Abstract:

Objective To investigate the expression of angiogenin in human hair follicle and evaluate its effect on hair growth. Methods Intact anagen hair follicles were isolated from human occipital scalp obtained from brain surgery. Some isolated human hair follicles were directly subjected to RT-PCR and immunohistochemical method for the detection of the mRNA expression and protein distribution of angiogenin in, respectively; some were cultured and incubated with angiogenin （0-200 ng/mL）, and the measurement of hair follicle length was performed before and after 6-day culture. Human dermal papilla cells were isolated from the remaining hair follicles, cultured, and treated with angiogenin ranging from 0 to 200 ng/mL for 48 hours, then, MTT assay was used to detect the cell proliferation, and flow cytometry to analyze the cell cycle. Results RT-PCR showed the mRNA expression of angiogenin in human hair follicles, and angiogenin protein was observed with immunohistochemistry at the hair papilla and dermal sheath. The angiogenin （25-200 ng/mL） stimulated the growth of human hair follicles in a dose-dependent manner in vitro （P < 0.05）. Also, as flow cytometry revealed, the treatment with 12.5-200 ng/mL of angiogenin significantly promoted the proliferation of human dermal papilla cells （P < 0.05）, and increased the percentage of cells in S phase as well as cell proliferation index （both P < 0.05）. Conclusion Angiogenin may be a novel stimulus for hair growth.

Key words: Angiogenin;Hair follicle;Dermal papilla cell;angiogenesis