Project description:We investigated calcaneal tendon extracellular matrix (ECM) remodeling after gastrocnemius muscle injury using a rat model. Wistar rats were randomly divided into four groups: control group (C; animals that were not exposed to muscle injury) and harvested at different time points post gastrocnemius muscle injury (3, 14 and 28 days) for gene expression analysis. qRT-PCR was performed using TaqMan Universal PCR Master Mix system (Applied Biosystems, CA, USA - Cat. 4304437).
Project description:Partial tendon-to-bone interface (TBI) injuries heal in a mechanically inferior manner and redevelop healthy uninjured tissue morphology. The origin of the cells involved in tendon-to-bone healing remains unknown. We employed a rigorous approach to evaluate if mouse skeletal stem cells (mSSC) play a role in tendon-to-bone healing after partial-injury. Using fluorescence-activated cell sorting we identified that found that they are present within the TBI. Using a TBI-injury rainbow lineage tracing mouse model, we demonstrated that injury-responsive cells within the TBI and calcaneus proliferate polyclonally following partial-tendon injury at the TBI. These injury-responsive clonal cells express skeletal marker SP7. We quantified the differences in mSCC frequency after TBI-injury and found that mSSC respond to injury with a higher frequency and have associated changes in gene expression, with the specific down-regulation of the TGFβ signaling pathway. Exogenous delivery of TGFβ after injury was found to reduce the mSSC response after injury. These findings suggest that mSSC may facilitate tendon-to-bone healing by downregulating TGFβ signaling within the mSSC niche.
Project description:Injury was induced in the left Achilles tendon by needle puncture. Rats were sacrificed 4 and 21 days post injury. Shams, in which the tendon was isolated but not punctured, were included as controls. Serum was collected post-mortem and RNAseq used to identify differentially expressed ncRNAs.
Project description:The rat tendon injury models were established and divided into three groups: normal control group, injury model group, and celecoxib + lactoferrin treatment group. Then, RNA sequencing and differential expression analysis were performed for samples from injury model group and celecoxib + lactoferrin treatment group on day 14. Next, autophagy/hypoxia/ferroptosis/pyroptosis-related genes retrieved from the corresponding databases and related literatures were downloaded to obtain the genes associated with autophagy/hypoxia/ferroptosis/pyroptosis. Subsequently, functional annotation, protein-protein interaction (PPI) network and transcriptional regulatory network construction for these genes were performed.
Project description:Intralesional mesenchymal stem cell (MSC) therapy has improved tissue architecture and reinjury rates in equine tendon injury; however, the mechanisms by which they promote repair are still being investigated. Therefore, the objectives of this study were to determine how the predominate pro-inflammatory cytokines present in a surgically induced model of equine tendon injury modulate MSC gene and protein expression.
Project description:Tendon is a hypocellular tissue that contains functional cable-like units of type I collagen responsible for the transmission of force from muscle to bone. In the setting of injury or disease, patients can develop chronic tendinopathies that are characterized by pain, loss of function and persistent inflammatory changes that are often difficult to treat. Platelet-rich plasma (PRP) has shown promise in the treatment of chronic tendinopathy, but little is known about the mechanisms by which PRP can improve tendon healing. PRP contains many different growth factors and cytokines, and since these proteins can both activate and inhibit various signaling pathways it has been challenging to determine precisely which signaling pathways and cellular responses are most important. Using state-of-the-art bioinformatics tools and genome wide-expression profiling, the purpose of this study was to determine the signaling pathways activated within cultured tendon fibroblasts in response to PRP treatment. Tendon fibroblasts were isolated from rat tail tendons and embedded in 3D type I collagen gels. Cells were treated with PRP or PPP for 24 hours, and total RNA was extracted for hybridization on Affymetrix arrays.
Project description:scRNA and snATAC sequencing of cells harvested from the tendon injury site after a severe burn/tenotomy injury in Hoxa11 lineage traced mice allowed for differentation tracing of MSCs located in zeugopod after severe heterotopic ossification inducing injury. The use of immobilization also allowed us to determine the effects of limb immoblization on MSCs during aberrant wound healing.