| Diabetic cardiomyopathy(DCM)occurs in patients with diabetes which is independent of the primary myocardial damage of coronary artery disease.In the early age of DCM,there are metabolic disorders at the cellular level,with no clinical symptoms in patients.Nevertheless,with the progress of disease,left ventricular diastolic dysfunction may occur,followed by systolic dysfunction,which can seriously cause congestive heart failure or sudden death.Since its unclear mechanism,there are no precise guidelines for clinical treatment.Traditional Chinese medicine refers to diabetes as "thirst quenching ".The main pathogenesis of thirst is yin deficiency and heat,prolonged illness,and excessive yin injury can be transformed into qi and yin deficiency.Shengmai powder is composed of "Ginseng,Ophiopogon,Schisandra".Ginseng replenishes qi,Maimendong nourishes yin and relieves heat,Schisandra astringents Qi.The function of Shengmai powder is "reinforcing qi and replenishing pulse,nourishing yin and promoting health".Doctors have used them to treat disease with "palpitations,shortness of breath,and slight pulse perspiration." From the perspective of traditional Chinese medicine,DCM belongs to the category of "thirst quenching",with deficiency of Qi and Yin,and the positions of the DCM conclude heart,lung,and kidney.Shengmai powder "replenishes Qi and nourish yin" can also cure heart palpitations.A large number of previous studies show that Shengmai powder can be used for the treatment of diabetes which is interrelated with heart disease.In this experiment,the DCM model was established to explore the effect of Shengmai powder on the heart contractile function and its internal mechanism.Objective:To investigate the effects of Shengmai powder on cardiac contractile function and explore the internal mechanism by establishing a high-fat diet/streptozotocin DCM rat model,and observing the effects of Shengmai Powder on blood glucose and lipids,cardiac function,myocardial tissue morphology,and calcium transport-related proteins.Methods:After one week of adaptive breeding of 60 SD rats,10 randomly selected as control group,and the remaining 50 were fed with high-fat feed for 4 weeks,and then injected into streptozotocin(45mg/kg)to induce the diabetic model.The diabetic rats were randomly divided into Model group,Trimetazidine(TMZ)group and Shengmai powder group,besides of Control group.The daily dose of the trimetazidine group was 7 mg·kg-1,and the daily administration of the Shengmai powder group was 1050 mg·kg-1.By detecting changes in body weight,blood glucose,glucose tolerance(OGTT),water intake,water intake,triglyceride(TG),low density lipoprotein(LDL),high density lipoprotein(HDL),and cholesterol(CHO)in each group,To observe the effect of Shengmai San on the metabolic process of diabetic rats;By measuring the left ventricular ejection fraction(EF),short axis shortening rate(FS)at 4th,8th and 12th weeks after administration,and detecting the maximum change rate of left ventricular pressure(LVdp/dt Max,LVdp/dt Min),left ventricular end diastolic pressure(LVEDP),left ventricular and carotid systolic pressure(SYS),carotid diastolic blood pressure(DP),maximum rate of change in carotid pressure(Adp/dt Max,Adp/dt Min)and other hemodynamic related indicators to observe the effect of Shengmai powder on cardiac function in diabetic rats;Observe the effect of Shengmai powder on the cross-sectional area of myocardial cells by detecting HE stained sections and cardiac weight index of each group of rats;By detecting the expressions of PPARa,CaMKII,PLB,NCX1,RyR,CACNA1C,SERCA2a and the phosphorylation of PLB in myocardial tissue,the effects of Shengmai powder on myocardial calcium transporters were observed.Result:1)Effect of Shengmai powder on cardiac function in diabetic rats:1.The blood glucose,glucose tolerance(OGTT),triglyceride(TG),low density lipoprotein(LDL),high density lipoprotein(HDL),and cholesterol(CHO)of the diabetic rats in the model group were significantly increased(P<0.01,P<0.05).),Indicating successful modeling,diabetes has an effect on glucose and lipid metabolism in rats.Shengmai powder and trimetazidine administration failed to reduce the above indicators,indicating that Shengmai powder may not protect the heart function of diabetic rats by improving glucose and lipid metabolism in diabetic rats.2.The myocardial cross-sectional area of the diabetic rats in the model group increased(P<0.01)and the HMI increased(P<0.01),indicating that myocardial hypertrophy occurred in diabetic rats.The intervention of Shengmai San and trimetazidine can reduce the cross-sectional area and HMI of the cardiac muscle.Improve myocardial hypertrophy.3.In the model group,LVEDP increased(P<0.05),dp/dtmax decreased(P<0.01),SYS decreased(P<0.01),and EF and FS decreased(P<0.01,P<0.05).This indicates that the heart function of diabetic rats is decreased.In the Shengmaisan group and trimetazidine group,LVEDP decreased(P<0.05),and dp/dtmax,EF,and FS increased(P<0.01,P<0.05).This shows that Shengmai San can protect the heart function of diabetic rats.2)Effect of Shenglai powder on myocardial Ca2+ transport mechanism in diabetic rats:PLB protein phosphorylation,SERCA2a,NCX1,PPAR-a decreased in model group diabetic rats(P<0.05,P<0.05,P<0.05,P<0.01);PLB,CaMKII expression increased(P<0.05,P<0.05)This indicates that the expression of calcium ion transport-related proteins in cardiac muscle cells of diabetic rats is abnormal.The Shengmaisan group and trimetazidine group reduced PLB and CaMKⅡ(P<0.05,P<0.05);p-PLB,SERCA2a,NCX1,and PPAR-α expression increased(P<0.05,P<0.05,P<0.05,P<0.01).This indicates that Shengmai Powder may protect the impaired heart function of diabetic rats by regulating the calcium transporter protein in myocardial cells.Conclusion:Shengmai powder has a preventive and therapeutic effect on myocardial hypertrophy caused by DCM.And Shengmai powder can protect the cardiac contractile function of DCM rats by inhibiting PLB overexpression,increasing PLB phosphorylation,SERCA2a,NCX1,PPARa expression. |
