Effects Of Rhnrg-1β On Angiogenesis And Vegf Expression In Ischemic Myocardium Of Rats After Acute Myocardial Infarction

Objective: To explore the effects and possible mechanism of recombinant human Neuregulin-1βon cardiac function of acute myocardial infarction (AMI) rats, the angiogenesis and the expression of vascular endothelial growth factor (VEGF) in ischemic myocardium.Methods: AMI model was established with Sprague-Dawley rats by ligation of the left anterior descending coronary artery.The rats which survived 24 hours after surgery were randomly separated into 2 groups: rhNrg-1βtreatment group with caudal vein injection of rhNrg-1βat a dose of l0μg·kg - 1·d– 1 for 5 consecutive days and the myocardial infarction (MI) control group. Another sham operation group underwent thoracic incision without ligation of left anterior descending coronary artery. MI control group and sham operation group were simultaneously administered with 0.1mol/L PBS. After routine feed and water for 28 days, cardiac function of different groups were evaluated by echocardiography. After that, the rats were soon executed to detect the weight and mass index of left ventricular. Densities of new collateral microvessel were measured byⅧfactor immunohistochemical analysis. Western blotting was adopted to observe VEGF expression in the ischemic myocardium of AMI rats.Results: Compared with the MI control group, cardiac function of the rhNrg-1βtreatment group obviously improved; Compared with the sham operation group, a large number of new blood vessels in the proliferative stage can be found in the infarction border zone of both MI group and rhNrg-1βtreatment group, and capillary density in the rhNrg-1βtreatment group was significantly greater than that in the MI control group; Besides, the expression of VEGF protein significantly increased in the infarction border zone of MI group and rhNrg-1βtreatment group, and expression level in the MI group was much less than that in the rhNrg-1βtreatment group.Conclusions: rhNrg-1βincrease expression of VEGF protein in ischemic myocardium of AMI rats which can promote angiogenesis and collateral circulation to protect ischemic myocardium and improve cardiac function.