The protective effect and action mechanisms of Icariin on oxidative injury of HUVEC induced by H2 02

Aim To investigate the protective effects of icariin（ICA） on oxidative injury of human umbilical vascu- lar endothelial cells （HUVEC） caused by H202 and analysis action machenisms of ICA. Methods HUVEC were cultured in DMEM medium with 10% fetal bovine serum and 1% antibiotic mixture comprising penicillin and strep- tomycin, at 37℃; with 5% CO2 in vitro. The model of oxidative injury was established by H202 （ 750 μmol · L^-1 ）. The cells were divided into six groups： control group, H202 group, H202 ＋ ICA（ 10-8, 10-7, 10-6 tool · L^-1 ） group and H202 ＋ DMSO （solvent） ; HUVEC were treated with different concentration ICA according to grou- os before 12h H202 treatment and cultured for 12, 24 and 36h respectively, the cell vitality （OD value） and the level of ROS was measured by MTT and ELISA. The apoptosis and death of HUVEC were detected using Annexin V-FITC/PI kit. Real Time RT-PCR was used to detect Bcl-2 and Bax mRNA expression in the HUVEC. Results Compared with control group, cell vitality significantly declined （P 〈 0.01 ） , the level of ROS and the number of apoptotic HUVEC notably increased （P 〈 0. 01 ） in H202 group. Compared with H202 group, ICA treatment could increase HUVEC vitality and reduce level of ROS （P 〈 0.01 or P 〈 0. 05） with manners of time-dependence and dose-dependence,ICA treatment could decrease the apoptosis and death rate of HUVEC （P 〈 0.01 ）. ICA treat- ment could also down-regulate the expression of Bax mRNA （ P 〈 0.05 ） and up-regulate the expression of Bcl-2 （ P 〈 0.05）. Conclusion The ICA can alleviate the oxidative injury of HUVEC induced by H202 treatment. The ac- tion mechanisms of ICA may, at least partly, be related to inhibit HUVEC apoptosis caused by H202 treatment through up-regulation of expression of Bcl-2 and down-regulation of expression of Bax mRNA.