Figure 3.

Opioid-induced gut microbiota dysbiosis. The long-term effects of opioid treatment on the intestines are: (A) Directly weakening gastrointestinal motility, commonly resulting in complications such as constipation. Changes in intestinal motility and transit time further alter the composition of the intestinal microbiota and cause translocation of gut microbiota. (B) Directly altering the composition and dysbiosis of the intestinal microbiota, such as a decrease in Lactobacillus and Bifidobacterium, an increase in Staphylococcus and Enterobacter, and potentially increasing other pathogenic bacteria. (C) Damage to the intestinal epithelial barrier (increased permeability, disruption of tight junction proteins, decreased immune function). The dysregulation of intestinal microbiota and function ultimately affects systemic inflammation and contributes to the development of opioid resistance via the gut-brain axis (Acharya et al., 2017; Bhave et al., 2017; Guo et al., 2019; Zhang et al., 2019a).