Research Article
Polygonum multiflorum Thunb. Extract Stimulates Melanogenesis by Induction of COX2 Expression through the Activation of p38 MAPK in B16F10 Mouse Melanoma Cells
Figure 5
PME treatment enhanced melanogenesis by induction of COX2 expression through the activation of p38 MAPK in B16F10 cells. (a) B16F10 cells were pretreated with 10 μM SB 203580 (SB) for 1 h and then treated with 10 μg/mL of PME for 24 h. The protein levels of COX2, tyrosinase, and MiTF were estimated by western blotting. The relative expression levels of the target proteins were normalized to that of β-actin and quantified using the ImageJ software. Control (Con): vehicle only. Data are presented as mean ± SEM of three to four independent experiments. , vs. control or PME. (b) B16F10 cells were seeded in 4-well chambers and pretreated with 10 μM SB for 1 h, followed by further treatment with 10 μg/mL PME for 24 h. Immunocytochemistry was performed using an anti-tyrosinase antibody and Alexa Fluor 546-conjugated secondary antibody. The nuclei were counterstained with DAPI (blue) (original magnification, 400x; scale bars represent 20 μm). (c, d) B16F10 cells were pretreated with 10 μM SB for 1 h and then treated with 10 μg/mL PME for 96 h. The tyrosinase activity (c) and melanin content (d) in cell lysates were analyzed by measuring the absorbance at 475 nm and 490 nm, respectively. Data are presented as the mean ± SEM of three to four independent experiments. , vs. control or PME.
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