Protective effect of liraglutide on the myocardium of type 2 diabetic rats by inhibiting polyadenosine diphosphate-ribose polymerase-1.

BACKGROUND: In recent years, studies have found that the occurrence and development of diabetic cardiomyopathy (DCM) is closely related to an increase in polyadenosine diphosphate-ribose polymerase-1 (PARP-1) activity. PARP-1 activation could be involved in the pathophysiological process of DCM by promoting oxidative stress, the inflammatory response, apoptosis and myocardial fibrosis.

AIM: To investigate the mechanism of liraglutide in improving myocardial injury in type 2 diabetic rats, further clarified the protective effect of liraglutide on the heart, and provided a new option for the treatment of DCM.

METHODS: Forty healthy male SD rats aged 6 wk were randomly divided into two groups, a normal control group ( n = 10) and a model group ( n = 30), which were fed an ordinary diet and a high-sugar and high-fat diet, respectively. After successful modeling, the rats in the model group were fed a high-glucose and high-fat diet for 4 wk and randomly divided into a model group and an intervention group (further divided into a high-dose group and a low-dose group). The rats were fed a high-glucose and high-fat diet for 8 wk and then started drug intervention. Blood samples were collected from the abdominal aorta to detect fasting blood glucose and lipid profiles. Intact heart tissue was dissected, and its weight was used to calculate the heart weight index. Haematoxylin and eosin staining was used to observe the pathological changes in the myocardium and the expression of PARP-1 in the heart by immunohistochemistry.

RESULTS: The body weight and heart weight index of rats in the model group were significantly increased compared with those in the normal control group, and those in the intervention group were decreased compared with those in the model group, with a more obvious decrease observed in the high-dose group ( P < 0.05). In the model group, myocardial fibers were disordered, and inflammatory cells and interstitial fibrosis were observed. The cardiomyopathy of rats in the intervention group was improved to different degrees, the myocardial fibers were arranged neatly, and the myocardial cells were clearly striated; the improvement was more obvious in the high-dose group. Compared with the normal control group, the expression of PARP-1 in myocardial tissue of the model group was increased, and the difference was statistically significant ( P < 0.05). After liraglutide intervention, compared with the model group, the expression of PARP-1 in myocardial tissue was decreased, and the reduction was more obvious in the high-dose group ( P < 0.05) but still higher than that in the normal control group.

CONCLUSION: Liraglutide may improve myocardial injury in type 2 diabetic rats by inhibiting the expression of myocardial PARP-1 in a dose-dependent manner.