Effect Of Vascular Endothelial Growth Factor(VEGF) On The Expression Of Caspase-3 And The Mechanism Of VEGF On Infarcted Myocardial Cells Under Hypoxic State

Objective:Vascular endothelial growth factor(VEGF) expression in the ischemic myocardium can regulate multiple cellular stress responses, including survival, proliferation, migration, and differentiation[4]. Almost all cells can secrete VEGF in response to hypoxia or other stress conditions. However, the mechanism underlying the complex process by which VEGF protects cardiomyocytes against hypoxic/ ischemic injury and reduces apoptosis has never reported.This study tested Whether VEGF acts at an early stage in the mechanism by which cardiomyocytes are protected against hypoxic/ischemic injury.Materials and Methods:Our studies show that caspase-3 activation induced apoptosis in cardiomyocytes. Pretreatment of cardiomyocytes with VEGF before induction with Co Cl2 upregulated Bcl-2 expression and downregulated caspase-3 expression significantly, leading to a reduction in cell apoptosis [5]. Blockade of the VEGF receptor with Axitinib exacerbated hypoxia-induced myocardial cell apoptosis. It is worth noting that this effect may be caused directly by a modulatory effect of VEGF on calcium uptake by the sarcoplasmic reticulum rather than by hypoxia-induced apoptosis.Results:1. The modal of rat acute myocardial infarction:The modal was successfully established by ligaturing the LAD. The common causes of death in the experiment were improper anesthesia, bleeding, nerve damage, lung injury, airway obstruction, arrhythmia, infection, etc.2. Hypoxia model of myocardial cell: Co Cl2 induced hypoxia myocardial cell model with concentration of 50 u M,Immunohistochemistry results:The distribution of HIF-1a and Caspase-3 in hypoxic myocardial cells was obviously abnormal.Analysis and results of fluorescence quantitative PCR technique:The expression of Caspase-3 and HIF-1a was significantly increased.3. Anoxic myocardial cells:Results of Western blotting:Protein levels of HIF-1a, VEGF, cleaved-caspase-3, SERCA2 a, PLB and Ca MK-II were significantly higher than normal myocardial cells;Analysis and results of fluorescence quantitative PCR technique:The expression level of HIF-1a, VEGF, cleaved-caspase-3, SERCA2 a, PLB and Ca MK-II were significantly higher than normal myocardial cells.4. Anoxic myocardial cells, hypoxia +VEGF, hypoxia +AEE 788:Results of Western blotting:The protein levels of HIF1 a, VEGF, cleaved-caspase-3, SERCA2 a, PLB, Ca MK-II and were highest in the hypoxia+VEGF group,The expression of the above protein level were lowest in the hypoxia +AEE788 groups. Analysis and results of fluorescence quantitative PCR technique have similar results.5. Determination of intracellular calcium by fluorescent indicator AM Fura-2 method:The ability of Fura-2 AM binding Ca2+ in anoxic cardiomyocytes was decreased, and the hypoxia+AEE 788 group was the weakest.Conclusions:In this study, we show for the first time that VEGF acts at an early stage in the mechanism by which cardiomyocytes are protected against hypoxic/ischemic injury.It may be potential targets for the reversion of myocardial cell injury after acute myocardial infarction or ischemia-reperfusion.