Abstract: Abstract: Objective To study the early protective effect of NADPH on human umbilical vein endothelial cells (HUVECs) and the expression of occludin and MMP9 induced by oxygen glucose deprivation and reoxygenation (OGD/R). Methods HUVECs were cultured and divided into blank control group, OGD/R group and OGD/R+NADPH 20 μmol/L group. The proliferation of HUVECs after treatment was detected by CCK- 8 assay. The cytotoxicity was detected by LDH release assay. The morphological changes of HUVECs were observed by inverted microscope. Superoxide dismutase (SOD MDA) activity and malondialdehyde (MDA) were detected by commercially available kit. The expressions of occludin and MMP9 were detected by Western blot assay. Results Compared with the OGD/R, NADPH enhanced the cell viability significantly (P＜0.05), reduced the release of LDH (P＜0.05), promoted the maintance of HUVECs morphology, reduced MDA generation (P＜0.05) and increased SOD activity (P＜0.05). Following OGD/R，the treatment of NADPH can inhibit MMP9 level (P＜0.05) and promote the recovery of occludin level (P＜0.05). Conclusion NADPH can protect HUVECs from the damage induced by OGD/R by reducing oxidative stress and regulating the expressions of MMP9 and occludin.

Key words: NADPH, endothelial cells, umbilical veins, oxidative stress, matrix metalloproteinase 9, occludin, oxygen glucose deprivation and reoxygenation