Alteration of the gut microbiota in tumor necrosis factor-α antagonist-treated collagen-induced arthritis mice

Aim Gut microbiota play an important role in rheumatoid arthritis (RA). Biological therapies targeting tumor necrosis factor-alpha (TNF-alpha) have been used for treatment in RA patients. However, whether TNF-alpha antagonist has some influence on gut microbiota is still unknown. This study aims to investigate the distribution of gut microbiota in collagen-induced arthritis (CIA) mice treated with the TNF-alpha antagonist etanercept. Methods Collagen-induced arthritis mice were induced by type II collagen. Cytokine expression was detected by real-time polymerase chain reaction. 16S ribosomal RNA sequencing was performed to characterize the gut microbiota in CIA mice treated with vehicle or etanercept. Sequencing reads were processed by Microbial Ecology software program. Results Compared with vehicle-treated mice, we showed that CIA mice treated with etanercept led to attenuation of inflammation and reduced expression of TNF-alpha, interferon (IFN)-gamma, interleukin (IL)-6 and IL-21. Meanwhile, results showed operational taxonomic units, richness estimators and the diversity indices of gut microbiota in etanercept-treated mice were lower than that in vehicle-treated mice. Moreover, bacterial abundance analyses showed that genus Escherichia/Shigella was more abundant in etanercept-treated mice, and Lactobacillus, Clostridium XlVa, Tannerella were less abundant. The altered bacterial genus was correlated with TNF-alpha, IFN-gamma, IL-6, IL-21 and IL-10. Conclusion Our results revealed that TNF-alpha antagonist treatment can reduce the abundance and diversity of gut microbiota in CIA mice. Targeted gut microbiota may be a new therapeutic strategy for the treatment of RA.