[The relationship of blood glucose and the expression of insulin-like growth factor-1 receptor mRNA in diabetic cardiomyopathy: a preliminary study with rats].

ABSTRACT

OBJECTIVE: To investigate the role of insulin-like growth factor-1 receptor mRNA (IGF-1R mRNA) in diabetic cardiomyopathy. METHODS: Alloxan of the doses of 150 and 200 mg/kg was injected intraperitoneally into 20 male Wistar rats respectively so as to establish type 1 diabetes mellitus models (Groups B and C). The rats were used as normal controls (Groups A). Three months later the rats were killed and blood samples were collected to undergo examination of plasma glucose, insulin, glycated hemoglobin (HbA1c), and C peptide. The hearts were taken out to undergo light and transmission electron microscopy and in situ hybridization to detect the expression of IGF-1R mRNA in the myocardium. RESULTS: The levels of plasma glucose, HbA1c, insulin and C peptide of Groups B and C were all significantly higher than those of Group A (all P < 0.01), and the levels of plasma glucose, HbA1c, insulin and C peptide of Group C being significantly higher than those of Group B too (all P < 0.01). Expression of IGF-1R mRNA was found in the myocardium of Groups A, B and C with the distribution areas of 20%, 30%, and 38% respectively. The expression of IGF-1R mRNA in myocardium was positively correlated with blood glucose and HbA1c (r = 0.869, 0.865, both P < 0.01). CONCLUSION: The increased expression of IGF-1R mRNA in the myocardium may play an important role in the progression of diabetic cardiomyopathy.