Effects of bevacizumab on morphology and apoptosis of human retinal pigment epithelial cells as well as the expression of apoptosis-related factors / 眼科新进展

ABSTRACT

Objective To investigate the effects of bevacizumab on cell morphology,apoptosis rate and apoptosis-related factors in human retinal pigment epitheliumcells.Methods Human retinal pigment epithelial cells (ARPE-19) were cultured in DMEM/F1 2 medium containing 0.25 g · L-1 bevacizumab and divided into 1-week dosing group and 2-week dosing group according to the different incubation time,respectively.Meanwhile,the control group was set up.Then,the cell morphology and apoptosis of each group were observed by light microscope and flow cytometry,accordingly.The expression levels of apoptosis-promoting genes P53,TP53INP1,Bax and apoptosisinducible gene Bcl-2 mRNA and protein were detected by RT-PCR and Western blot,respectively.Results Light microscopic observation revealed that the cells in the 1-week control group and the 2-week control group showed typical epithelial cell morphology,and were in stone-like,single-layer adherent-like growth.Compared with the control group,part of the cell morphology after bevacizumab treatment changed slightly,and the cells became rounded,the cell body was elongated and the boundary was poor.The apoptotic rates of the 1-week control group,l-week dosing group,2-weekcontrol group and 2-week dosing group were (5.57 ± 1.46) ％,(6.39 ± 1.25) ％,(6.88 ± 1.10)％ and (13.34 ± 1.94)％,respectively,and there was no significant difference in the apoptotic rate between 1-week control group,1-week dosing group and 2-week control group (both P ＞ 0.05),but the apoptotic rate of the 2-week dosing group was significantly higher than that of the 2-week control group,the 1-week dosing group and 1-week control group,and the differences were statistically significant (all P ＜0.01).RT-PCR and Western blot results showed that compared with the 1-week control group,the expression of P53,TP53INP1 and Bax mRNA was up-regulated in 1-week dosing group,but the expression of Bcl-2 mRNA was down-regulated,and the differences were statistically significant (all P ＜ 0.05).The expression levels of P53,TP53INP1 and Bax mRNA in 2-week dosing group were higher than those in 2-week control group and 1-week dosing group,while Bcl-2 mRNA expression was down-regulated,and the differences were statistically significant (all P ＜ 0.05).There was no significant difference in the expression of the above factors in 1-week control group and 2-week control group(all P ＞ 0.05).The protein expressions of above factors were similar to their mRNA expression.Conclusion Bevacizumab can alter the morphology of ARPE-19 ceils,increase the apoptotic rate and up-regulate the expression of apoptosis-promoting factors,but down-regulate the expression of apoptosis-suppression factors in ARPE-19 cells,which may be the reason for the loss of RPE layer in the macula after anti-VEGF therapy.