Particulate matter 2.5 induced hyperpigmentation in reconstructed human epidermis model (MelaKutis®)

[...]external factors can stimulate the melanocytes located in the basal layer to produce melanin, resulting in hyperpigmentation. Zhang et al[2] previously analyzed the components of PM2.5 (collected in Beijing) and revealed that benzo[a]pyrene (BAP) was one of the most abundant and toxic components of PM2.5. [...]we chose BAP as positive control. See PDF] In our study, we found that lower concentrations of PM2.5 (≤12.50 μg/mL) did not cause a significant decrease in the cell viability or a change in the cell morphology of keratinocytes/melanocytes, whereas higher doses led to cell death and cell deformation in a dose-dependent manner. Since this was a qualitative experiment, the selection criteria for PM2.5/BAP concentrations were not so strict. Since no significant change in the cell numbers of the keratinocytes or melanocytes was observed in the cell or MelaKutis® experiments, we speculated that PM2.5 induced hyperpigmentation mainly by increasing the melanin synthesis.