Effects Of Bezafibrate On The Apoptosis Of Cultured Endothelial Cells Induced By Ox-LDL And The Role Of LOX-1

Objective: To observe the influence of oxidized low density lipoprotein (ox-LDL) on the apoptosis and the expression of LOX-1 of cultured human umbilical vein endothelial cells(HUVECs).To investigate the influence and the mechanism of bezafibrate,which is agonist of peroxisome proliferator-activated receptorα,on the expression of LOX-1 and apoptosis of cultured endothelial cells induced by ox-LDL.Methods: Human umbilical vein endothelial cells were isolated from freshly obtained human umbilical cord by collagenase treatment.The cells were cultured in DMEM culture medium. HUVECs from 4,5 generations are applied to experiment.Six groups were selected for the study:①control group: the normal cultured HUVECs;②ox-LDLgroup:HUVECs were coincubated with 50mg/L ox-LDL for 24h;③low-concentration bezafibrate group: HUVECs were coincubated with 50umol/L bezafibrate for 2h,then as same as ox-LDL group;④middle-concentration bezafibrate group: HUVECs were coincubated with 100umol/L bezafibrate for 2h,then as same as low-concentration bezafibrate group;⑤high-concentration bezafibrate group: HUVECs were coincubated with 200umol/L bezafibrate for 2h,then as same as low-concentration bezafibrate group ;⑥250μg/mL Poly ( 1 ) + middle-concentration bezafibrate group:HUVECs were coincubated with 250μg/mL Poly(1)for 2h,then as same as middle-concentration bezafibrate group.LOX-1 mRNA,Bcl-2 mRNA and Bax mRNA were detected by RT-PCR;LOX-1 protein were detected by Wester-blot;cell apoptosis were obtained through flow-cytometry.Results: (1) Compared with the control group,ox-LDL could increase LOX-1 mRNA and protein expression(P<0.01),bezafibrate decrease the expression of LOX-1 in concentration- dependent manner(P <0.05), preincubation of HUVECs with polyinosinic acid for 2 h, the expression of LOX-1 decreased compared with middle-concentration bezafibrate group(P<0.05).(2) Compared with the control group,ox-LDL could increase the apoptosis(P<0.05), alterate the expression of Bcl-2 (P<0.05),increase the expression of Bax(P<0.05), decrease the Bcl-2/Bax ration(P<0.05), bezafibrate could decrease the apoptosis , increase the expression of Bcl-2 and decrease the expression of Bax in a concentration dependent manner(P<0.05), preincubation of HUVECs with polyinosinic acid for 2 h, the apoptosis decreased ,the expression of Bcl-2 decreased and the the expression of Bax increased(P<0.05). Conclusions: ox-LDL could increase the expression of LOX-1,increase the apoptosis ,alterate the expression of Bcl-2,increase the expression of Bax, decrease the Bcl-2/Bax ration, wich injured the endothelial cells . Bezafibrate can decrease the apoptosis of HUVECs activated by ox-LDL by decrease the expression of LOX-1,wich may be responsible for bezafibrate to prevent and treat atherosclerosis.