低血糖,改善氧化应激状态,调控RhoA/ROCK1/eNOS信号通路有关。

Objective:To investigate the protective effects of gliclazide on myocardium of diabetic rats and its possible mechanisms.Methods:Sixty healthy SD rats were randomly divided into two groups:normal group(NC,n=10)and model group(n=50).Rats in model group were fed with high glucose and high fat diet for 4 weeks and then intraperitoneally injected with STZ(45 mg/kg)to establish a diabetic model and randomly selected FBG≥16.7 mmol/L as a successful diabetes model.Thirty-eight diabetic rats were randomly divided into model group(MC,n=9),gliclazide group(Glic,80 mg/kg,n=10),glibenclamide group(Glib,2.5 mg/kg,n=10)and fasudil group(Fas,10 mg/kg,n=9).NC group and MC group were given equal volume distilled water by gavage,Glic group and Glib group were treated with gliclazide or glibenclamide by gavage,and the Fas group was treated with fasudil by intraperitoneal injection.Rats in each group were given once a day and recorded body mass and fasting blood glucose(FBG)weekly for 8 weeks.At the end of the experiment,the heart weight was measured,and the heart weight index(HWI)was calculated;the contents of glycosylated hemoglobin(HbA1c),total cholesterol(TC),triglyceride(TG),high density lipoprotein(HDL-C),low density lipoprotein(LDL-C),the level of serum malondialdehyde MDA)and the activity of superoxide dismutase(SOD)were measured;the pathological changes of myocardial tissue were observed by HE and Masson staining.The expressions of RhoA,ROCK1,eNOS,Bcl-2 and Bax protein were detected by Western blot.Results:Compared with NC group,in MC group,the levels of FBG,HWI,HbA1c,TC,TG,LDL-C,MDA,myocardial collagen deposition and cardiomyocyte apoptosis rate and RhoA,ROCK1,Bax protein in myocardial tissue were increased significantly,while the SOD activity,the levels of HDL-C,eNOS,Bcl-2 and body weight were decreased significantly(P<0.01).Compared with MC group,Glic treatment decreased the levels of FBG,HWI,HbA1c,LDL-C,TG,TC and MDA,increased the levels of SOD activity and HDL-C(P<0.01 or P<0.05);decreased myocardial collagen deposition,inhibited cardiomyocyte apoptosis(P<0.01);decreased the expression levels of RhoA,ROCK1 and Bax protein;increased the levels of eNOS and Bcl-2 protein(P<0.01 or P<0.05).Compared with Glic group,in Glib group,the levels of blood lipids,BM,FBG,HWI,MDA,myocardial fibrosis and cardiomyocyte apoptosis rate were increased,the levels of SOD and Bcl-2 were decreased,and the expressions of RhoA,ROCK1 and Bax in myocardial tissue were upregulated(P<0.01 or P<0.05).Conclusion:Gliclazide significantly alleviates myocardial injury and reduces myocardial apoptosis in diabetic rats,and its mechanism may be related to lowering blood glucose,improving oxidative stress and regulating RhoA/ROCK1/eNOS signaling pathway.