Figure 4. Effects of 200 μM melatonin and 5 nM IL-1β for 24 h on collagen II (COL2), aggrecan and MMP-3 in NPCs detected by immunofluorescence. (A) Representative images of immunofluorescence of COL2 in NPCs photographed by fluorescence microscopy (scale bar=100μm). (B) Semi-quantitative analysis of COL2 fluorescence intensity (n=3). (C) Representative images of immunofluorescence of aggrecan in NPCs photographed by fluorescence microscopy (scale bar=100μm). (D) Semi-quantitative analysis of aggrecan fluorescence intensity (n=3). (E) Representative images of immunofluorescence of MMP-3 in NPCs photographed by fluorescence microscopy (scale bar=100μm). (F) Semi-quantitative analysis of MMP-3 fluorescence intensity (n=3). The values are expressed as mean ± SD. *P<0.05 vs control group; **P<0.01 vs control group; ##P<0.01 vs IL-1β group.