Objective To investigate the protective effect of Linggui Zhugan Decoction on myocardial injury in diabetic rats;To explore its molecular mechanism.Methods The diabetes myocardial injury rat model was established by intraperitoneal high fat diet combined with injection of streptozotocin.Successfully modeled rats were randomly divided into model group,simvastatin group(5 mg/kg)and Linggui Zhugan Decoction low-and high-dosage group(3.75,7.5 g/kg).Normal rats were set as blank group,and each medication group was intervened with corresponding drugs.Fasting and random blood glucose were monitored using a glucometer,the left ventricular ejection fraction(LVEF)was measured,serum contents of total cholesterol(TC),triglyceride(TG),low-density lipoprotein cholesterol(LDL-C),high-density lipoprotein cholesterol(HDL-C),superoxide dismutase(SOD)and malondialdehyde(MDA)were detected by biochemical kits,the contents of cardiac troponin I(cTnI)and creatine kinase-MB(CK-MB)were detected by ELISA,the myocardial morphology and fibrosis were observed by HE and Masson staining,the positive expression of PDCD4 was detected by immunohistochemistry,the mRNA expressions of miR-21,PDCD4,PTEN and p53 were detected by RT-qPCR,and the protein expressions of PDCD4,PTEN and p53 were detected by Western blot.Results Compared with the blank group,fasting blood glucose and random blood glucose significantly increased at different time points in the model group(P<0.05,P<0.01),LVEF significantly decreased(P<0.01),the contents of serum TC,TG,LDL-C,HDL-C,MDA,cTnI,CK-MB significantly increased(P<0.05,P<0.01),and the content of SOD significantly decreased(P<0.01);the inflammatory cells infiltration and fibrosis injury in myocardial tissue were significantly aggravated(P<0.01),the expression of miR-21 in myocardial tissue significantly decreased,and the mRNA and protein expressions of PDCD4,PTEN,p53 significantly increased(P<0.05,P<0.01).Compared with the model group,fasting blood glucose significantly decreased in simvastatin group and Linggui Zhugan Decoction high-dosage group(P<0.05),LVEF significantly increased(P<0.01),the contents of serum TC,TG,LDL-C,HDL-C,MDA,cTnI and CK-MB significantly decreased(P<0.05,P<0.01),the content of SOD significantly increased(P<0.05,P<0.01);the inflammatory cells infiltration and fibrosis injury in myocardial tissue were significantly improved(P<0.01),the expression of miR-21 in myocardial tissue significantly increased,and the mRNA and protein expressions of PDCD4,PTEN,p53 significantly decreased(P<0.05,P<0.01).Conclusion Linggui Zhugan Decoction may inhibit the expressions of PDCD4,PTEN and p53 by increasing miR-21,thereby alleviating myocardial injury in diabetic rats.

Objective To investigate the protective effect of Linggui Zhugan Decoction on myocardial injury in diabetic rats;To explore its molecular mechanism.Methods The diabetes myocardial injury rat model was established by intraperitoneal high fat diet combined with injection of streptozotocin.Successfully modeled rats were randomly divided into model group,simvastatin group(5 mg/kg)and Linggui Zhugan Decoction low-and high-dosage group(3.75,7.5 g/kg).Normal rats were set as blank group,and each medication group was intervened with corresponding drugs.Fasting and random blood glucose were monitored using a glucometer,the left ventricular ejection fraction(LVEF)was measured,serum contents of total cholesterol(TC),triglyceride(TG),low-density lipoprotein cholesterol(LDL-C),high-density lipoprotein cholesterol(HDL-C),superoxide dismutase(SOD)and malondialdehyde(MDA)were detected by biochemical kits,the contents of cardiac troponin I(cTnI)and creatine kinase-MB(CK-MB)were detected by ELISA,the myocardial morphology and fibrosis were observed by HE and Masson staining,the positive expression of PDCD4 was detected by immunohistochemistry,the mRNA expressions of miR-21,PDCD4,PTEN and p53 were detected by RT-qPCR,and the protein expressions of PDCD4,PTEN and p53 were detected by Western blot.Results Compared with the blank group,fasting blood glucose and random blood glucose significantly increased at different time points in the model group(P<0.05,P<0.01),LVEF significantly decreased(P<0.01),the contents of serum TC,TG,LDL-C,HDL-C,MDA,cTnI,CK-MB significantly increased(P<0.05,P<0.01),and the content of SOD significantly decreased(P<0.01);the inflammatory cells infiltration and fibrosis injury in myocardial tissue were significantly aggravated(P<0.01),the expression of miR-21 in myocardial tissue significantly decreased,and the mRNA and protein expressions of PDCD4,PTEN,p53 significantly increased(P<0.05,P<0.01).Compared with the model group,fasting blood glucose significantly decreased in simvastatin group and Linggui Zhugan Decoction high-dosage group(P<0.05),LVEF significantly increased(P<0.01),the contents of serum TC,TG,LDL-C,HDL-C,MDA,cTnI and CK-MB significantly decreased(P<0.05,P<0.01),the content of SOD significantly increased(P<0.05,P<0.01);the inflammatory cells infiltration and fibrosis injury in myocardial tissue were significantly improved(P<0.01),the expression of miR-21 in myocardial tissue significantly increased,and the mRNA and protein expressions of PDCD4,PTEN,p53 significantly decreased(P<0.05,P<0.01).Conclusion Linggui Zhugan Decoction may inhibit the expressions of PDCD4,PTEN and p53 by increasing miR-21,thereby alleviating myocardial injury in diabetic rats.