[Study on the change of myocardial cell and matrix in the rats with insulin resistance and type 2 diabetes mellitus].

ABSTRACT

OBJECTIVE: To explore the injury of insulin resistance on cardiac muscle cell and matrix, and the relationship between insulin resistance and diabetic cardiomyopathy. METHODS: Twenty four Wistar rats of 6 months were randomly divided into normal control (N), insulin resistance group (I), diabetic group (D). Euglycemic insulin clamp technique (EICT) was used to determine insulin resistance (IR). Cadiocyte apoptosis was evaluated by TUNEL. Heart weight (HW) and body weight (BW) were measured to calculate HW/BW. Ultra-microstructure of cardiac muscle cell and structure of heart was observed. Masson dyeing, hydroxyproline detection and immunohistochemistry were used to measure the levels of collagen protein. RESULTS: Compared with controls, GIR decreased remarkably in D group and I group (P < 0.01). The number of apoptosis cell in I group was lower than that of D group (P < 0.01), and higher than that of N group (P < 0.01). Injury change of ultramicrostructure of myocardial cell was observed in the rats with type 2 diabetes mellitus or insulin resistance. Interstitial fibrosis of heart occurred in D group and I group. Content of Hydroxyproline, the level of I , III type of collagen, and the total level of collagen in I group were lower than those in D group, and higher than those in N group (P < 0.05). CONCLUSION: Insulin resistance in the rats with type 2 diabetes mellitus or insulin resistance can injury myocardial cell and matrix.