Tranexamic Acid Diminishes Laser-Induced Melanogenesis

Background:The treatment of post-inflammatory hyperpigmentation (PIH) remains challenging.Tranexamic acid, a well-known anti-fibrinolytic drug, has recently demonstrated a curative effect towards melasma and ultraviolet-induced PIH in Asian countries.However, the precise mechanism of its inhibitory effect on melanogenesis is not fully understood.Objective: In order to clarify the inhibitory effect of tranexamic acid on PIH, we investigated its effects on mouse melanocytes (i.e., melan-a cells) and human melanocytes.Methods: Melan-a cells and human melanocytes were cultured with fractional CO2 laser-treated keratinocyte-conditioned media.Melanin content and tyrosinase activity were evaluated in cells treated with or without tranexamic acid.Protein levels of tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 were evaluated in melan-a cells.Signaling pathway molecules involved in melanogenesis in melanoma cells were also investigated.Results: Tranexamic acid-treated melanocytes exhibited reduced melanin content and tyrosinase activity.Tranexamic acid also decreased tyrosinase, TRP-1, and TRP-2 protein levels.This inhibitory effect on melanogenesis was considered to be involved in extracellular signal-regulated kinase signaling pathways and subsequently microphthalmia-associated transcription fac-tor degradation.Conclusion: Tranexamic acid may be an attractive candidate for the treatment of PIH. (