Figure 4.

Effects of melatonin on nickel-induced alteration of ISCU1/2 protein levels. The ISCU1/2 protein levels in cells treated with NiCl₂ and melatonin were evaluated by immunofluorescence staining ((a): green—ISCU1/2; blue—DAPI; scale bar—10 μm) and western blot (b). The expression of ISCU1/2 was silenced by transfection with RNA interference (RNAi) construct. The effects of nickel and melatonin on ISCU1/2 protein levels (c) and the activities of aconitase (d) and complex I (e) were evaluated in transfected cells. The error bar reflects the S.E.M. of at least three independent experiments. ^∗P < 0.05 compared with the nickel-free control group, and ^#P < 0.05 compared with the same nickel concentration but with the melatonin-free group.