Gut microbiota: A critical regulator of oxaliplatin-induced peripheral neurotoxicity development

Oxaliplatin-induced peripheral neuropathy (OIPN) is a common dose-limiting toxicity that significantly affects patients' quality of life. Although neuroinflammation has been implicated, the precise contribution of the gut-nerve axis remains incompletely understood. This study aimed to investigate the role of gut microbiota and associated inflammatory signaling in OIPN.

An OIPN model was established in Sprague Dawley rats. Gut microbiota depletion was achieved via antibiotic (ABX) treatment, and fecal microbiota transplantation (FMT) from healthy donors was performed to restore microbial communities. Mechanical allodynia and cold hypersensitivity were assessed using the von Frey filament test and the acetone test, respectively. Systemic inflammation was evaluated by measuring serum cytokine levels via enzyme-linked immunosorbent assay (ELISA). The composition of the gut microbiota was analyzed by 16S rRNA gene sequencing. Intestinal barrier integrity and local inflammation were assessed through histopathology, immunofluorescence, and quantification of tight junction proteins (ZO-1, occludin) and inflammatory markers (NF-κB, TNF-α) via quantitative polymerase chain reaction (qPCR) and Western blotting. Network pharmacology was employed to screen for potential common targets of oxaliplatin and neurotoxicity. Molecular alterations in the dorsal root ganglia (DRG) were examined using histology, qPCR, Western blotting, and immunofluorescence, with a focus on the TLR4/MyD88/NF-κB signaling pathway and pro-inflammatory cytokines.

Antibiotic-mediated depletion of gut microbiota significantly attenuated OXA-induced neuropathic pain and systemic inflammation, as evidenced by reduced levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1beta (IL-1β), whereas FMT reversed these protective effects. Analysis of 16S rRNA gene sequencing revealed that OXA altered gut microbiota composition, including reduced alpha diversity, altered beta diversity, a decreased Firmicutes/Bacteroidetes ratio, and taxonomic changes. These alterations were partially restored following FMT under the present experimental conditions. Functional prediction analysis indicated enrichment of the lipopolysaccharide (LPS) biosynthesis pathway. Consistently, OXA treatment was associated with elevated LPS levels in plasma and feces, which were reduced by ABX treatment and increased following FMT. OXA was also associated with impaired intestinal barrier integrity, as evidenced by decreased expression of ZO-1 and Occludin and increased inflammatory markers (NF-κB, TNF-α) in the colon, changes that were modulated by microbiota status. Network pharmacology analysis identified inflammation-related pathways and potential targets. In the DRG, OXA treatment was associated with neuronal injury, increased expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-8), and activation of the TLR4/MyD88/NF-κB signaling pathway, which were attenuated by antibiotic treatment and reappeared following FMT.

These findings support a microbiota-associated contribution to OIPN and suggest that gut microbiota may influence intestinal and peripheral inflammatory responses. Increased endotoxin burden and activation of TLR4-related signaling pathways may represent potential mechanisms linking the gut and nervous system in OIPN. Targeting the gut-nerve axis may offer a promising direction for future therapeutic strategies, although further studies are required to establish causality and identify specific microbial mediators.