Gut microbiota-derived propionate alleviate traumatic painful neuroma through inhibiting the RIG-I-NF-κB-mediated neuroinflammation.

Traumatic painful neuroma (TPN) is a debilitating condition that frequently develops after peripheral nerve injury, yet its pathogenesis remains poorly elucidated. Growing evidence implicates the gut microbiota in the regulation of pain and inflammatory processes, but its specific role in TPN has not been investigated. This study examines the contribution of the gut microbiota and its metabolite propionate to TPN development via modulation of the RIG-I-NF-κB signaling pathway. In a murine model of sciatic nerve transection, we identified distinct gut microbial communities between TPN-susceptible and non-susceptible mice, characterized by a reduction in beneficial bacteria and decreased fecal propionate levels in TPN-prone mice. Depletion of gut microbiota through antibiotic treatment aggravated neuroma formation and pain-like behaviors, effects that were reversible by fecal microbiota transplantation (FMT). Administration of propionate dose-dependently ameliorated neuroinflammation, fibrotic progression, and pain responses. Mechanistic studies revealed that propionate suppressed the RIG-I-NF-κB pathway activation, downregulated pro-inflammatory cytokines, and enhanced intestinal barrier integrity. Notably, FMT from propionate-treated mice replicated these protective outcomes. Our results indicate that gut microbiota-derived propionate mitigates TPN by inhibiting RIG-I-NF-κB-driven neuroinflammation and preserving gut barrier function, underscoring the gut-brain-nerve axis as a promising target for TPN therapy.