Effect of Coapplication of Capsaicin and Minoxidil on the Murine Hair Growth
Won-Soo Lee, Hyung Jin Ahn, Young Hee Kim Department of Dermatology. Yonsei University Wonju College of Medicine, Wonju. Korea
Capsaicin induces the release of substance P(SP) which is believed to play an important role in murine hair growth and cycle. Minoxidil, the only approved topical hair drug having direct hair growth effect, has therapeutic limitation because it stimulates mainly vellus hair regrowth, not thick coarse terminal hairs. So, we hypothesize that combined use of capsaicin and minoxidil may exert positive effects in terms of hair growth than minoxidil alone. We evaluated the effects of coapplication of capsaicin and minoxidil on the hair growth and cycle, compared with application of capsaicin or minoxidil alone. We induced the anagen phase of the hair of back skin of ICR mice by depilation. We devied the mice into 4 groups, i.e., control group, capsaicin group, minoxidil group, and coapplied group. And then, we examined the hair growth macroscopically, and the percentage of the area of hair regrowth by image analysis using phototrichogram at the 0, the 5th, 10th, 15th, 20th, 25th, and 30th day. Also we examined the morphologic changes of hair follicles and subcutis, and the number of mast cells by microscopy, and[methyl-3H] thymidine uptake by scintillation counter. In this study, we observed that capsaicin can not only induce the anagen phase quickly, but also sustain constant effect on the linear hair growth. Minoxidil also induced the anagen phase fast, and prolong the anagen phase of the hair cycle. Therefore, it is concluded that the coapplication of capsaicin and minoxidil can grow hair quickly and steadily.
