Peripheral nerve injuries often lead to painful neuroma formation and chronic neuropathic pain, and the optimal surgical strategy for prevention remains debated. Targeted muscle reinnervation (TMR), r Show more
Peripheral nerve injuries often lead to painful neuroma formation and chronic neuropathic pain, and the optimal surgical strategy for prevention remains debated. Targeted muscle reinnervation (TMR), regenerative peripheral nerve interfaces (RPNI), and nerve-in-muscle implantation (NIM) are surgical techniques developed to mitigate neuroma-related pain, but their relative efficacy has not been compared systematically. This preclinical study compared TMR, NIM, and two RPNI variants in a rat tibial nerve transection model to identify which approach best reduces neuroma formation and pain. Sprague-Dawley rats underwent right tibial nerve transection and were randomized into five groups: control (no repair), NIM, W-RPNI (wrapped RPNI), E-RPNI (embedded RPNI), or TMR. Behavioral outcomes including gait analysis (CatWalk), mechanical hypersensitivity (von Frey test), thermal hyperalgesia (Hargreaves test), and neuroma tenderness were assessed over 12 weeks. At week 12, distal nerve stumps and L4-L5 dorsal root ganglia (DRG) were harvested for histological evaluation, immunohistochemistry/immunofluorescence, and molecular analyses (qRT-PCR and Western blot) targeting pain- and inflammation-related biomarkers. By 12 weeks, TMR-treated rats showed the most robust improvements, including significantly longer stance duration, larger paw contact area, near-baseline withdrawal thresholds, and minimal neuroma tenderness, whereas untreated controls developed gross neuromas and persistent hypersensitivity. TMR also preserved organized nerve architecture with orderly axonal regeneration and minimal collagen I/III fibrosis at the stump. Molecular assays confirmed that TMR markedly attenuated nociceptive and inflammatory signaling, with TMR rats exhibiting the lowest expression of pain-related mediators (c-Fos, TRPA1, TRPV1, CGRP, NPY, BDNF) and pro-inflammatory/fibrotic markers (galectin, α-SMA, IL-1β, TNF-α, TGF-β) in nerve and DRG tissues. Conversely, the anti-inflammatory cytokine IL-10 and axonal ion pump subunits ATP1A2/ATP2B1 were significantly upregulated with TMR. Outcomes for the two RPNI groups were similar to each other and generally intermediate between TMR and control. TMR was superior to RPNI variants and NIM in preventing neuroma formation and alleviating neuropathic pain in this animal model. These findings support TMR as a promising surgical strategy to mitigate post-amputation neuroma pain. Show less
The gut microflora is a vital component of the gastrointestinal (GI) system that regulates local and systemic immunity, inflammatory response, the digestive system, and overall health. Older people co Show more
The gut microflora is a vital component of the gastrointestinal (GI) system that regulates local and systemic immunity, inflammatory response, the digestive system, and overall health. Older people commonly suffer from inadequate nutrition or poor diets, which could potentially alter the gut microbiota. The essential amino acid (AA) tryptophan (TRP) is a vital diet component that plays a critical role in physiological stress responses, neuropsychiatric health, oxidative systems, inflammatory responses, and GI health. The present study investigates the relationship between varied TRP diets, the gut microbiome, and inflammatory responses in an aged mouse model. We fed aged mice either a TRP-deficient (0.1%), TRP-recommended (0.2%), or high-TRP (1.25%) diet for eight weeks and observed changes in the gut bacterial environment and the inflammatory responses via cytokine analysis (IL-1a, IL-6, IL-17A, and IL-27). The mice on the TRP-deficient diets showed changes in their bacterial abundance of Coriobacteriia class, Show less