Tryptase and the mechanism of type 2 diabetic cardiomyopathy

Abstract:

Objective：To study the effect of tryptase on Wistar rats in type 2 diabetic cardiomyopathy model and to provide theoretical basis for the further treatment of diabetic cardiomyopathy. Methods：Totally 45 male Wistar rats were randomly separated into 3 groups：normal control（NC） group，type 2 diabetic cardiomyopathy（DCM） group and trypsin inhibitor groups（intervention group）. The rats of DCM and intervention group received intrapperitioneal injection of streptozotocin after high fat and high glucose breeding to form an experimental model of diabetes cardiomyopathy. The rats of intervention group received 0.025% ketotifen solution 1 mg/kg twice a day by hypodermic injection. Rats in NC and DCM groups were given injection of physiological saline. After the experiment，all the rats were sacrificed. Body，all heart，left ventricular were weighted to calculate all heart and left ventricle weight index. Myocardial tissue was observed under the light microscopy；serum tumor necrosis factor-α（TNF-α） was tested by ELISA；trypsin protein ex－pression in rats of left ventricular myocardial tissue was examined by Western blot. Results：All heart and left ventricle weight index of DCM group was significantly higher than that of NC group（P<0.05）. All heart and left ventricle weight index of intervention group was lower than that of DCM group（P<0.05）. Routine HE staining results showed that，compared with those of NC group，myocardial tissue pathological changes were more visible in DCM group：disordered arrangement of cardiac muscle fiber fracture，myocyte hypertrophy，apoptosis，uncleared cell nucleus edge. Myocardial cell volume was narrowed in DCM group than in intervention group；in intervention group，myocardial cell arranged regularly with rare fracture and similar nucleus size. Serum TNF-α was significantly higher in DCM group than in NC group（P<0.05）. TNF-α was lower in in－tervention group than in DCM group. Tryptase relative grey value was higher in DCM group than in NC group（P<0.05）. Tryptase relative grey value was lower in intervention group than in DCM group（P<0.05）. Conclusion：The type 2 diabetic rats myocardial tissue has high expression of tryptase. After injection of trypsin inhibitor intervention，myocardial pathology and the expression of tryptase in diabetic cardiomyopathy rat model decreased. The increase of tryptase expression maybe participate in the occurrence of diabetic cardiomyopathy.