[Three-dimensional culture of plucked human hair follicles inside the collagen gel matrix].

Plucked human hair follicles were cultured in collagen gel matrix. Epithelial cells, possibly outer root sheath keratinocytes, appeared from the outer root sheath 4 to 5 days after culturing and continually grew into the gel to form spike-like structures for next 3 weeks. The number and size of the spikes differed in each follicle. Autoradiographically, many DNA-synthesizing cells were seen at the outer cell layer in the enlarged outer root sheath and at the edges in the newly formed spike-like structures. The culture method described here appears to be suitable to study the three-dimensional growth, morphogenesis and differentiation of the outer root sheath cells in vitro.