Docosahexaenoic acid protects human retinal pigment epithelial cells against oxidative stress-induced apoptosis / 中国病理生理杂志

ABSTRACT

AIM:To observe the effect of docosahexaenoic acid ( DHA) on H2 O2-induced apoptosis in human retinal pigment epithelium cells and its molecular mechanism .METHODS: Human retinal pigment epithelium cell line ARPE-19 was cultured in vitro, and 12.5 mmol/L H2 O2 was used to mimic the oxidative stress condition .The cells were treated with 30~100μmol/L DHA for 4~24 h.The expression of heme oxygenase-1 (HO-1) at mRNA and protein levels was detected by real-time PCR and Western blot , respectively .The enzymic activity of HO-1 was measured by colorimetry . Production of reactive oxygen species ( ROS) was determined by fluorescent probe .Activation of NF-E2-related factor 2 (Nrf2) was examined by immunofluorescence method .Apoptosis of ARPE-19 cells was analyzed by flow cytometry .RE-SULTSThe mRNA and protein expression and the enzymic activity of HO-1 were significantly increased in the ARPE-19 cells after DHA treatment .Meanwhile , nuclear translocation of Nrf 2 was also observed .Apoptosis appeared and ROS was produced upon H2O2 incubation.In contrast, DHA at 100 μmol/L significantly abrogated H2O2-induced apoptosis and ROS production.Furthermore, silencing of HO-1 by specific siRNA, or treatment with ZnPP, an inhibitor of HO-1, partly counteracted the protective effect against H 2 O2-induced apoptosis and ROS production .CONCLUSION: DHA protects retinal pigment epithelial cells against oxidative stress via induction of heme oxygenase -1 expression after Nrf2 activation .