氟尿嘧啶引起大鼠气管损伤及修复过程的观察及解析

目的 进行气管干细胞的定位研究。方法 使用氟尿嘧啶(5-FU)造成大鼠离体气管环的严重损伤,采用光镜、电镜及免疫组织化学链霉素抗生物素蛋白-过氧化物酶(SP)法检测增殖细胞核抗原(PCNA)动态观察气管黏膜的修复过程。结果 5-FU作用12h后,气管上皮脱落,可见少量间隔分布的类似裸核的细胞呈钉状位于基底膜上。去除5-FU 6h后,由扁平上皮覆盖;电镜下可见这些细胞缺乏分化;可见多个PCNA核染色阳性的细胞与1个阴性细胞(G0期细胞)的比例间隔分布;9h后,电镜下可见向纤毛细胞及黏液细胞分化;48h后,气管环全部由假复层纤毛柱状上皮细胞覆盖。结论 5-FU特异性地使进入细胞周期中的细胞变性坏死,而对G0期的细胞没有作用,残留于基底膜上的裸核样的G0期细胞增殖分化,再生出小黏液颗粒细胞和纤毛细胞进而修复损伤的气管环,证明气管干细胞位于气管上皮基底膜上的G0期细胞中。

Study of tracheal regeneration after injury induced by 5-fluorouracil in rats

Objective Localization of tracheal stem cells in rat trachea. Methods Extracorporeal tracheal injury (Wistar rats) was induced by 5-FU. The process of regeneration was observed and analyzed by light microscopy, electron microscopy, and immunohistochemistry. Results Twelve hours after treatment with 5-FU, the tracheal epithelium shed and cells with naked nuclei were seen located sparsely on the basement membrane. Six hours after removal of 5-FU, the tracheal rings were covered with flattened epithelium. These cells were poorly differentiated under electron microscopy. Immunohistochemistry showed few proliferating cell nuclear antigen ( PCNA) -negative cells sparsely scattered among PCNA-positive cells on the basement membrane. Nine hours later, electron microscopy found that these cells differentiated into mucous cells and ciliated cells. Forty-eight hours later, the tracheal rings were entirely covered by pseudostratified ciliated columnar epithelium. Conclusions A small number of G0 cells with naked nuclei are located sparsely on the basement membrane of the trachea. Tracheal epithelium regenerates by proliferation and differentiation of these cells. It is likely that some of these G0 cells on the tracheal basement membrane represent tracheal stem cells.