Sonic hedgehog信号通路相关分子表达上调对脂多糖致小鼠急性肺损伤的保护作用

Up-regulation of molecules associated with Sonic hedgehog signaling pathway plays a protective role in mouse acute lung injury induced by lipopolysaccharide

目的探讨Sonic hedgehog(SHH)信号通路在脂多糖(LPS)诱导的急性肺损伤(ALI)中的表达变化及意义。方法实验动物随机分为对照组、5 mg/kg LPS处理组、50 mg/kg环巴胺处理组。HE染色观察肺组织病理改变,测定肺湿干质量比值(W/D),反转录PCR检测肺组织肿瘤坏死因子α(TNF-α)及SHH、Patched(PTC)及下游转录因子GLI1的mRNA表达,Western blot法检测肺组织SHH和GLI1的蛋白表达。结果 LPS处理组肺组织病理损伤评分、W/D、TNF-αmRNA表达水平明显高于对照组。LPS处理组SHH、PTC、GLI1的mRNA表达水平,在6 h与对照组相比,无明显差异,LPS处理12、24 h时表达水平明显高于对照组,与时间呈正相关。与对照组相比,LPS处理组6、12、24 h的SHH、GLI1蛋白表达水平均明显升高,且与时间呈正相关。环巴胺处理后,SHH、PTC、GLI1的mRNA表达及SHH、GLI1的蛋白表达水平均降低,同时肺组织病理损伤评分、W/D及TNF-αmRNA表达均高于LPS处理组。结论 LPS所致ALI的发展过程中存在SHH信号通路的激活,且SHH信号通路相关分子表达上调,可减轻肺损伤参与肺组织损伤后修复。

Objective To explore the expression changes and significance of Sonic hedgehog （SHH） signaling pathway in lipopolysaccharide （LPS）-induced acute lung injury （ALl）. Methods The experimental animals were randomly divided into control group, LPS-treated group （LPS 5 mg/kg ） and cyclopamine-treated group （cyclopamine 50 mg/kg ）. The pathological changes of lung tissues were observed with HE staining, and the lung wet to dry mass ratio （W/D） was measured. Real-time quantitative PCR （RT-PCR） was used to detect the mRNA expressions of tumor necrosis factor α （TNF-α）, SHH, Patched （PTC） and downstream transcription factor GLll in lung tissues, and Western blotting was adopted to determine the protein levels of SHH and GLI1 in lung tissues. Results Pathological injury score of lung tissues, W/D and mRNA level of TNF-α were significantly higher in the LPS-treated group than in the control group. Compared with the control group, the mRNA levels of SHH, PTC and GLI1 in the LPS-treated group were not significantly different at 6 hours and were remarkably higher at 12 and 24 hours, with a positive correlation with the time. Protein expression levels of SHH and GLII at 6, 12 and 24 hours in the LPS-treated group showed a more notable increase than those in the control group, and a positive correlation with the time was displayed. After cyclopamine intervention, the mRNA levels of SHH, PTC and GLII and the protein levels of SHH and GLI1 were all reduced, while pathological injury score of lung tissues, W/D and mRNA level of TNF-a were obviously higher than those in the LPS-treated group. Conclusion SHH signaling pathway was activated in the development process of LPS-induced ALl, and up-regulated expressions of SHH signaling pathway associated molecules could relieve lung injury and involve repair of the injured lung tissues.