Modification of Sunburn Cell Production in 8-MOP Sensitized Mouse Epidermis: A Method of Assessing UVA Sunscreen Efficacy

The UVA (320–400 nm) photoprotection of four commercially available sunscreens with different sun protection factors was evaluated in 8-methoxypsoralen (8-MOP) treated mouse epidermis with the number of sunburn cells (SBCs) as the end-point. SBC production in 8-MOP sensitized mouse epidermis with and without application of sunscreens is dose-related. The difference between the slopes of the dose-response curves of the control group and the four sunscreens was highly significant (p < 0.001). It appears that the SBC production was modified both by the dose of the UVA irradiation administered and by the UVA photoprotection of four sunscreens. it could be concluded that the number SBCs in 8-MOP sensitized mouse epidermis is a useful parameter to quantify the degree of UVA photoprotection of sunscreens