Abstract
To compare skin irritation and cytotoxicity of anti-wrinkle agents, we examined skin irritation of six anti-wrinkle agents (ascorbic acid, glycolic acid, all trans-retinoic acid, ginseng extract, retinol, EB) in New Zealand white rabbit. Cytotoxicity of these agents was determined by MTT [tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] at multi-time points in cultured HaCaT cell, a human immortalized keratinocyte cell. We then analyzed correlation between skin irritation and cytotoxicity by spearman's rank correlation analysis. All trans-retinoic acid showed the highest primary irritation index (0.92) in skin irritation test. Being all the six agents not irritant, retinal showed the most cytotoxic agents. The correlation between skin irritation and cytotoxicity ($IC_{50}$/ at different time point was 0.814, 0.757, 0.814 and 0.7 at 3, 24, 48 and 72 h, respectively. We also fecund that IC$_{20}$ and IC$_{80}$ of these agents showed similar correlation with skin irritation. These results therefore demonstrated that there is close correlation between skin irritation and cytotoxicity $IC_{50}$/ value by MTT in HaCaT cell at early time points by anti-wrinkle agents or IC$_{20}$ value. $IC_{50}$/ at earily time point or IC$_{20}$ values may be reliable alternative determinant of skin irritation.n.
