RETNLB and serum lipopolysaccharide activity: Taking these observations together, protection against MCD diet-induced impaired gut permeability in RELMβ-KO mice might be partially attributable to this Lactobacillus increase, and RELMβ-induced gut microbiota change might be involved in the impairment of gut permeability and the induction of endotoxemia, and thereby in the hepatic inflammation observed in this study.