Differential alteration in gut microbiome profiles during acquisition, extinction and reinstatement of morphine-induced CPP

Substance addiction is a chronic and complicated disease involving genetic and environmental factors. Coregulated by the above factors, perturbations of the gut microbiome have been shown to have an essential role in the development of many neuropsychiatric disorders, including addiction. However, shifts in the gut microbiome during different stages of morphine addiction remain uncharacterized. In the present study, we harvested fecal samples from mice at the acquisition (both the control and morphine groups), extinction and reinstatement stages of morphine-induced conditioned place preference (CPP). Gut microbiome profiles were detected with 16S ribosomal RNA gene sequencing. We observed an increase in community richness following morphine conditioning, and it decreased after 4 weeks of abstinence. The abundance of Verrucomicrobia increased and Bacteroides decreased at the acquisition of morphine-induced CPP, while a recovery trend was found at the extinction stage. Several discriminative genera were identified for the characterization of different stages of morphine CPP. Functional analysis of taxa with differential abundance between CPP stages was mainly enriched in the pathways of amino acid metabolism. Taken together, our findings will extend the association between dysbiosis of the gut microbiome and the opioid-induced rewarding or reinforcing behaviors.

Automated summary

This study investigated the changes in gut microbiome profiles during different stages of morphine addiction in mice using 16S ribosomal RNA gene sequencing. The results showed an increase in community richness after morphine conditioning, which decreased after a 4-week abstinence period. Specific genera abundance changed at the acquisition stage of morphine-induced CPP, with a recovery trend observed during the extinction stage.