Figure 6. Direct UVB irradiation decreases, while indirect, keratinocyte-mediated UVB effect increases the relative mRNA expressions of TRP-1 in dedifferentiated melanocytes.

Dedifferentiated melanocytes cultured in Mel-mix medium were irradiated with 20.8 31.2 and 41.6 mJ/cm² doses of UVB. Direct UVB irradiation decreased TRP-1 mRNA expression in melanocytes (A). Keratinocytes were also irradiated with the same UVB doses. Supernatants were collected from irradiated keratinocytes and autologous melanocytes were treated with them. The “indirect” UVB irradiation caused an increase in TRP-1 mRNA expression (B). Values are shown as relative expressions compared to non-irradiated samples (mean±SEM from two independent experiments).