Liangxue Huoxue decoction protects against sepsis-induced acute lung injury by restoring gut microbiota and inhibiting inflammation and oxidative stress via the SIRT1/NF-κB/Nrf2 signaling pathway.

Liangxue Huoxue decoction(LXHX) is an effective empirical traditional Chinese medicine prescription,which has been clinically used for abdominal infectious disease for many years in Tianjin Nankai Hospital.Acute lung injury (ALI) is a severe inflammatory condition that causes lung inflammation and gut microbiota disruption. The aim of this study was to investigate the effects of LXHX on cecal ligation and puncture (CLP)-induced ALI and the related mechanisms. The principal components of LXHX were identified by high-performance liquid chromatography (HPLC).The effect of LXHX on gut microbiota was determined by 16S rRNA, while its anti-inflammatory, antioxidant, and anti-apoptotic effects were evaluated in lung tissue.16S rRNA sequence analysis showed that LXHX could partially restore the composition and diversity of intestinal flora.LXHX increased the Chao,Shannon,and Simpson index of the fecal microbiota,compared to CLP group. At the class and order level,the abundance of Gammaproteobacteria were increased in CLP group, while the abundance of Bacteroidia decreased. After LXHX treatment the abundance of Gammaproteobacteria decreased,while the abundance of Bacteroides increased.In addition, LXHX can alleviate CLP-induced pulmonary inflammation and edema as evidenced by reduced lung tissue histological damage, the levels of inflammatory cytokines in lung and bronchoalveolar lavage fluid (BALF), lung wet/dry weight ratio, as well as total protein levels in BALF. We also observed that LXHX ameliorated pulmonary oxidative damage in CLP-induced mice. In addition,LXHX dramatically prevented the CLP-induced pulmonary cell apoptosis as presented by reduced TUNEL-positive lung cells and expression of Bcl2 and enhanced expressions of Bax.Our results showed that CLP inhibited SIRT1 and Nrf2 expressions while activating NF-κB, however LXHX could increase SIRT1 and Nrf2 expression and inactivate NF-κB.Notably,all these protective effects of LXHX were abrogated by EX527.In conclusion,LXHX protects against CLP-induced ALI by restoring the composition and diversity of intestinal flora,suppressing inflammation,oxidative stress and apoptosis. These beneficial effects might be mediated by through activation of the SIRT1/Nrf2 pathway and inhibition of NF-κB signaling.