Abstract
BACKGROUND: The human placenta (HP) is a complex organ used to alleviate tiredness and promote wound healing. Previous research showed the hair growth-promoting effect of HP. However, no reports have addressed the effects of HP on hair regrowth in chemotherapy-induced alopecia. In this study, we investigated the effects of HP on the apoptosis and proliferation of hair follicles in chemotherapy-induced alopecia. METHODS: Male C57BL/6 mice in telogen were depilated to enter anagen. After 9 days, dystrophic catagen was induced by the intraperitoneal injection of 150 mg/kg cyclophosphamide. During 9 to 16 days, 0.1 and 1 mg/mL HP were topically applied to depilated dorsal skin. RESULTS: Dystrophic hair follicles by cyclophosphamide were recovered by HP treatment. New hair shafts containing hair fibers appeared to be straight after HP treatment. Immunohistological staining revealed a significant increase of Ki67-positive cells in hair follicles treated with 1 mg/mL HP. Topical HP treatment increased the ratio of Bcl-2/Bax, while it attenuated the expression of pro-apoptotic Bax, p53, and cytochrome c with caspase-9 and -3. In addition, the expression of KGF and the phosphorylation of AKT were upregulated by HP treatment. CONCLUSION: These results suggest that HP treatment induced hair growth by inhibiting apoptosis and promoting the proliferation of hair follicles. HP may be useful for treating chemotherapy-induced alopecia.