OBJECTIVE  To verify whether tranexamic acid(TXA) nanoemulsion affects the occurrence and development of melasma through autophagy pathway.

METHODS  B16 cell(melanoma) were treated with TXA nanoemulsion at different concentrations. The cell proliferation, melanin content, tyrosinase activity and the expression of cell-related proteins were detected by the MTT assay, NaOH lysis method, L-Dopa oxidation method, and immunofluorescence and Western blotting.

RESULTS The results of MTT showed that TXA nanoemulsion at different concentrations could inhibit the growth of B16 cells, and significantly reduce melanin production and inhibit intracellular tyrosinase activity. Western blotting results showed that TXA nanoemulsion could down-regulate the expression of melanin-producing proteins(MIFF, TRP1/2) and up-regulate the expression of autophagy-related marker proteins(Beclin1, ATG12, LC3). Immunofluorescence observation results showed that TXA nanoemulsion could up-regulate the expression of LC3 protein in the cytoplasm of B16 cells.

CONCLUSION  TXA nanoemulsion can affect the expression of related proteins by activating the autophagy system of cells and reduce melanosis, so as to achieve effective treatment of melasma.