AIM To study whether Zige lyophilized powder may improve survival of vascular endothelial cells (EC) following ischemia/reperfusion injury was investigated in this study.METHODS EC cultured from human umbilical vein were sealed in a flowthrough chamber mounted on an inverted microscope and perfused with a constant flow of Krebs medium.After 1 h of equilibration,HUVEC underwent 4 h of hypoxia (H) and 1 h of reoxygenation (R) to mimic ischemia/reperfusion, addition of Zige lyophilized powder to culture medium at start of R.RESULTS H/R caused significant viability loss and an release of LDH increase compared to the normoxic control, 12.5 rag.L-1 Zige lyophilized powder enhanced cell viability(P < 0.05).Also, 49.0, 24.5 and 12.5 rag· L-1 Zige lyophilized powder prevented the decline of SOD activity during H/R(P < 0.05).Furthermore, 24.5 and 12.5 mg·L-1 Zige lyophilized powder significantly inhibited the increase of MDA and NO content.Additionally, apoptotic related protein levels were measured by Western blotting analysis.Bcl-2 protein level increased significantly in the 24.5 and 12.5 mg·L-1 Zige lyophilized powder group.49.0, 24.5 and 12.5 mg·L-1 Zige lyophilized powder significantly decreased Bax level and up-regulated Bcl-2/Bax ratio.Caspase activation and apoptosis were monitored in the reoxygenated cells.49.0 and 24.5 rag· L-1 Zige lyophilized powder decreased caspase 3 expression(P <0.01).CONCLUSION The results indicate that Zige lyophilized powder prevents damage H/R induced to HUVEC,the cytoprotection of Zige lyophilized powder appears to be associated with the enhancement of the ability anti-oxidation and anti-apoptosis.