| Abstract ID |
| 20260034 |
| Category |
| Basic Science and Biologic Repair |
| Preferable Presentation |
| Both |
| Title |
| AP9578 PROMOTED INFLAMMATION RESOLUTION OF TENDON-DERIVED STEM/PROGENITOR CELLS AND EARLY TENDON HEALING IN A COLLAGENASE-INDUCED TENDON INJURY RAT MODEL |
| Author |
|
| Presenter |
| Pauline Po Yee LUI |
| Abstract |
| Background Tendinopathy is a chronic degenerative tendon disorder resulting from overuse or aging, leading to local tenderness, swelling, and pain that significantly limits physical activity. Current treatment options are often inadequate due to a limited understanding of the underlying mechanisms. AP9578 is a protective and healing factor of gut mucosa, playing diverse roles in the immune system and in inflammatory responses following injury or infection. To date, no studies have examined the presence and functions of AP9578 in musculoskeletal tissues. Our unpublished results showed that it is upregulated in human tendinopathy tissues, suggesting its potential role in the healing of degenerative tendons in patients with tendinopathy. Objectives This study aimed to investigate the effects of AP9578 on the inflammatory responses and functions of tendon-derived stem/progenitor cells (TDSCs), as well as tendon healing in a rat collagenase-induced patellar tendon injury model (CI model). Study design One patellar tendon from each male Sprague-Dawley rat (12 weeks old) was injected with either saline or collagenase. Three days after the injection, the animals were divided into four groups: (1) Saline + GelMA; (2) Collagenase + GelMA; (3) Collagenase + GelMA loaded with AP9578 (0.1 mg). At weeks 2 and 4 following the injection, the patellar tendons were harvested for histological analysis and stained with hematoxylin and eosin. Rat patellar tendon-derived stem cells (TDSCs) were treated with or without IL-1β (10 ng/mL) and AP9578 for 24 or 48 hours. The optimal dose of AP9578 was determined based on cell viability assessed using the Alamar Blue reduction assay. The effect of this optimal dose of AP9578 on cell migration was assessed by transwell assay. The expression of inflammatory enzymes (Il1b, Nos2) and matrix-degrading enzymes (Mmp13) was analysed by qRT-PCR. Results AP9578 promoted tendon healing at weeks 2 and 4 post-treatment, as evidenced by a reduction in cellularity and vascularity, as well as an increase in cell alignment compared to the collagenase + GelMA group. At a dose of 10 ng/mL, AP9578 demonstrated the highest cell viability on the IL-1β-treated cells compared to the IL-1β-only group (p<0.01), and this dose was used in all subsequent experiments. AP9578 at the optimal dose enhanced cell viability (p<0.01) and migration (p<0.01) of IL-1β-treated cells, while simultaneously reducing the expression of inflammatory cytokines and matrix-degrading enzymes (all p<0.05). Conclusions AP9578 promoted early healing of CI tendon injuries. It enhances the viability and migration of inflammatory TDSCs and reduces the expression of inflammatory cytokines and matrix-degrading enzymes in these cells. Future work will involve validating the qRT-PCR data at the protein level and exploring the long-term effects and molecular mechanisms of AP9578 in animal models. Acknowledgement This study was funded by the General Research Fund of Research Grant Council (Ref. 14116225) and supported in part by InnoHK Initiative of the Innovation and Technology Commission of the Hong Kong Special Administration Region Government. |