Sex-dependent responses in mice to indomethacin-induced organ injury and gut microbiome-targeted alleviation

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used widely but produce gastrointestinal (GI) toxicities in both short- and long-term users. Previous studies have shown that the intestinal microbiota play an important role in gut damage and that gut microbial β-glucuronidase (GUS) inhibitors can alleviate NSAID-induced injury in male mice by blocking the GI reactivation of NSAID-glucuronides. Here, in both male and female C57BL/6 mice, we examine the effects of indomethacin alone and with the GUS inhibitor UNC10201652. Oral delivery of 5 mg/kg body weight indomethacin over 5 days decreased body weight, induced colonic and hepatic inflammatory cytokine gene expression, and enlarged the spleens of both male and female mice. However, sex-specific inflammatory responses to indomethacin were observed, with males demonstrating more colonic injury while females presented greater splenic and hepatic toxic responses. Females also showed a unique indomethacin-induced bloom of fecal Verrucomicrobia as measured by 16S rRNA metagenomic sequencing. UNC10201652 alleviated aspects of these indomethacin-induced toxicities, including features of the male-specific colonic damage and the female-specific compositional changes and spleen and liver toxicities. Thus, GI and non-GI tissues in male and female mice respond distinctly to indomethacin-induced damage. These findings advance our understanding of how sex impacts systemic responses to xenobiotic exposure and may lead to improved therapeutic outcomes with these widely used drugs.