Study On The Relationship Between Adiponectin, Adiponectin Receptor1and Diabetic Cardiomyopathy

Objective To establish the animal model, and observe the expression of adiponectin(APN), adiponectin receptor-1(AdipoR-1) in Type2diabetic rats, and the changes ofmyocardium structure. Study of adiponectin and its receptor1in type2diabeticcardiomyopathy rats in the model and the correlation with insulin resistance,To studythe relationship between APN, AdipoR-1and diabetic cardiomyopathy.Methods Sixty Sprague-Dawley(SD) male rats were randomly assigned to modelgroup(n=40) and normal group(n=20).Model group were given food in high fat andsugar, however,normal group received regular diet.After four weeks, rats which inmodel group was induced by intraperitoneal injection of streptozotocin (STZ,30mg/Kg),meanwhile, normal group rats serving as controls were injected the same volume ofsodium citrate. We recorded the changes of body weight every week, when eight weeks,did oral glucose tolerance test(OGTT).After fasting12h, cut the tail blood and rapidblood glucose meters measure fasting blood glucose(FBG), intragastric administrationwith50%glucose injection2g/Kg body weight, after2h cut the tail blood again andmeasure2h postprandial blood glucose(2hPG).Building the type2diabetics groupwas FBG≥7.1mmol/L,2hPG11≥11.1mmol/L and continued for more than aweek.Control group, blood glucose to normal, and continue to give regular feed.thirty-two rats in2type diabetics (T2DM)group were to continue to give high-sugarhigh-fat feeding.After fourteen weeks,1day before the end of the experiment,afterfasting12h,the cardiac function was detected，heart weight(HW) and body weight(BW)were measured to calculate heart weight index (heart weight index=heart weight g/body weight kg), measured blood fat series. Plasma and myocardial adiponectin levels wereassayed by double-antibody sandwich enzyme-linked immunosorbent assay (ABC-ELISA). Computing the serum insulin and the steady state model of indexes of insulinresistance (HOMA-IR), evaluate the degree of insulin resistance (IR).mRNA expressionof adipoR1was assayed by reverse transcription polymerase chain reactions (RT-PCR),the myocardial protein expression of AdipoR1was detected by immunohistochemicalstaining.HE staining were used to detect the pathology changes of cardiac tissue. Allstatistics were analyzed via the SPSS13.0.Results1The changes of clinical characteristics and biochemical indices between eachgroup:The body weight of normal control group increased significantly but T2DMgroup not.Compared the T2DM group with the control group, the ratio of heart to bodyweight, blood glucose levels,fat levels,the serum insulin and the HOMA-IR werehigher(P<0.05).The maximum descent-speed of pressure in isovolumic relaxationperiod in the left ventricle (-dp/dtmax)was also significantly decrease in T2DMgroup(P<0.05).And the maximum ascendent-speed of pressure in isovolumiccontraction period in the left ventricle (-dp/dtmax) in the two groups no significantdifference.2Serum,myocardium adiponectin levels and expressions of AdipoR1inmyocardium: T2DM group and the control group comparison, serum adiponectin levelreducted(P<0.05), and the protein, mRN of adiponectin receptor-1were lowerlevels(P<0.05).3The changes of myocardial histology in HE staining:Compared withnormal control group,the T2DM group myocardial cells disarrangement, nucleus size ofthe irregular, and seen in muscle fibers fracture, disarrangement. However, the normalcontrol group myocardial cells arranged in neat rows, the nucleus size of the uniform,uniform cytoplasmic staining.4T2DM group rats serum adiponectin and fasting bloodglucose, cholesterol (TC), triglyceride (TG), serum insulin, the steady-state model ofinsulin resistance index showed a negative correlation.The protein of adiponectin receptor-1was correlated positively with the adiponectin.Conclusions1T2DM group of rats appeared highly index increased, the damage ofmyocardial structure pathological characteristics of diabetic cardiomyopathy.2Diabeticcardiomyopathy and rat myocardium and serum adiponectin levels drop; Blood lipids,blood glucose metabolic disorder and insulin resistance is closely associated withadiponectin levels drop.3Diabetic cardiomyopathy in rats myocardial adiponectinreceptor1mrna and protein expression decreased and reduced insulin sensitivity.