Izda, V. A. | bioRxiv Science

bioRxiv2024

Transcutaneous Vagus Nerve Stimulation Reduces Pain and OA Progression in Mouse Models of Post-Traumatic Osteoarthritis

Currently, there are no disease-modifying osteoarthritis (OA) drugs (DMOAD) to prevent OA progression and there are limitations on pain relieving therapeutics. Vagus nerve stimulation (VNS) delivered by an implantable device is FDA-approved for refractory epilepsy and severe depression. Here, we investigated the efficacy of transcutaneous VNS (tVNS) for preventing OA progression and providing pain relief in two mouse models of post-traumatic OA (PTOA): the surgical destabilized medial meniscus (DMM) and the non-surgical forced tibial compression anterior cruciate ligament rupture (ACLR). Here, we show that 2 weeks of tVNS significantly reduced histological OA scores in male and female mice after ACLR compared to sham stimulation. In female, but not male, mice, tVNS reduced hyperalgesia and mechanical allodynia. In the slower DMM model, 8 weeks of tVNS improved weight bearing in male and female mice, but only female mice had improved hyperalgesia. Male mice had lower OA histological scores. Serum proinflammatory cytokines were significantly reduced by tVNS in both models but differed by gender and model. Overall, these results provide strong pre-clinical evidence that tVNS reduces OA progression, improves pain, and suppresses pro-inflammatory cytokines, making it a promising DMOAD.

physiology↗

bioRxiv2021

Ear wound healing in MRL/MpJ mice is associated with gut microbiome composition and is transferable to non-healer mice via microbiome transplantation

ObjectiveAdult cartilage has limited repair capacity. MRL/MpJ mice, by contrast, are capable of spontaneously healing ear punctures. This study was undertaken to characterize microbiome differences between healer and nonhealer mice and to evaluate microbiome transplantation as a novel regenerative therapy. MethodsWe transplanted C57BL/6J mice with MRL/MpJ cecal contents in mice at weaning and as adults (n=57) and measured earhole closure 4 weeks after a 2.0mm punch and compared to vehicle-transplanted MRL and B6 (n=25) and B6-transplanted MRL (n=20) mice. Sex effects, timing of transplant relative to earpunch, and transgenerational heritability were evaluated. In a subset (n=58), cecal microbiomes were profiled by 16S sequencing and compared to earhole closure rates. Microbial metagenomes were imputed using PICRUSt. ResultsTransplantation of B6 mice with MRL microbiota, either in weanlings or adults, improved earhole closure rates. Transplantation prior to ear punch was associated with the greatest earhole closure. Offspring of transplanted mice healed better than controls. Several microbiome clades were correlated with healing, including Firmicutes, Lactobacillales, and Verrucomicrobia. Gram-negative organisms were reduced. Females of all groups tended to heal better than males, female microbiota resembled MRL mice. ConclusionIn this study, we found an association between the microbiome and tissue regeneration in MRL mice and demonstrate that this trait can be transferred to nonhealer mice via microbiome transplantation. We identified several microbiome clades associated with healing. Future studies should evaluate the mechanisms underlying these findings and confirm our results in murine OA.

molecular biology↗