Résumé
Objective To observe the changes and significance of the protein expression levels of nuclear factor-κB p65 (NF-κB p65), transforming long factor-β1 (TGF-β1) and apoptosis-related factors Bcl-2 and Bax in myocardial tissue of Bama miniature pig model of diabetic cardiomyopathy (DCM). Methods Ten healthy male Guangxi Bama miniature pigs, aged 4 to 5 months old, were selected and divided into control group and model group according to the random number table method, with 5 pigs in each group. After 12 hours of fasting in the two groups, the DCM model was replicated by intravenous injection of streptozotocin (STZ) 150 mg/kg; for the Bama miniature pigs in the control group, citric acid-sodium citrate buffer 150 mg/kg was injected intravenously. After 10 months of modeling, the basic conditions of the two groups of animals were observed and their fasting blood glucose (FPG) levels were detected. The protein expression levels of NF-κB p65, TGF-β1, Bcl-2 and Bax in myocardial tissue of two groups were detected by Western Blot and the pathological changes of myocardial tissue were observed under electron microscope. Results In the model group, 4 models were successfully established, and 1 died. The model pigs had symptoms such as polydipsia, polyphagia, polyuria and decreased body weight. The FPG level in the model group was significantly higher than that in the control group (mmol/L: 25.53±3.75 vs. 4.68±0.77, P < 0.01). Compared with the control group, the protein expression levels of NF-κB p65, Bax and TGF-β1 in the myocardial tissue of model group were significantly increased (NF-κB p65/GAPDH: 0.46±0.05 vs. 0.38±0.02, Bax/GAPDH: 0.46±0.01 vs. 0.35±0.01, TGF-β1/GAPDH: 0.39±0.01 vs. 0.33±0.01, all P < 0.05) and the expression level of Bcl-2 protein was significantly decreased (Bcl-2/GAPDH: 0.33±0.01 vs. 0.42±0.01, P < 0.01). Electron microscopy results showed that the myofibrils of myocardial tissue in the DCM model group were disordered, and the number of mitochondria in the gap was significantly reduced. A large number of mitochondria with vacuolar degeneration were observed. Conclusions The DCM model of Bama miniature pigs can be successfully replicated after 10 months of high-dose STZ disposable ear vein injection. The DCM model miniature pigs have obvious glucose metabolism disorder, and their myocardial tissue has inflammatory reaction, cardiomyocyte apoptosis and fibrosis.
Résumé
Objective To study the feasibility of Bama miniature pig model establishment of type 2 diabetes mellitus (T2DM) by high-fat and high-sugar diet combined with streptozotocin (STZ), and observe the changes in protein kinase B (PKB) and phosphorylation expressions in skeletal muscle, liver, and pancreatic tissues of the miniature pig model. Methods A total of 10 healthy male Bama miniature pigs were randomly divided into two groups:control group (n=5, fed normal diet) and diabetic model group (n=5, fed high-fat and high-sugar diet combined with STZ to establish T2DM Bama miniature pig model). The fasting plasma glucose (FPG) and fasting insulin (FINS) levels were measured, and insulin resistance (HOMA-IR) was calculated in two groups. The PKB and phosphorylation expressions in skeletal muscle, liver and pancreatic tissues were measured using Western blot assay. Results (1) After 10 months of high-fat and high-sugar diet, the body weight, FPG, FINS and HOMA-IR were significantly higher in model group than those of control group (P<0.01). (2) After STZ treatment, compared with control group, there was a further increased level of FPG and a significantly decreased level of FINS in model group (P<0.01). (3) Compared with control group, the PKB and phosphorylation expression levels in skeletal muscle, liver and pancreas were significantly lower in model group (P<0.05). Conclusion The high-fat and high-sugar diet combined with STZ can successfully establish the T2DM miniature pig model. The PKB and phosphorylation expression levels in skeletal muscle, liver, and pancreatic tissues are decreased in model pigs.