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目的探讨大鼠气管上皮损伤后,气管干细胞增殖分化过程中Shh信号通路的动态变化。方法大鼠麻醉后,暴露气管,于平胸骨上缘处离断,与肺相连一端行气管插管维持呼吸,近端应用5-氟尿嘧啶(5-FU)诱发气管上皮损伤,动态观察修复过程;同时在观察的各个时间点取气管上皮标本通过RT-PCR检测Shh的表达情况。结果5-FU作用30min后大鼠气管上皮细胞绝大部分脱落,仅残留少量裸核样G0期细胞位于基底膜上,之后这些细胞数目逐渐增多,逐渐经过扁平、立方形态,向纤毛细胞、粘液细胞、基底细胞等分化,于去除5-FU后48h基本恢复假复层纤毛柱状上皮;正常组织及5-FU作用30min时的气管上皮均无Shh表达,去除5-FU恢复3h后可见Shh轻度表达,于恢复12h表达达高峰,之后表达减弱,48h时Shh表达已极微弱。结论Shh参与了气管干细胞的增殖分化过程。
Objective To investigate the dynamic changes of Shh signaling pathway during tracheal-derived stem cell proliferation and differentiation after tracheal epithelial injury in rats. Methods After anesthesia, the trachea was exposed, and the superior trachea was severed at the upper edge of the sternum. One end of the trachea was connected with the lung to maintain the respiration. The tracheal epithelial injury was induced by 5-fluorouracil (5-FU) At the same time, tracheal epithelial specimens were taken at different time points to detect Shh expression by RT-PCR. Results After tracheal instillation of 5-FU for 30 min, most of the tracheal epithelial cells were detached. Only a small amount of naked nucleated G0 phase cells were located on the basement membrane. After that, the number of these cells gradually increased and gradually passed through the flat and cuboidal morphology. Cells and basal cells were differentiated, and the pseudostratified ciliated columnar epithelium was recovered 48h after removing 5-FU. No expression of Shh was observed in tracheal epithelium of normal tissue and 5-FU for 30min, and Shh was recovered after 5h removal of 5-FU The expression reached a peak at 12h after recovery, and then decreased. The expression of Shh at 48h was very weak. Conclusion Shh is involved in the proliferation and differentiation of tracheal stem cells.