[Bimatoprost promotes hair growth of reconstructed hair follicles in mice through activation of the Wnt/β-catenin signaling pathway].

Objective: To investigate effect of Bimatoprost (BimP) on growth of reconstructed hair follicles in recipient nude mice. Methods: Primary epidermal and dermal cells were isolated from newborn C57BL/6J mice (1-day-old) skins, and the reconstructed hair follicles was implanted in the dorsal skin of Balb/c-nu nude mice using a silicon chamber protocol, then, the 18 nude mice were randomly divided into control group, BimP group and minoxidil group, with 6 mice in each group. After 2 weeks, topical treatment was applied to the grafted area of the nude mice by 2% minoxidil 100 μl, 0.03% BimP 100 μl and saline 100 μl, respectively, once daily for 2 weeks. At day 14 after treatment, the mice were euthanized to measure the length of dorsal hair, and the number and hair cycle of the reconstructed follicles was observed histologically. The total mRNA and proteins expression of Wnt3a, LEF1, β-catenin and Frizzled7 were determined by qPCR and Western Blotting. The distribution and expression of β-catenin in the reconstructed follicles was detected by immunofluorescence staining. Results: As compared to the control group, the BimP group had thicker and longer hair [(0.57±0.07) vs (0.36±0.05) cm, P<0.01], no significant difference was seen between the BimP and minoxidil group. The mRNA expression levels of Wnt3a (2.73±0.17 vs 1.00±0.14, P<0.01)、LEF1(1.71±0.12 vs 1.00±0.19, P<0.01)、β-catenin (2.37±0.21vs 1.00±0.11, P<0.01) and Frizzled7 (2.62±0.15vs 1.00±0.18, P<0.01) were significantly increased in BimP group compared with the control group. Western Blotting showed the same results, the protein expression levels of Wnt3a (1.44±0.21vs 1.00±0.13, P<0.05)、LEF1 (1.36±0.15 vs 1.00±0.09, P<0.05)、β-catenin (1.60±0.13 vs 1.00±0.16, P<0.01) and Frizzled7 (1.52±0.15 vs 1.00±0.21, P<0.05) in BimP group were higher than those in control group, and the difference was statistically significant. Immunofluorescence staining showed that β-catenin was strongly expressed in hair bulb cells and sebaceous gland cells of reconstructed hair follicles in BimP group and minoxidil group, whereas barely seen in the control group. Conclusion: BimP directly promotes growth of reconstructed hair follicles in mice by activating canonical Wnt/β-catenin signaling pathway.