Vitor Hugo Santos
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João Pedro Hübbe Pfeifer
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Fernanda de Castro Stievani
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Gustavo Santos Rosa
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Emanuel Vitor Pereira Apolonio
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Abstract
BackgroundOsteoarthritis is the main cause of equine lameness and its treatment remains ineffective. Synovial membrane mesenchymal stem cells (SMMSC) provide satisfactory outcomes in joint injuries, mainly due to their immunomodulatory and reparative properties. This study aimed to evaluate the effect of MSMSC, either encapsulated in alginate hydrogel or free, in chondral lesions of horses.MethodsChondral lesions were surgically induced in medial trochlea of talus of fifteen horses. Animals were treated with PBS, 1x107 free SMMSC or 1x107 encapsulated SMMSC. Physical evaluations, lameness scores and synovial fluid analysis were determined (cytological analysis and dosage of IL-1, IL-10, IL-6, INF-Ɣ, TNF 𝛼, P Substance, Serum Amyloid A, TGF-β, IGF and PGE2) initially and followed for up to two weeks. Cartilage biopsies were performed 150 days after the induction for histological analysis and immunohistochemistry staining.ResultsAll groups presented inflammation initially. Although free SMMSC showed moderate tissue repair, encapsulated SMMSC modulated inflammation and had the lower grade of inflammation with superior tissue macro and microscopic aspects at the end, while the control group showed fibrosis and poor cartilage appearance. This study suggests better stem cell effectiveness in chondral defects when encapsulated MSCs are used.ConclusionsWhile the absence of treatment perpetuates cartilage degradation, encapsulated SMMSC responded better to the initial inflammation, interacting and modulating the environment through the release of anti-inflammatory cytokines. Better outcomes observed in encapsulated MSCs were related to the immuno and physical barrier provided by the alginate hydrogel, allowing a longer period of permanence and interaction between MSCs and the environment.