粪菌移植通过调节TLR4/NF-κB信号通路改善内毒素性急性肺损伤

Fecal microbiota transplantation improves endotoxin-induced acute lung injury by regulating TLR4/NF-κB signaling pathway

目的:探讨粪菌移植(FMT)对内毒素性急性肺损伤(ALI)大鼠TLR4/NF-κB信号通路的影响。方法:选取成年SD大鼠15只,随机均分为对照组(NS组)、模型组(LPS组)和干预组(FMT组)。利用腹腔注射LPS构建ALI模型;造模完成后,FMT组给予粪菌液灌胃,NS组和LPS组予以等量的氯化钠溶液灌胃。干预结束24 h后观察肺组织病理改变,检测肺湿/干重(W/D)比值,动脉血PaO_(2),ELISA检测血清中IL-10的含量,Western blot测定肺组织中TLR4、p-NF-κB p65、NF-κB p65蛋白的表达量,免疫组化检测肺泡上皮细胞中的MyD88表达,收集大鼠粪便样品进行高通量测序。结果:与NS组比较,LPS组肺组织肺泡水肿明显,炎症细胞浸润,肺泡间隔增宽,PaO_(2)和血清中IL-10的含量降低(P<0.05);肺组织中TLR4、p-NF-κB p65、MyD88表达明显上调(P<0.05);肠道菌群结构改变。与LPS组比较,FMT组损伤的肺组织恢复明显,肺W/D比值下降,血清PaO_(2)及IL-10含量上升(P<0.05)。TLR4、MyD88、p-NF-κB p65的表达水平下降(P<0.05)。肠道菌群结构接近正常对照组。结论:FMT可能通过作用于TLR4/MyD88/NF-κB通路抑制肺组织免疫炎症反应,进而改善LPS诱导的大鼠ALI。

Objective:To investigate the effect of fecal microbiota transplantation on TLR4/NF-κB signaling pathway in rats with endotoxin-induced acute lung injury(ALI).Methods:Fifteen adult healthy male SD rats were divided into control group(NS group),model group(LPS group)and intervention group(FMT group)by random number table method.The ALI model was reproduced by intraperitoneal injection of LPS.After the completion of modeling,FMT group was gavage with fecal liquid.While NS group and LPS group were given the same amount of normal saline.Lung pathology was observed 24 h after the intervention,lung wet/dry weight(W/D)ratio was detected,arterial blood PaO_(2) was detected,serum IL-10 was detected by ELISA.TLR4,p-NF-κB p65,NF-κB p65 protein expression in lung tissue was determined by Western blot,MyD88 expression in alveolar epithelial cells was detected by immunohistochemistry,and rat fecal stool samples were collected for high-throughput sequencing.Results:Compared with NS group,LPS group showed obvious alveolar edema,inflammatory cell infiltration,widened alveolar septa,and decreased PaO_(2) and serum IL-10(P<0.05);TLR4,p-NF-κB p65 and MyD88 were significantly up-regulated in lung tissue(P<0.05);structural changes of intestinal flora.Compared with the LPS group,the lung tissue of FMT group recovered significantly,the lung W/D ratio decreased,and the serum PaO_(2) and IL-10 levels were increased(P<0.05);levels of TLR4,MyD88 and p-NF-κB p65 were decreased(P<0.05).The structure of intestinal flora was close to that of the normal control group.Conclusion:FMT may improve LPS-induced ALI in rats by acting on the TLR4/MyD88/NF-κB pathway to inhibit the immune inflammatory response in lung tissue.