Electroacupuncture pretreatment promotes angiogenesis via hypoxia-inducible factor 1α and vascular endothelial growth factor in a rat model of chronic myocardial ischemia

Objective: Electroacupuncture (EA) pretreatment appears useful in the treatment of chronic myocardial ischemia (CMI). The goal of this study was to investigate the effect of EA preconditioning on the regulation of hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) proteins in a CMI model of vascular regeneration. Methods: A CMI model was established by subcutaneous injection of isoprinosine hydrochloride (ISO) for 14 days in 45 Wistar rats, which had been randomly divided into a model group ( n = 15), a CMI group pretreated with sham EA for 21 days (CMI + Sham group, n = 15) and a CMI group pretreated with verum EA for 21 days (CMI + EA, n = 15) prior to modeling. An additional 15 Wistar rats received 0.9% sodium chloride via intraperitoneal injection for 14 consecutive days (control group). Serum levels of VEGF and HIF-1α were measured by ELISA, while protein expression of VEGF and HIF-1α in the area of myocardial infarction was measured by Western blotting. The area of myocardial infarction and fibrosis of the myocardial tissue in the study groups were visualized by hematoxylin-eosin (HE) staining and Masson staining, respectively. Results: EA pretreatment improved cardiac function by regulating left ventricular end-diastolic diameter and left ventricular end-systolic diameter, left ventricular ejection fraction and the ST segment voltage of the electrocardiogram. EA pretreatment promoted vascular regeneration by increasing serum levels of VEGF and HIF-1α and by increasing protein expression of HIF-1α and VEGF in the infarcted region of the myocardium, leading to a reduction in the area of myocardial infarction on HE staining and reduction of myocardial fibrosis on Masson staining. Conclusion: EA pretreatment promotes protein expression of HIF-1α and VEGF in areas of ischemic myocardium, which may represent useful biomarkers for coronary collateral establishment and offer potential targets for therapeutic angiogenesis in patients with CMI.