[Role and mechanism of IL-6/STAT3/Th17 signaling pathway in the intervention of forsythia in acute lung injury of septic rats].

Objective: To investigate the mechanism of interleukin-6 (IL-6) /signal transducers and activators of transcriptional 3 (STAT3) /helper T cell 17 (Th17) signaling pathway in lung injury of rats with sepsis intervened by forsythia, with a view to provide experimental basis for the role and mechanism of forsythia in the treatment of sepsis. Methods: In July 2021, 30 healthy Wistar male rats were selected and randomly divided into sham operation group, model group and treatment group, with 10 rats in each group. The rat model of sepsis was established by cecal ligation and puncture. 2 h after recovery, the rats were given traditional Chinese medicine forsythia orally, twice a day at an interval of 12 h. The wet/dry mass ratio (W/D) of lung tissue was detected 24 h after surgery. The morphological changes of lung tissue were detected by HE staining. Flow cytometry was used to detect Th17 population in peripheral blood. The expression levels of IL-6 and interleukin-17A (IL-17A) in serum were determined by enzyme-linked immunosorbent assay. The mRNA expression levels of IL-17A and IL-6 in lung tissues were detected by reverse transcription-polymerase chain reaction. The expression levels of STAT3 and IL-17A in lung tissue were determined by Western blotting. Results: Compared with model group, the W/D of lung tissue in treatment group was decreased, and the difference was statistically significant (P<0.05). HE staining of lung tissue showed that compared with the model group, the degree of lung lesion and injury was reduced in the treatment group. Compared with sham operation group, the proportion of Th17 cells in CD4 lymphocytes in peripheral blood of rats in model group was significantly increased (P<0.05). Compared with model group, the proportion of Th17 cells in CD4 lymphocytes in peripheral blood of rats in treatment group was significantly decreased (P<0.05). Compared with sham operation group, peripheral blood serum IL-6 and IL-17 of rats in model group were significantly increased (P<0.05). Compared with model group, IL-6 and IL-17 in peripheral blood serum of rats in treatment group were decreased (P<0.05). Compared with sham operation group, the expressions of IL-17A and IL-6 mRNA in lung tissue of model group were significantly increased (P<0.05). Compared with model group, the expressions of IL-17A and IL-6 mRNA in lung tissue of rats in treatment group were significantly decreased (P<0.05). Compared with sham operation group, the protein expressions of STAT3 and IL-17A in lung tissue in model group were significantly increased (P<0.05). Compared with model group, the pritein expressions of STAT3 and IL-17A in lung tissue in treatment group were significantly decreased (P<0.05) . Conclusion: Forsythia plays a role in alleviating lung injury by down-regulating the expressions of the signaling pathway IL-6/STAT3/Th17, which providing a new target for the treatment of sepsis induced lung injury.目的： 探讨白细胞介素6（IL-6）/信号转导和转录激活子3（STAT3）/辅助性T细胞17（Th17）信号通路在连翘干预脓毒症大鼠肺损伤中的作用机制，以期为连翘治疗脓毒症的作用及机制提供实验依据。 方法： 于2021年7月，选择健康Wistar雄性大鼠30只，随机分为假手术组、模型组和治疗组，每组10只。采用盲肠结扎穿刺法建立脓毒症大鼠模型，大鼠苏醒后2 h经口灌胃中药连翘，间隔12 h，每日2次，以术后24 h为观察时间点，检测肺组织湿/干质量比（W/D）；HE染色检测肺组织的形态学变化；流式细胞仪检测外周血Th17群体；酶联免疫吸附法测定血清中IL-6和白细胞介素17（IL-17）的表达水平；逆转录-聚合酶链反应法检测肺组织IL-17A和IL-6 mRNA的表达水平；蛋白质免疫印迹法测定肺组织STAT3和IL-17A的表达水平。 结果： 与模型组比较，治疗组大鼠肺组织W/D下降，差异有统计学意义（P<0.05）。肺组织HE染色显示，与模型组比较，治疗组大鼠肺组织病变及损伤程度减轻。与假手术组比较，模型组大鼠外周血Th17细胞占CD4淋巴细胞比例明显升高（P<0.05）；与模型组比较，治疗组大鼠外周血Th17细胞占CD4淋巴细胞比例明显降低（P<0.05）。与假手术组比较，模型组大鼠外周血清中IL-6、IL-17表达均明显升高（P<0.05）；与模型组比较，治疗组大鼠外周血清中IL-6、IL-17表达均降低（P<0.05）。与假手术组比较，模型组大鼠肺组织IL-17A、IL-6 mRNA表达均明显升高（P<0.05）；与模型组比较，治疗组大鼠肺组织IL-17A、IL-6 mRNA表达均明显降低（P<0.05）。与假手术组比较，模型组大鼠肺组织STAT3、IL-17A蛋白表达均明显升高（P<0.05）；与模型组比较，治疗组大鼠肺组织STAT3、IL-17A蛋白表达均明显降低（P<0.05）。 结论： 连翘通过下调信号通路IL-6/STAT3/Th17的表达发挥作用，减轻肺损伤，为脓毒症致肺损伤的治疗提供新的靶点。.