Ly6Chi Monocytes Provide a Link between Antibiotic-Induced Changes in Gut Microbiota and Adult Hippocampal Neurogenesis

TLDR

Antibiotics can disrupt gut microbiota and produce adverse effects. The study aims to determine whether Ly6Chi monocytes mediate the recovery of neurogenesis and behavior after antibiotic-induced gut microbiota changes. Antibiotic treatment lowers hippocampal neurogenesis and memory, but exercise or probiotics restore them by elevating Ly6Chi monocytes, whose depletion diminishes and transfer rescues neurogenesis.

Abstract

Antibiotics, though remarkably useful, can also cause certain adverse effects. We detected that treatment of adult mice with antibiotics decreases hippocampal neurogenesis and memory retention. Reconstitution with normal gut flora (SPF) did not completely reverse the deficits in neurogenesis unless the mice also had access to a running wheel or received probiotics. In parallel to an increase in neurogenesis and memory retention, both SPF-reconstituted mice that ran and mice supplemented with probiotics exhibited higher numbers of Ly6Chi monocytes in the brain than antibiotic-treated mice. Elimination of Ly6Chi monocytes by antibody depletion or the use of knockout mice resulted in decreased neurogenesis, whereas adoptive transfer of Ly6Chi monocytes rescued neurogenesis after antibiotic treatment. We propose that the rescue of neurogenesis and behavior deficits in antibiotic-treated mice by exercise and probiotics is partially mediated by Ly6Chi monocytes.