Abstract: Objective To explore the effect of upregulating CXC-chemokine receptor 7 (CXCR7) in endothelial progenitor cells (EPCs) on angiogenesis after cerebral ischemia-reperfusion injury. Methods EPCs were isolated and cultured from human umbilical cord blood and identified. Then, the EPCs were transfected with CXCR7 overexpression lentiviral vector, and the expression of CXCR7 was identified with real-time PCR and Western blotting. The tube-like structure formation and apoptosis of EPCs under oxidized low density lipoprotein (ox-LDL) were detected with tube-like structure formation test and Annexin V/PI staining. Cerebral ischemia-reperfusion injury model in rats was established, and the qualified model rats were randomly divided into three groups after 24 hours reperfusion: PBS group (n = 12) was injected with phosphate buffers through tail vein, control group (n = 12) was injected the EPCs infected with control lentiviral vector, and CXCR7 group (n = 12) was injected with EPCs infected with CXCR7 overexpression lentiviral vector. Neurological function scores were determined seven and 14 days after transplantation. The cerebral infarct volume was measured, the number of GFP-positive cells in the ischemic site and the density of capillary were observed. Results The expression of CXCR7 in EPCs increased after transfection (P < 0.01). Overexpression of CXCR7 improved tube formation and reduced apoptosis of EPCs under ox-LDL (P < 0.05). Compared with PBS and control groups , neurological function improved in CXCR7 group, with less infarct volume, more GFP-positive cells and density of capillary (P < 0.05). Conclusion Up-regulating CXCR7 can improve the survival and angiogenesis of EPCs, and improve the repair of cerebral ischemia-reperfusion injury.

Key words: cerebral ischemia-reperfusion, endothelial progenitor cells, CXC-chemokine receptor 7, angiogenesis, rats