| Objective: Diabetes cardiomyopathy with diastolic and (or) systolic dysfunction for clinical manifestation, which can cause heart failure, arrhythmia, angina, cardiac shock and sudden death ,is one of the main complications of diabetes and the main cause of the diabetic died. It is characterized by myocardial cell metabolism disorders, myocardial cell hypertrophy hyperplasia, myocardial fibrosis, myocardial cell apoptosis, myocardial cell function drops, cell level such as calcium transshipment defects. Glucose use obstacles, fatty acid use increased are both the reasons of myocardial cell disorder, which are the first change of the function of the diabetes cardiomyopathy. Glucagon, which promotes glycogenolysis, gluconeogenesis and inhibits glycogenesis, is a peptide hormone secreted by pancreatic alpha cell. There are a large number of studies have shown, diabetics has glucagonemia which is negatively correlated with insulin sensitivity. And it is confirmed that glucagonemia is one of the pathogenesis of diabetes. However, the studies of glucagonemia was focused on promoting glucose levels, the role of glucagonemia in complications of diabetes is uncertain, especially in diabetes cardiomyopathy. This study is going to discuss the effect of glucagonemia to the expression ofα-subunit of the insulin receptor,β-subunit of the insulin receptor, glucose transporter-4 (GLUT-4) in cardiac myocytes of neonatal rats. Then we will go on studying the effect of glucagonemia to diabetes and diabetes cardiomyopathy, to find a new way for diabetes treatment.Methods: myocardial cells of neonatal rats were isolated by collagenase sequential digestion and different speed adherence method and cultured in vitro. After seventy-two hours of culture, the culture solution was changed into Dulbecco modified Eagle medium with blood serum. The cells cultured in vitro were assigned into 3 groups, each group included 9 wells, and there are 27 wells in all. During changed the medium, Administratied them. The first group was the normal model with nothing. The second was glucagon group administrated glucagon at concentrations 100ng/l. The third was the high glucose group administrated glucagon at concentrations 1000ng/ml. The morphology of cardiac myocytes was observed with inverted phase contrast microscope everyday after administration and the indexes were detected after forty-eight hours of administration. Separated every group into 3 parts equally, now there are 9 groups: 1A,1B,1C,2A,2B,2C,3A,3B,3C. In every group,α-subunit of the insulin receptor is detected in A,β-subunit of the insulin receptor is detected in B, GLUT-4 is detected in C. (1) Contrast to the morphology of cardiac myocytes. (2) The expression ofα-subunit of the insulin receptor,β-subunit of the insulin receptor, GLUT-4 in cardiac myocytes is detected by immunohistochemical staining (IHCS). (3) The photo of IHCS was dealt with by Image-Pro-Plus 6.0, and semi-quantitative analysising.In the end analyse the data with the software of SPSS 13.0.Results: (1) We cultured cardiac myocytes of the neonatal rats successfully.(2) The expression ofα-subunit of the insulin receptor,β-subunit of the insulin receptor, GLUT-4 in cardiac myocytes is described by mean desity in 9 groups. The expression ofα-subunit of the insulin receptor (F=78.504,P=0.000),β-subunit of the insulin receptor (F=42.700,P=0.000), GLUT-4 (F=39.449,P=0.000) are all significant difference in the first group (normal model with nothing), the second group (100ng/l glucagons), the third (1000ng/ml glucose) group. Multiple compare to the first group by LSD-t, the expression ofα-subunit of the insulin receptor (P=0.000),β-subunit of the insulin receptor (P=0.000), GLUT-4(P=0.000) in cardiac myocytes on the second (100ng/l glucagons) group is reduced evidently. Multiple compare to the first group by LSD-t, the expression ofα-subunit of the insulin receptor (P=0.000),β-subunit of the insulin receptor (P=0.000), GLUT-4(P=0.000) in cardiac myocytes on the third (1000ng/ml glucose) group is reduced evidently. Multiple compare to the second (100ng/l glucagons) group by LSD-t, the expression ofα-subunit of the insulin receptor (P=0.020),β-subunit of the insulin receptor (P=0.027), GLUT-4 (P=0.010) in cardiac myocytes on the third (1000ng/ml glucose) group is reduced evidently.Conclusion: Theα-subunit of the insulin receptor,β-subunit of the insulin receptor, GLUT-4 in cardiac myocytes of neonatal rats is reduced expression by glucagonemia. And the more glucagonemia, the more reducing. Glucagonemia may act on transduction of insulin receptor in myocardial cells and transport of glucose, causing the glucose of myocardial cells disorder and make myocardial cell metabolism disorder. It may play an important role in the development of diabetes cardiomyopathy.
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