Effects of TNF-${\alpha}$ and Minoxidil on Human Hair Growth in Vitro

Background : The factors that regulate hair follicle growth are still poorly understood. In vitro models may be useful in elucidating some aspects of hair follicle biology. TNF- is potent inhibitor of hair follicle growth. TNF- induces the formation of a club-like hair follicle, similar to catagen morphology of the hair bulb. Minoxidil induces generalized hypertrichosis when administered systemically, or localized hair regrowth when applied topically to sites of alopecia. Objective : The purpose of this study is to investigate the effect of TNF- and minoxidil on human hair growth using in vitro model. Methods : Healthy human hair follicles without any visible damage were collected, they were cultured in Williams E medium with several combinations of supplements and TNF- and/or minoxidil were added to the media. The results were evaluated by measuring linear hair fiber growth and hair follicle morphology on light microsocopy and by measuring radioisotope uptake of 〔methyl-3H〕 thymidine of hair follicle. Results : The following results were obtained from this study. 1. TNF- have inhibitory effect on the rate of linear hair growth in cultured hair follicles. 2. Minoxidil has no stimulatory effect on the rate of linear hair growth and no protective effect on the TNF- induced growth inhibition in cultured hair follicles. Conclusion : TNF- has growth-inhibitory effect and minoxidil has no protective effect on the TNF- induced hair change.