Role of calcitonin gene-related peptide and IP3 pathway in ischemic preconditioning in isolated perfused hearts of rats with type 1 diabetes mellitus / 上海交通大学学报（医学版）

ABSTRACT

Objective To investigate the role of calcitonin gene-related peptide(CGRP)and IP3 signal pathway in ischemic preconditioning(IPC)in the isolated perfused hearts of rats with type 1 diabetes mellitus. Methods Type 1 diabetes mellitus rat models were established in 80 SD rats,and were randomly divided into 4 week(D-4w)group and 8 week (D-8w)group.These two groups were randomly subdivided into model control(D-Cont)group,type 1 diabetes mellitus ischemia-reperfusion(IR)group,IPC group,CGRP(IPC+CGRP)group and IP3 inhibitor wortmanin(IPC+WMN) group.Another 16 rats were served as normal control(N-Cont)group.In vitro perfusion models of isolated hearts were established by Langendorff methods,and CGRP or wortmanin(WMN)were administered during perfusion.The left ventricle function of isolated heart in each group was monitored by multichannel biosignal analysis system,and coronary artery flow was recorded.The serum CGRP levels were detected by ELISA.The activity of lactate dehydrogenase(LDH)and creatine kinase(CK)in effluent of coronary artery was detected by biochemical method.The size of myocardial infarction was determined by NBT staining,and apoptosis of cadiocytes was detected by TUNEL method. Results Compared with N- Cont group,the CGRP level in serum of rats with type 1 diabetes mellitus decreased with time,the basic left ventricle function decreased,while the activity of LDH and CK in effluent of coronary artery,size of myocardial infarction and cardiomyocyte apoptosis index increased(P<0.05).Compared with N-Cont group,the left ventricle function was significantly lower in IR group,and more severe myocardial damage was observed.IPC improved myocardial damage of D-4w IR group,while had no protection on D-8w IR group.Compared with IPC group,the left ventricle function was significantly improved in IPC+CGRP group.IPC+WMN blocked the myocardial protection of D-4w group from IPC.Conclusion CGRP and IP3 signal pathway are involved in the protection provided by IPC in isolated hearts of rats with type 1 diabetes mellitus.