Expression of bax and bcl 2 during cultured human retinal pigment epithelial cell apoptosis

Objective To investigate the molecular mechanism of apoptosis in cultured human retinal pigment epithelial (RPE) cells. Methods The growth media of confluency human RPE cells were replaced with a daunoblastina containing one at a dose of 180 μg/L,and the cells were incubated for 12 hr at 37℃.After incubation with the drug,the medium was withdrawn,fresh medium was added and incubation was carried out for an additional 24 hr.Apoptosis was monitored by light microscopy,enzyme linked immunosorbent assay(ELISA)and terminal deoxynucleotidyl transferase mediated biotin dUTP nick end labelling(TUNEL)staining.The expression of bax and bcl 2 were evaluated by immuncoytochemical staining with anti human bcl 2 and bax antibodies. Results After the RPE cells treated with daunoblastina,shrinkage of cytoplasm and nucleus was identified.The ratio of nucleus to cytoplasm was increased.TUNEL staining showed that many cells were positive staining.The amount of apoptotic cells was directly proportional to the drug dose.The integral optical desity values for expression of bax inereased by 22.0%(P 0.05), and that of bcl 2 did not change significantly(P0.05). Conclusions During human RPE cell apoptosis induced by daunoblastina,overexpression of bax or low bcl 2/bax ratio were demonstrated.The results suggest that bax and bcl 2 gene expression could play a role in regulation of RPE cell apoptosis.