Fig. 1

Figure 1. 5-HT induces melanogenesis in B16F10 and zebrafish embryos: (a) Masson–Fonta staining of B16F10 cells to show the melanocytes morphology and melanin content with the treatment of different concentrations of 5-HT (10, 50, and 100 μM), α-MSH (50 nM) was used as a positive control. Scale bar, 50 μm; (b,c) relative tyrosinase activity (b) and melanin content (c) in B16F10 cells treated with 5-HT (10, 50, and 100 μM) (n = 6). The photos of melanin precipitation in the tube are at the top of the diagram (c); (d) Western blot shows the protein expression of melanin synthesis, MITF, and TYR in B16F10 cells treated with 5-HT (10, 50, and 100 μM); (e) the drug treatment strategy in zebrafish, 0.2 mM PTU (9–35 hpf) resulted in depigmentation in zebrafish, then 0.2 mM PTU or specific drug was added to explore the recovery of pigment in the zebrafish embryos at 60 hpf; (f) the morphology of melanocytes in zebrafish embryos at 60 hpf treated with 5-HT (0.1, 0.5, and 1 mM) from 35–60 hpf. The left column shows the whole view of zebrafish embryos (lateral view). The right three columns show the amplification photos of head (lateral view), trunk (lateral view), and head (dorsal view). Scale bar, 100 μm. * (p < 0.05) and ** (p < 0.01) compared to control group.