＜正＞ Background Adrenomedullin is a potent vasodilating peptide and involved in many cardiovascular diseases.However,whether adrenomedullin is involved in the pathogenesis of diabetic cardiomyopathy is still unknown.Our aim was tocharacterize the expression pattern of adrenomedullin in the myocardium of streptozotocin-induced diabetic rats.Methods The weight, blood glucose, and urine glucose of 20 streptozotocin-induced diabetic rats were measuredbefore and after model induction in the diabetic and control groups.The alteration of the adrenomedullin expression wasexplored in the left ventricular myocardium in both groups by immunohistochemistry.Changes in heart ultrastructure werealso analyzed by using hemotoxylin and eosin staining and transmission electron microscopy.All data were analyzed bythe independent samples ttest.Results The data of weight, blood glucose, and urine glucose had no significant difference between the control and thediabetic groups before animal model induction.Four weeks after the induction of diabetes, the differences between thetwo groups in weight, blood glucose, and urine glucose were distinct.When compared with the control group, the diabeticgroup showed ultrastructural changes including hypertrophy, fibrosis, myofibrillar disarrangements, mitochondrialdisruption, and increase in nuclear membrane invaginations.A significant decrease of adrenomedullin expression wasalso observed in cardiac myocytes of the diabetic rats（P＜0.01）.Conclusions Our study provides experimental evidence that hyperglycemia could damage cardiac myocytes.Down-regulation of cardioprotective peptide adrenomedullin in the myocardium of streptozotocin-induced diabetic ratsmay contribute to the diabetic cardiomyopathy and left ventricular dysfunction.
展开▼
