| Objective:Diabetic cardiomyopathy is one of the significant causes of death in patients with type 2 diabetes. However, the treatments of those are limited,because the pathogenesis of diabetic cardiomyopathy are not completely clear yet. The basic pathology of diabetic cardiomyopathy considered abnormal myocardial cell metabolism, abnormal myocardial cell apoptosis, myocardial tissue fibrosis and lesion of cardiac autonomic nerve at present,however, inflammation and oxidative stress induced by high-fat and high-glucose which play a key role in it. Mast cell is a kind of inflammatory cells, mast cells after activation can release a large amounts of promote inflammation mediums, such as histamine, tryptase, chymotrypsin, proteoglycan, leukotriene and cytokines,which involved in the occurrence and development of diseases.To explore the role of mast cell membrane stabilizer intervention in the diabetic cardiomyopathy and provide theoretical basis to treat them,we establish the model of Wistar rat with type 2 diabetic cardiomyopathy, compared with the levels of mast cells and tryptase in normal rats,type 2 diabetic rats and Ketotifen intervention rats.Methods:1.Research object grouping:55 male Wistar rats were randomly divided into 3 groups as the normal control group (NC group), the type 2 diabetes group (DM group) and the Ketotifen intervention group (Ket group). The NC group was treated with normal chow diet. The DM group was treated with high-fat and high-glucose diet and induced by a single intraperitoneal injection of streptozotocin (STZ) to establish the model of diabetic cardiomyopathy rats. Ket group was treated with Ketotifen intervention after the model of diabetic cardiomyopathy rats were successfully established.2.After the experiment, all the rats were sacrificed and weighed followed by blood sampling,then measurement of blood glucose and lipid.3.Left ventricular was cut off and weighed with the calculation of the whole cardiac index and left ventricular mass index.4.Observation and analysis of myocardial tissues under optical microscope and electron microscope in each group.5.The modified toluidine blue staining was adopted to compare the number and distribution of mast cells in each group.6.Enzyme-linked immune-sorbent assay (ELISA) was performed to test the expression of TNF-a and ROS of the rats in each group.7. Westernblot was used to determine the expression quantity of tryptase in each group.8.Statistical analysis was performed with SPASS 17.0 software. Results: l.The body weight was decreased in DM group compared with NC group(p<0.05), but was not changed in Ket group compared with DM group(p>0.05); the blood glucose was increased in DM group compared with NC group(p<0.05),but was not changed in Ket group compared with DM group(p>0.05); the blood lipid was increased in DM group compared with NC group(p<0.05),but was not changed in Ket group compared with DM group(p>0.05).2.The cardiac index was increased in DM group compared with NC group(p<0.05),and was decreased in Ket group compared with DM group(p<0.05); the left ventricular mass index was increased in DM group compared with NC group(p<0.05),and was decreased in Ket group compared with DM group(p<0.05).3. Regular HE staining demonstrated that compared with the NC group, the DM group was noted with pathological changes of myocardial tissue, showing obvious disordered arrangement and breakage of cardiac muscle fibers, hypertrophy and apoptosis of myocardial cell, and unclear cell nucleus border. The size of myocardial cell in the Ket group was decreased in different degrees compared with that of the DM group, which showed ordered myocardial cell arrangement, rare breakage and homogeneous cell nucleus size.4.The expression of mast cells was increased in DM group compared with NC group(p<0.05),and the expression was decreased in Ket group compared with DM group(p<0.05).5. The level of serum TNF-a was increased in DM group compared with NC group(p<0.05),and the level was decreased in Ket group compared with DM group(p<0.05).6. The level of serum ROS was increased in DM group compared with NC group(p<0.05),and the level was decreased in Ket group compared with DM group(p<0.05). 7.Protein expression detected by Western blot:expression of tryptase was increased in DM group compared with NC group(p<0.05),and the expression was reduced in Ket group compared with DM group(p<0.05). Conclusions: 1.Increasing of mast cells and tryptase expression occur in Type 2 diabetic rats myocardial tissue.2.Mast cells and tryptase are involved in the occurrence and development of diabetic cardiomyopathy, which may be partially correlated with the promoting effect of tryptase in the expression of TNF-a and ROS, thus enhancing inflammatory response and oxidative stress.3. Mast cell membrane stabilizer can alleviate diabetic cardiomyopathy,via inhibiting the activity of mast cells and tryptase release and then the subsequent inhibition of inflationary response and oxidative stress. |
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