衰老对小鼠肺干细胞修复能力的影响

Effect of aging on repair capability of lung stem cells

目的研究衰老对小鼠肺组织干细胞在生理状态和支气管上皮细胞(Clara细胞)损伤后修复能力的影响。方法通过流式细胞术对老龄和低龄组小鼠的肺组织干细胞比例进行分析,研究衰老对肺组织干细胞稳态维持的影响;通过免疫组化染色对肺组织病理切片进行分析,确立支气管上皮细胞(Clara细胞)损伤模型;通过流式细胞术、免疫组化染色、肺组织病理切片研究老龄和低龄组小鼠在支气管上皮细胞(Clara细胞)损伤后肺组织干细胞的损伤修复能力。结果老龄组肺组织干细胞比例(肺上皮干细胞/前体细胞,肺间质干细胞/前体细胞)在稳态维持的情况下较低龄组改变不显著;在肺支气管上皮细胞(Clara细胞)损伤后,老龄组小鼠支气管上皮出现较严重的细胞受损;在接下来的观察中发现,小鼠肺组织前体细胞/肺组织总细胞比例在老龄组显著下降,且增殖细胞在肺组织前体细胞和肺组织干细胞中的比例出现显著下降;同时,小鼠支气管上皮恢复程度在老龄组明显较差。结论在稳态维持的状态下,衰老对肺组织干细胞的比例没有影响。在支气管上皮细胞受到损伤后,肺组织干细胞占肺总细胞比例降低,修复与再生能力显著下降。可能为临床上衰老更易产生肺组织损伤及病变更严重的原因。

Objective To study the impact of aging on the capability of lung stem cell steady-state maintaining and bronchial epithelial cells regeneration and differentiation during the repair of lung epithelial cells after naphthalene induced bronchial epithelialium injury.Methods The proportion of lung stem cells in mice after naphthalene treatment was analyzed by immunohistochemistry and FACS.The repair efficiency of lung epithelial cell in young and old mice was examined by immunohistochemistry staining and FACS.Results The data suggested that aging didn ’ t change the proportion of lung stem cells （ including the distal lung epithelial stem cells/progenitor cells and lung mesenchymal stem cells/progenitor cells） under normal physiological conditions.After naphthalene injury, more serious injury and decreased repairing capacity was observed in old group.Lung progenitor cells /total lung cells decreased during the repair process of lung bronchial epithelialium （ clara cell） injury.The ratio of regenerated cell to lung progenitor and stem cells were also significantly decreased in old group.Conclusion The regenerated capability of lung stem cells after lung bronchial epithelialium injury decreased with aging.This might be the reason of more incidence of lung injury and worse therapeutic results in the elder in clinic.