探讨急性呼吸窘迫综合征（ARDS）小鼠肺组织中肺内源性干细胞的表达水平。

10只C57BL/6小鼠分成两组：实验组和对照组，实验组通过气管内注射脂多糖（LPS）构建小鼠ARDS模型，采用气管内注射PBS作为对照组；采用胶原酶、热消化法消化小鼠肺组织获取小鼠肺单细胞悬液；双重免疫荧光染色方法鉴定小鼠肺组织中sca-1⁺CD31^-CD45^-细胞；流式细胞术对肺sca-1⁺CD31^-CD45^-细胞进行分选。采用方差分析及独立t检验进行统计学分析。

通过气管内注入LPS成功制作小鼠急性ARDS模型；5只小鼠的全肺组织制备单细胞悬液总数目达5×10⁷个/ml，活细胞百分比为98﹪；肺内源性干细胞包括Ⅱ型肺泡上皮细胞、clara细胞以及支气管肺泡干细胞等，通过肺组织双重免疫荧光染色，验证小鼠肺组织Ⅱ型肺泡上皮细胞、clara细胞以及支气管肺泡干细胞；对照组及实验组各样本肺内源性干细胞数目占单细胞悬液细胞数比例呈正态分布，且实验组肺内源性干细胞数目水平（10.73±10.65）﹪较对照组水平（12.23±0.73）﹪降低（t = -3.405，P < 0.01）。

ARDS时，小鼠肺内源性干细胞（sca-1⁺CD31^-CD45^-）水平降低，减少的肺内源性干细胞具体去向尚不明确，其有可能参与机体急性炎症过程中气道上皮细胞的修复、再生过程。

To study the expression level of lung sca-1⁺ CD31^- CD45^- cells in lung tissue of mice with acute respiratory distress syndrome (ARDS) .

10 C57BL/6 mice were divided into experimental group and the control group. The experimental group was established by intratracheal injection of lipopolysaccharide (LPS) to construct the mouse ARDS model, and intratracheal injection of PBS was used as the control group. Lung tissue of ARDS mouse model was treated with collagenase and heat digestion to obtain lung single cell suspension. Dual immunofluorescence staining was adopted to identify lung endogenous stem cells. Lung sca-1⁺ CD31^-CD45^- cells were sort by flow cytometry.

The ARDS model was successfully prepared by intratracheal injection of lipopolysaccharide; the total number of single cell suspensions prepared by whole lung tissue of 5 mice was 5×10⁷/ml, and the percentage of viable cells was 98﹪; Lung Endogenous stem cells include type Ⅱ alveolar epithelial cells, clara cells, and bronchoalveolar stem cells. The lung tissue type Ⅱ alveolar epithelial cells, clara cells, and bronchoalveolar stem cells were verified by double immunofluorescence staining of lung tissues. The number of lung endogenous stem cells in the control group and the experimental group accounted for a normal distribution of the number of single cell suspension cells, and the number of lung endogenous stem cells in the experimental group (10.73±10.65) ﹪ was significantly lower than that in the control group (12.23±0.73) ﹪ (t?= -3.405, P < 0.01) .

The proportion of lung sca-1⁺ CD31^-CD45^- cells in lung tissue of ARDS mice is significantly lower than that of the control group. It is not clear that the specific fate of these lung endogenous stem cells is reduced. It may participate in the repair and regeneration process of airway epithelial cells during acute inflammation in the body.