Abstract:

Xing Yizhan, Guo Haiying, Ma Xiaogen, Li Yuhong Department of Cell Biology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China Corresponding author: Li Yuhong, Email: liyuhongtmmu@hotmail.com 【Abstract】 Objective To investigate characteristics in regenerating hair follicles induced by Wnt10b, and to explore mechanisms underlying Wnt10b-induced regeneration of hair follicles. Methods Both adenovirus containing the Wnt10b gene （AdWnt10b） and that containing the green fluorescent protein-encoding gene （AdGFP） were amplified in HEK-293 cells and purified by caesium chloride density gradient centrifugation. A total of 36 C57BL/6J mice were randomly and equally divided into the AdWnt10b group and AdGFP group to be intracutaneously injected with AdWnt10b and AdGFP on the back respectively. Three mice were sacrificed on day 2.5, 5, 7, 9, 14 and 28 after the injection separately, and skin samples were resected from the injected sites subsequently. Hematoxylin and eosin （HE） staining and immunohistochemical staining were performed to observe hair follicle structure, analyze characteristics of the Wnt signaling pathway, and to estimate proliferative activity of regenerating hair follicles induced by Wnt10b. Results As HE staining showed, new hair follicles appeared as early as day 5 after the injection, then grew normally, and entered into catagen phase on day 28 in the AdWnt10b group. Immunohistochemical staining showed that AE15 was observed in new hair follicles as early as day 5 after the injection in the AdWnt10b group, then increased along with the growth of hair follicles, but decreased on day 28. On day 5 after AdWnt10b injection, both β-catenin and Lef1 s were seen in the cell nucleus. Lef1 was expressed specifically in hair germs and hair matrix, and its began to decrease on day 28. In addition, Ki67 was observed in the epidermis and outer root sheath of hair follicles as early as day 2.5 after the injection, in the bulge region of hair follicles on day 2.5, 7, 9 and 14, and in hair matrix cells as early as day 7. Conclusion Wnt10b could induce regeneration of hair follicles with normal structure, likely by activating the canonical Wnt signaling pathway in hair follicle stem cells and their daughter cells.