| Objective: OBJECTIVE: To investigate the establishment of a model of diabetic cardiomyopathy(DCM)in Bama miniature pigs by intravenous streptozotocin(STZ),to determine the optimal modeling method,and to study the metabolism of a model of diabetic cardiomyopathy in Bama miniature pigs.Characteristics and changes in myocardial histopathology provide a suitable animal model for future research in a wider range of diabetic cardiomyopathy.Methods :Experiment 1: Establishment and identification of the best modeling method for DCM in Bama miniature pigs: 12 healthy male Guangxi Bama miniature pigs aged 4-5 months and body weight 19-25 kg were selected,three times a day for common feed feeding They were randomly divided into two groups: normal control group(n=6)and DCM model group(n=6).After 12 hours of fasting in the DCM model group,STZ 150 mg/kg was injected into the single ear vein.The general condition of the two groups of small pigs was observed,and the changes in body weight and fasting blood-glucose(FPG)levels before and after modeling were recorded.Before the model was established,at the end of June and at the end of October,the anterior vena cava was used to measure alanine aminotransferase(ALT),aspartate aminotransferase(AST),and creatinine(creatinine).Cr)and blood urea nitrogen(BUN)concentration were selected fromthe normal control group and the DCM model group at 6 months after model establishment.HE staining and pancreatic β-cell immunohistochemical staining were performed on pancreas and myocardial tissue.At the end of October,all the samples were sacrificed,and the myocardial tissues of two groups of small pigs were taken for HE and MASSON staining.Experiment 2: Replicability and characteristics of DCM in Bama miniature pigs: 10 healthy male Guangxi Bama miniature pigs aged 4-5 months were randomly divided into 2 groups: normal control group(n=5),DCM model group(n=5).After the DCM model group was fasted for 12 h,the model was established according to the modeling method of Experiment 1.The basic conditions and biochemical indexes of the two groups of miniature pigs were measured and recorded.At the end of October,the two groups of small pigs were all sacrificed after anterior vena cava blood collection.The biochemical indicators were recorded and the oxidative stress of small pig serum was detected by kit.Indicators: Malondialdehyde(MDA),Orgotein Superoxide Dismutase(SOD),glutathione peroxidase(GSH-PX);Western blot analysis of NF-KB in small pig myocardial tissue Expression of p65,BcL-2,Bax,TGFβ1.After the model was established at the end of October,the two groups of small pigs were harvested by electron microscopy.Results: Experiment 1:(1)The small pigs in the DCM model group were modeled,showing typical symptoms of “three more and one less”,no death and infection.(2)Compared with the control group,the FPG level of the DCM model group increased significantly and remained at a high level(P(27)0.01).(3)At the end of June and the end of October after the miniature pig model was established,3 days after the model establishment.The weight of the normal control group continued to increase,while the weight gain of the small pigs in the DCM model group was not obvious,which was different from the DCM model group(P(27)0.01).(4)At the end of June,the levels of ALT,AST,BUN and Cr in the two groups were not statistically significant(P>0.05).At the end of October after STZ modeling,compared with the normal control group,the level of DCM model group’s AST,BUN,Cr was significantly increased(P<0.05,P<0.01).(5)At the end of June at the end of the model,HE staining results of pancreas and myocardial tissue of the two groups of small pigs showed that the islet cells were significantly reduced,the islet cell distribution disorder,atrophy,vacuolar degeneration and other pathological manifestations were observed in the DCM model group.The results of islet β-cell immunohistochemical staining showed that there were several islet cell clusters scattered in the DCM model group,and the cells were arranged disorderly.The HE staining results of myocardial tissue showed that the muscle fibers were arranged neatly and the distribution was relatively uniform.(6)HE staining results of myocardial tissue at the end of October at the end of the model showed that in the DCM model group,small pig porcine cardiomyocytes have different degrees of degeneration(such as vacuolar degeneration,water degeneration,etc,necrosis and apoptosis,and local inflammatory cell infiltration is observed.The results of MASSON staining showed that the cardiomyocytes showed edema,enlarged volume,swelling,dissolution,etc.,fibrosis was serious,and the overall structure was extremely disordered and irregular.Experiment 2:(1)4 mice in the DCM model group were modeled and 1 died;(2)At the end of October after modeling,compared with the normal control group,the FCM and ALT levels in the DCM model group were significantly higher;(3)The results of detection of serum oxidative stress in the kit indicated that compared with the normal control group,the content of MDA in the DCM model group was significantly increased,and the activities of SOD and GSH-PX were significantly decreased(P<0.01).(4)Compared with normal control Compared with the group,the expression of NFKBp65,BAX and TGFβ1 protein in myocardial tissue of DCM model group was significantly increased,and the expression of BCL-2 protein was significantly decreased(P<0.05,P<0.01).(5)Electron microscopy of myocardial tissue at the end of October after modeling showed that the myofibrils were disordered in myocardium,the number of mitochondria in myofibrils was significantly reduced,and a large number of vacuolar degeneration mitochondria were observed in myocardial tissue.Conclusions: The large-dose STZ(150mg/kg)disposable ear vein injection can successfully construct the BCM miniature pig DCM model after10 months.The model has good repeatability and stability.The DCM model group has obvious glucose metabolism disorder and oxidation.Injury,and myocardial tissue in the DCM model group showed inflammatory response,cardiomyocyte apoptosis and fibrosis. |
