VEGF antagonism attenuates cerebral ischemia/reperfusion-induced injury via inhibiting endoplasmic reticulum stress-mediated apoptosis

Abstract

Endoplasmic reticulum (ER) stress-mediated apoptosis pathway is considered to play a vital role in mediating stroke and other cerebrovascular diseases. Previous studies have showed that vascular endothelial growth factor (VEGF) antagonism reduced cerebral ischemic-reperfusion (CI/R) damage, but whether attenuation of ER stress-induced apoptosis is contributing to its mechanisms remains elusive. Our study aimed to investigate the protective effect of VEGF antagonism on CI/R-induced injury. First, oxygen-glucose deprivation and re-oxygenation (OGD/R) BEND3 cell model was constructed to estimate small interfering RNA (siRNA)-VEGF on damage of endothelial cells. Next, in animal model, CI/R mice were induced by middle cerebral artery occlusion (MCAO) for 2 h followed by 24 h reperfusion to investigate cerebral tissue damage. For treatment group, mice received 100 μg/kg anti-VEGF antibodies at 30 min before MCAO, followed by 24 h reperfusion. Our findings demonstrated that pre-administration of siRNA-VEGF before OGD/R changed the biological characteristics of BEND3 cells, reversed the levels of X-box binding protein-1 (XBP-1) and glucose-regulated protein 78 (GRP78), showing siRNA-VEGF attenuated, at least in part, the oxidative damage in OGD/R cell by down-regulating ER stress. In mice experiment, pre-administration of anti-VEGF antibody reduced the brain infarct volume and edema extent and improved neurological scores outcome of CI/R injury mice. Pathological and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) staining results also confirmed this protective effect. The expressions of VEGF, CATT/EBP homologous protein (CHOP), inositol requiring enzyme 1α (IRE-1α), and cleaved-caspase12 and c-jun N-terminal kinase (JNK) phosphorylation were also prominently decreased. These results suggested that inhibition of endogenous VEGF attenuates CI/R-induced injury via inhibiting ER stress-mediated apoptosis.