ABSTRACT
Objective To investigate expression 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 expression 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 expression 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 expressions were seen in the cell nucleus. Lef1 was expressed specifically in hair germs and hair matrix, and its expression began to decrease on day 28. In addition, Ki67 expression 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.
ABSTRACT
With the development of medical education,the traditional cell biology teaching modes and methods need constant adjustment to adapt to the current teaching.In view of the present high-speed development of cell biology,we seriously picked some representative themes to carry out thematic teaching.Students were encouraged to read some references about the corresponding content and thought primarily before the class.After the lesson,the teacher guided students to discuss and find the answers to the questions they asked before.Participation in class discussion and homework completion accounted for 10％ of the final assessment results.The thematic teaching helped to optimize classical teaching contents and frontier progress.This teaching mode not only stimulated learning interest but also fully exercised learning ability.
ABSTRACT
BACKGROUND: Signal transducer and activator of transcription 3 (STAT3) protein is widely expressed in cells and tissues of different type and. It is the important component of signal transduction and transcription chain that participates in the regulation of various physiological functions of cells like proliferation and differentiation. However, there is no literature reported regarding if there is STAT3 expression and whether it participates in embryo liver development both at home and abroad.OBJECTIVE: To explore the effects and mechanism of STAT3 signal transduction route on development of embryo liver by. Studying the expression of STAT3 protein during embryo liver development in mice.DESIGN: Randomized controlled study based on STAT3 protein.SETTING: Department of histology and embryology in a military medical university of Chinese PLA.MATERIALS: The study was completed in the Department of Histology and Embryology, Third Military Medical University of Chinese PLA during January to June 2004. Kunming mice were provided by Animal Centre of Third Military Medical University of Chinese PLA. Ten male mice and 20 female mice with body mass during 25 to 30 grams were randomly chosen.METHODS: Serial frozen sections of mouse embryo was performed in the 13.5 days ( n = 8), 14.5 days ( n = 9) and 15.5 days ( n = 7) after mating respectively. One of the every 2 slices was used as negative control by replacing first antibody of STAT3 with 0. 01 mol/L PBS. Immunochemical technique and immunofluorescence method were used to display the expression of STAT3 protein in embryo liver development in mice.MAIN OUTCOME MEASURES: Expression of STAT3 protein in serial frozen sections of mouse embryo.RESULTS: There was strong expression of STAT3 protein in liver cells in E13.5 days mouse embryo while the expression was decreased in E14.5 days and E15.5 days mouse embryos.CONCLUSION: STAT3 protein has participated in the development of embryo liver. The expression of STAT3 in liver development can be used to explain the mechanism of liver regeneration and provide experimental data for organ repair.