Hair growth in human split-thickness skin grafts transplanted onto nude rats: the role of cyclosporin.
To date, there have been no descriptions of hair growth following transplantation of human split-thickness skin grafts (HSTSG) to congenitally athymic (nude) mice or rats. Recently, we noted hair growth in HSTSG from scalp skin (HSTSG-SS) transplanted onto rats treated with ciclosporin (CS). By definition, HSTSG-SS of 0.4 mm had all the anagen hairs cut from the papillae. Two months after engraftment, there was histological evidence of the formation of new papillae. Density of hair correlated with thickness of HSTSG, i.e. there were more hairs/square centimeter in HSTSG-SS of 1 mm thickness than in those of 0.4 mm thickness. New hairs appeared on an average of 1 cm2/week in HSTSG-SS that were 1 mm thick; by 10 weeks, the mean density was 7.9 hairs/cm2. In the thinner grafts, the density was 3.5 hairs/cm2 (p less than 0.025). The rate of growth in the thicker grafts ranged from 0 to 0.25 mm/day, with an average of 0.1 mm/day. At 10 weeks after grafting, the hairs had a mean length of 4.4 mm in the thicker and 1.7 mm in the thinner grafts (p less than 0.001). The average diameter of the hair shafts was 0.05 mm at the various times tested. These observations identify a previously unrecognized process of hair growth and present an in vivo model to study human hair growth process, including the role of CS in hair growth.
Gilhar
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Laboratory for Skin Research, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa.
Etzioni
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Krueger
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D000818:Animals; D001345:Autoradiography; D001379:Azathioprine / Q000008:administration & dosage; D001706:Biopsy; D003524:Cyclosporins / Q000008:administration & dosage / Q000494:pharmacology*; D006197:Hair / Q000254:growth & development*; D006854:Hydrocortisone / Q000008:administration & dosage; D007274:Injections, Intraperitoneal; D007279:Injections, Subcutaneous; D051381:Rats; D011923:Rats, Nude; D016038:Skin Transplantation / Q000379:methods / Q000473:pathology
D003524:Cyclosporins; D001379:Azathioprine; D006854:Hydrocortisone