087 Effect of minoxidil on proliferation and apoptosis in human dermal papilla cells.

Jun-Kyu Oh, Ji-Hyun Han, Kyu-Han Kim, Jin-Ho Chung, Kwang-Hyun Cho, Hee-Chul Eun. Department of dermatology, Seoul national university, Seoul, Korea.

Minoxidil promotes hair growth and prolongs the duration of anagen phase, but the exact mechanism of these effects has not been known. Recently, it was reported that testosterone and dihydrotestosterone inhibited proliferation and induced apoptosis in dermal papilla cell and this might be another pathomechanism of androgenetic alopecia. In this study we investigate whether minoxidil promotes proliferation and inhibits apoptosis in cultured human dermal papilla cell. We used MTT assay to evaluate the influence of minoxidil on proliferative activity of dermal papilla cells at 0, 10-8, 10-7, and 10-6 M after 5 days, and also estimated the phosphorylation of extracelluar signalregulated kinase (ERK) by immunoblotting at 0, 10-7, and 10-6 M after 1, 24, and 48 hours. To evaluate the influence of minoxidil on apoptosis, the expression of bcl-2 and bax was detected by immunoblotting at 0, 10-7, and 10-6 M after 24 and 48 hours. In MTT assay proliferative activity of DPC was increased as a concentration-dependent manner and phosphorylation of ERK was also increased with minoxidil, which shows that the proliferative effect of minoxidil is induced by phosphorylation of ERK. The expression of bcl-2 was increased and the expression of bax was decreased with minoxidil after 24 hours, which shows antiapoptotic effect of minoxidil occurs through bcl-2/bax pathway. This study shows that minoxidil has proliferative and antiapoptotic effects on dermal papilla cells, and this may be one of the mechanism by which minoxidil acts on hair growth.