Therapeutic effects of Mongolian medical warm acupuncture on neuropathic pain via gut microbiota and inflammatory pathway regulation in a chronic constriction injury rat model

The study was designed to determine whether Mongolian medical warm acupuncture (MMWA) can alleviate neuropathic pain through regulating gut microbiota and inflammation-related pathways in the chronic constriction injury (CCI) rat model. Rats were randomly divided into three groups: sham, model, and treatment. A bilateral chronic constriction injury (CCI) was induced to establish a rat model of neuropathic pain. Rats in the treatment group received MMWA at the Heyi and Shen acupoints once daily for seven consecutive days. Pain-related behaviors were evaluated using mechanical pain threshold and thermal withdrawal latency measurements. The mRNA levels of c-fos in spinal dorsal horns were determined using real-time PCR. Gut microbiota was analyzed by 16S ribosomal RNA sequencing. Interleukin (IL)-1?, IL-6, and tumor necrosis factor (TNF)-? were evaluated by enzyme-linked immunosorbent assay (ELISA) analysis. MMWA could relieve behavioral symptoms (P<0.01). MMWA intervention significantly suppressed the expression of c-fos in CCI rats (P<0.05). The relative abundance of gut bacteria was disturbed in CCI rats, with the microbiota disorder ameliorated by MMWA. KEGG enrichment analysis revealed that changes in gut microbiota were associated with the pentose and glucuronate interconversion pathway and secondary bile acid biosynthesis. The concentrations of IL-1?, IL-6, and TNF-? in CCI rats were increased (P<0.05), an effect that was reversed by MMWA intervention (P<0.05). The current study indicated that the MMWA could effectively alleviate neuropathic pain by modulating gut microbiota and inhibiting inflammation in the CCI rat model, suggesting that gut microbiota could be a promising potential biological target for treating neuropathic pain.