A High-Fiber Diet or Dietary Supplementation of Acetate Attenuate Hyperoxia-Induced Acute Lung Injury.

A high fiber diet (HFD) and dietary supplementation with acetate have been reported to have beneficial effects in a variety of diseases. We investigated the effects of a HFD and acetate supplementation on the gut microbiota and hyperoxia-induced acute lung injury (HALI) in mice. Mice were fed a control diet, HFD, or acetate supplementation for three weeks, and their gut microbiome composition, lung tissues, and bronchoalveolar lavage fluid (BALF) were examined after exposure to ambient air or hyperoxia. Both the HFD and acetate supplementation modified the gut microbiota community and increased the proportion of acetate-producing bacteria in mice exposed to hyperoxia. The HFD and acetate supplementation also increased the abundance of Bacteroides acidifaciens and reduced gut dysbiosis according to the ratio of Firmicutes to Bacteroidetes. Compared with hyperoxia-exposed mice fed a control diet, both the HFD and acetate supplementation significantly increased the survival time while reducing the severity of pulmonary edema and the concentrations of protein and inflammatory mediators in BALF. Moreover, the HFD and acetate supplementation reduced the production of free radicals, attenuated NF-κB signaling activation, and decreased apoptosis in the lung tissues. Overall, this study indicates that a HFD or acetate supplementation reduces the severity of HALI through alterations in the gut microbiota to exert anti-inflammatory effects.