The mitigation mechanism of morin on PM 2.5 -induced apoptosis by inhibiting mitochondrial damage via the ROS/ERK signaling pathway in human HaCaT keratinocytes

Particulate matter 2.5 (PM2.5) can penetrate the human skin, causing inflammatory disease, senescence, and carcinogenesis. This study assessed the effects of morin on PM2.5-induced apoptosis of HaCaT human keratinocytes. According to our results, morin at concentrations up to 12 µg/mL did not exhibit any harmful effects on cells and effectively reduced the generation of reactive oxygen species induced by PM2.5. Furthermore, morin significantly inhibited PM2.5-induced macromolecular damage, mitochondrial damage, and expression of pro-apoptotic proteins. Moreover, the cytoprotective effects of morin correlated with the activation of the transcription factor nuclear factor erythroid 2-related factor 2 and heme oxygenase-1 expression. The results of our experiments using a mitogen-activated protein kinase kinase inhibitor indicated that morin protected cells from apoptosis by the extracellular signal-regulated kinase pathway. Morin mitigated skin damage caused by PM2.5 via attenuation of oxidative stress, mitochondrial dysfunction, and apoptosis.