Gut Microbiota Mitigates Chronic Itch and Cutaneous Inflammation in DNFB-Induced Atopic Dermatitis Mice.

Background: Chronic itch is the most prominent symptom of atopic dermatitis (AD), which severely impacts the quality of life of patients and persists even after medication. Gut microbiota dysbiosis is considered to contribute to AD, however, the roles of gut microbiota in the modulation of chronic pruriceptive processing currently remain unclear. The present study aimed to elucidate the potential regulatory role of the gut microbiota in AD-associated chronic itch. Methods: In this study, the 1-fluoro-2,4-dinitrobenzene (DNFB)-induced mouse model of AD-associated chronic itch was established. Differences in gut microbiota composition between model and healthy controls were analyzed using high-throughput 16S rRNA gene sequencing. In addition, we performed oral fecal microbiota transplantation (FMT) from model mice to antibiotic cocktail-treated healthy mice and observed whether they could induce itch behavior. Furthermore, feces from healthy mice were transplanted into model mice to evaluate their effects on itch symptoms and skin inflammation. Results: The DNFB induced significantly itch behaviors and an altered gut microbiota composition. The gut microbiota from chronic itch mice through oral administration could induce itch behaviors in antibiotic cocktail-treated healthy mice. While, oral FMT from healthy mice to chronic itch mice not only significantly alleviated scratching behavior but also ameliorated skin damage and inflammation. Following FMT administration from healthy donors, remarkable alterations were observed in the metabolomic profiles of mice with DNFB-induced chronic itch. Conclusion: These findings highlight the potential link between gut microbiota dysbiosis and chronic itching in AD, suggesting that targeting the gut microbiota may be a therapeutic strategy for chronic itch.