LOCAL INJECTION OF HEPATOCYTE GROWTH-FACTOR SCATTER FACTOR (HGF SF) ALTERS CYCLIC GROWTH OF MURINE HAIR-FOLLICLES/

Hepatocyte growth factor/scatter factor (HGF/SF) has recently been sho wn to stimulate the hair follicle growth of mouse vibrissae in vivo. I n this study, we analyzed the effect of cutaneous injections of recomb inant human HGF/SF on hair follicle growth using mice in different hai r cycle stages, Five male newborn mice, five male mice in second anage n, and five male mice in second telogen were administered a dorsal int radermal injection of 1 mu g HGF/SF dissolved in 0.1% albumin-phosphat e-buffered saline once daily for five or seven consecutive days, and t hen sacrificed on days 7 or 10, Hair follicle growth was evaluated pho tometrically and histologically using three parameters: the skin color of the reverse side of the resected skin, the skin thickness, and the area occupied by hair follicle tissue, The HGF/SF injected skin of ne wborn mice had hair follicles that were histologically longer and larg er than those of the 0.1% albumin-phosphate-buffered saline injected s kin. Mice that had received HGF/SF injection in second anagen, retaine d anagen hair follicles after 10 d only at the injection site, suggest ing that HGF/SF delayed the transition from anagen to telogen. The HGF /SF injected skin of telogen mice had a significant increase in hair f ollicle tissue in the dermis, suggesting a mild anagen inducible activ ity by HGF/SF. Furthermore, precise measurements of the 20 hairs pluck ed from the HGF/SF injection sites revealed mild hair elongation in al l the aforementioned experiments. These results imply that HGF/SF acts as a paracrine factor that alters cyclic hair growth of mice.