抑制钙结合蛋白S100A4表达缓解小鼠脓毒血症相关肺损伤的研究

目的 探讨抑制钙结合蛋白S100A4表达在脓毒血症相关肺损伤中的意义及潜在的调控机制。方法 复制脓毒血症模型小鼠，部分加氯硝柳胺Niclosamide预处理，收集肺泡灌洗液和肺组织。BCA蛋白定量法检测小鼠肺泡灌洗液总蛋白浓度；酶联免疫吸附试验检测肺S100A4蛋白含量；苏木精-伊红染色评估小鼠肺部炎症；免疫组织化学检测肺S100A4蛋白和紧密连接蛋白Occludin表达情况，Western blotting检测潜在信号分子的表达。结果 与Con组比较，LPS组小鼠肺泡灌洗液总蛋白浓度升高（P <0.05），与Con组比较，肺S100A4水平差异无统计学意义（P >0.05）；免疫组织化学染色结果显示，肺支气管上皮细胞高表达S100A4，且LPS组S100A4表达较Con组升高（P <0.05），Occludin表达较Con组降低（P <0.05）；Western blotting结果显示，LPS组STAT3和MAPK3表达较Con组升高（P <0.05）。与LPS组比较，Niclosamide预处理可有效降低小鼠肺支气管上皮细胞S100A4表达（P <0.05），一定程度上恢复Occludin表达和下调STAT3、MAPK3表达。结论 Niclosamide可能通过STAT3、MAPK3信号下调S100A4和上调Occludin表达，进而缓解脓毒血症相关肺损伤。

Inhibition of calcium-binding protein S100A4 expression may alleviate sepsis-associated lung injury

Objective To explore the significance and potential regulatory mechanisms of inhibiting the expression of calcium-binding protein S100A4 in sepsis-related lung injury.Methods Sepsis mouse models were established, and some mice were pretreated with niclosamide. Bronchoalveolar lavage fluid and lung tissue were collected. The BCA protein quantification method was used to detect the total protein concentration in mouse bronchoalveolar lavage fluid. ELISA was used to measure lung S100A4 protein levels. Hematoxylin-eosin staining was performed to evaluate pulmonary inflammation. Immunohistochemistry was used to detect the expression of lung S100A4 protein and tight junction protein Occludin. Western blotting was performed to detect the expression of potential signaling molecules.Results Compared with the Con group, the total protein concentration in the bronchoalveolar lavage fluid of mice in the LPS group increased (P < 0.05). There was no statistically significant difference in lung S100A4 levels compared to the Con group (P > 0.05). Immunohistochemical staining showed that bronchial epithelial cells in the lungs of mice in the LPS group had high expression of S100A4, and S100A4 expression was higher in the LPS group than in the Con group (P < 0.05), while Occludin expression was lower in the LPS group than in the Con group (P < 0.05). Western blotting showed that the expression of STAT3 and MAPK3 in the LPS group was higher than that in the Con group (P < 0.05). Compared with the LPS group, niclosamide pretreatment effectively reduced the expression of S100A4 in bronchial epithelial cells of mice (P < 0.05), to some extent restored Occludin expression, and downregulated the expression of STAT3 and MAPK3.Conclusion Niclosamide may downregulate S100A4 and upregulate Occludin expression through the STAT3 and MAPK3 signaling pathways, thereby alleviating sepsis-related lung injury.