Rhubarb alleviates acute lung injury by modulating gut microbiota dysbiosis in mice

Abstract Purpose Intestinal microbiota disorders can aggravate pulmonary inflammation during acute lung injury (ALI). Rhubarb, a Chinese herb, can regulated the gut microbiota. Therefore, this study was conducted to test the hypothesis that rhubarb alleviates gut microbiota dysbiosis and inflammation. Methods Feces were collected from patients with ALI to detect the gut microbiota using 16S rDNA sequencing. Subsequently, a mouse model of ALI was established using lipopolysaccharide to investigate changes in the gut microbiota, the periperal blood was attained for detecting the Th17/Treg cell ratio and the serum level of HDAC6 and HDAC9, and the effect of rhubarb treatment on the gut microbiota and Th17/Treg ratio were also evaluated. Results Both the Firmicutes phyla decreased and the Bacteroidetes increased were identified in patients with ALI, which induced the alternation of histone metabolites. The rat models also showed a similar imbalance in the Firmicutes/Bacteroidetes ratio. Rhubarb treatment alleviated the damaged lung tissue, accelerated Alistipes, Clostridiales and Lactobacillus proliferation, increased the level of HDAC6 in both the mice lung tissue and serum, and markedly reduced the Treg cells and increased the Th17 cells in the spleen tissue. Conclusion we determined that both patients and mouse models presented gut microbiota dysbiosis and Th17/Treg cell imbalances. Rhubarb promoted Alistipes, Clostridiales and Lactobacillus proliferation, increased the HDAC6 concentration, restored the Th17/Treg cell balance, and protected against ALI.