Figure 10. Effect of anti-acne treatments on O₂ ^•− and IL-8 production in P. acnes-stimulated keratinocytes.

HaCaT cells were untreated (black bar) or incubated for 18 h with P. acnes (MOI of 50) alone (white bar) or with P. acnes in the presence of nicotinamide, zinc sulfate, doxyciclyne, nitroimidazole, retinol, retinoic acid, and isotretinoin at 0.01% (gray bars) or 0.05% (white bars). (A) O₂ ^•− production was determined spectrofluorometrically with DHE, (B) IL-8 concentration was measured by ELISA, (C) and cell death was assessed spectrofluorometrically using YO-PRO-1 as described in Materials and Methods. Data are means±SD of two separate experiments.