Curcumin attenuates UVB-induced oxidative stress and cell death by activating Nrf2 signaling / 中华放射医学与防护杂志

ABSTRACT

Objective To investigate the effects of curcumin on UVB-induced elevation of cellular ROS level and cell death and to explore the involvement of transcription factor Nrf2.Methods Mouse embryonic fibroblasts (MEFs) were pretreated with or without curcumin then irradiated with UVB.The cell viability,cellular ROS level and protein levels of Nrf2 and HO1 were determined by MTT assay,DCFH fluorescence and Western blotting,respectively.These measurements were also performed in Nrf2 (-/-) MEFs.Results UVB irradiation elevated cellular ROS level and decreased cell viability of MEFs(t =16.65,15.89,P ＜ 0.05),while the curcumin pretreatment significantly attenuated the deleterious effects of UVB(t =11.88,3.77,P ＜ 0.05).UVB irradiation moderately increased the protein levels of Nrf2 and HO1 and activated JNK and ERK.The curcumin pretreatment led to more remarked elevation of Nrf2 and HO1 proteins,while inhibited UVB-activated JNK and ERK,but it had little effect on p38MAPK.In contrast,Nrf2 (-/-) MEFs showed significantly decrease in Nrf2 and HO1 expressions and were more susceptible to UVB-induced damages.Interestingly,the protective effects of curcumin were also greatly compromised in Nrf2 (-/-) MEFs (t =16.73,-8.23,P ＜ 0.05).Conclusions Curcumin can attenuate UVB-induced oxidative damages in MEFs by activating Nrf2 signaling.