Effects of antibiotics on colonic neurons of the myenteric plexus in wild Peromyscus mice

Abstract

A community of trillions of commensal bacteria inhabit the gastrointestinal tract - collectively known as the intestinal microbiota. The gut microbes are essential for the development and functioning of the enteric nervous system. Approximately two-thirds of the cell bodies of all enteric neurons are gathered in the myenteric plexus – an intricate network of neurons and glial cells that primarily regulate gut neuromuscular activity. Studies in laboratory rodents have observed that antibiotic treatment leads to a reduction in microbial abundance and diversity within the intestine and these findings are correlated with enteric nervous system structural abnormalities. Specifically, antibiotic-treated mice have an abnormal myenteric plexus characterized by a reduction in myenteric neuron numbers and ganglia area. However, it is unknown whether these effects occur in wild Peromyscus mice that are exposed to a natural bacterial flora. The goal of this study was to evaluate the effects of antibiotic exposure on the colonic neurons of the myenteric plexus in wild Peromyscus mice. Thirty-two wild-caught adult male Peromyscus mice were divided into control and antibiotic-treated groups. Whole mount preparations of longitudinal muscle with adherent myenteric plexus were prepared and alterations in colonic neuron and ganglia numbers were assessed by immunohistochemistry analysis. Antibiotic-treatment reduced the total number of colonic enteric neurons/mm² and the total number of ganglia per myenteric plexus. Our results suggest that antibiotic-induced microbial dysbiosis affects the colonic neurons and ganglia of wild Peromyscus mice similarly to laboratory rodents.