IL-27通过STAT3信号通路改善脂多糖诱导的小鼠急性肺炎

目的：探讨IL-27通过调控STAT3信号通路在脂多糖（LPS）诱导的小鼠急性肺炎中的作用。方法：32只雄性小鼠随机分为正常对照组、LPS组、LPS+IL-27组、LPS+IL-27抗体组，每组8只。麻醉处死后取小鼠肺脏，HE染色观察各组小鼠肺组织损伤情况；qRT-PCR检测各组小鼠肺组织及血清中STAT3、SOCS3的mRNA表达水平；Western blot检测各组小鼠肺组织中STAT3、p-STAT3、SOCS3的蛋白表达水平；采用ELISA法分别检测肺组织匀浆及血清中TNF-α、IL-1β、IL-10、TGF-β1的表达水平。免疫组织化学及Western blot检测TNF-α、IL-1β在肺组织中的蛋白表达。结果：HE染色结果发现，正常对照组，LPS组和LPS+IL-27抗体组肺泡结构被破坏，肺泡壁弥漫性增厚，有明显的炎性细胞浸润；LPS+IL-27组病理改变较LPS组明显减轻，炎性细胞浸润减少。与正常对照组比，LPS组和LPS+IL-27抗体组小鼠肺组织STAT3、p-STAT3蛋白表达水平显著升高（P＜0.05）；LPS+IL-27组较LPS组和LPS+IL-27抗体组显著降低（P＜0.05），LPS+IL-27组SOCS3表达水平显著高于LPS+IL-27抗体组（P＜0.05）。各组小鼠肺组织及血清TNF-α、IL-1β表达水平较正常对照组均显著升高（P＜0.05）；LPS+IL-27组TNF-α、IL-1β表达水平较LPS组和LPS+IL-27抗体组显著降低（P＜0.05）；LPS组和LPS+IL-27抗体组IL-10表达水平均显著高于正常对照组（P＜0.05）；LPS+IL-27组IL-10、TGF-β1的表达水平均显著高于LPS+IL-27抗体组（P＜0.05）。免疫组织化学结果显示，与正常对照组比，LPS组和LPS+IL-27抗体组TNF-α阳性表达主要表达在细胞浆中，IL-1β阳性表达主要表达与细胞膜与细胞浆中，Western blot结果发现TNF-α、IL-1β在肺组织中均呈高表达（P＜0.05）；LPS+IL-27组TNF-α、IL-1β的表达水平较LPS组和LPS+IL-27抗体组显著降低（P＜0.05）。结论：外源性IL-27可能通过抑制STAT3信号通路相关蛋白磷酸化水平改善LPS诱导的小鼠急性肺炎。

IL-27 regulates LPS-induced acute pneumonia in mice through STAT3 signaling pathway

Objective: To investigate the role of IL-27 in lipopolysaccharide (LPS)-induced acute pneumonia in mice by regulating STAT3 signaling pathway. Methods: A total of 32 male mice were randomly divided into normal control group, LPS group, LPS+IL-27 group and LPS+IL-27 antibody group, with 8 mice in each group. After anaesthesia, the lungs of mice were taken and staining was used to observe the lung injury of mice in each group by HE. The mRNA expression levels of STAT3 and SOCS3 in lung tissue and serum of mice in each group were detected by qRT-PCR. Western blot method was used to detect the protein expression levels of STAT3, p-STAT3 and SOCS3 in lung tissue of mice in each group. The expression levels of TNF-α, IL-1β, IL-10 and TGF-β1 in lung homogenate and serum were detected by ELISA. Results: HE staining showed that in the normal control group, LPS group and LPS+IL-27 antibody group, the alveolar structure was destroyed, the alveolar wall was diffusely thickened, and there was obvious inflammatory cell infiltration. The pathological changes and inflammatory cell infiltration of LPS+IL-27 group were less than those of LPS group. Compared with the normal control group, the expression levels of STAT3 and p-STAT3 protein in lung tissue of mice in LPS group and LPS+IL-27 antibody group was significantly increased (P<0.05); the expression level of SOCS3 in LPS+IL-27 group was significantly higher than in LPS+IL-27 antibody group (P<0.05). The expression levels of TNF-α and IL-1β in lung tissue and serum of mice in each group were significantly higher than those in the normal control group (P<0.05). The expression levels of TNF-α and IL-1β in LPS+IL-27 group were significantly lower than those in LPS group and LPS+IL-27 antibody group (P<0.05). The level of IL-10 expression in LPS group and LPS+IL-27 antibody group was significantly higher than that in normal control group (P<0.05). The expression levels of IL-10 and TGF-β1 in LPS+IL-27 group was significantly higher than those in LPS+IL-27 antibody group (P<0.05). The results of immunohistochemistry showed that compared with the normal control group, TNF-α was mainly expressed in the cytoplasm of LPS group and LPS+IL-27 antibody group, while IL-1β was mainly expressed in the membrane and cytoplasm. Western blot showed that TNF-α and IL-1β were were highly expressed in lung tissue (P<0.05); the expression level of TNF-α and IL-1β in LPS+IL-27 group was significantly lower than that in LPS group and LPS+IL-27 antibody group (P<0.05). Conclusion: Exogenous IL-27 may improve LPS-induced acute pneumonia in mice by inhibiting the phosphorylation of STAT3 signaling pathway related proteins.