Fibroproliferative disorders occur in both humans and horses following skin injury. In horses, wound healing on the limb is often complicated by the formation of fibroproliferative exuberant granulation tissue, characterized by persistent expression of pro-fibrotic transforming growth factor-beta1 (TGF-β1) and deficient expression of anti-inflammatory interleukin-10 (IL-10). IL-10 has been shown to directly modulate fibrotic gene expression in human fibroblasts, so we hypothesized that equine IL-10 (eIL-10) may exert similar anti-fibrotic effects on equine dermal fibroblasts. Cell-lines were created from the limb skin of six individual horses. Recombinant eIL-10 was produced and purified, and its effects on the cells investigated in the presence and absence of equine TGF-β1 (eTGF-β1). Myofibroblast differentiation and collagen production were examined using immunofluorescent cytometry, cell contractility in a collagen gel assay, and fibrotic gene expression using quantitative PCR. In response to eTGF-β1, fibroblasts increased in contractility and expression of alpha-smooth muscle actin, collagen types 1 and 3, and matrix metalloproteinase 1, 2, and 9. Equine IL-10 limited cell contractility and production of alpha-smooth muscle actin and type 3 collagen, and decreased mRNA levels of eCol3a1 and eMMP9, while increasing that of eMMP1. Opposing effects on eTGF-βR3 and eIL-10R1 gene expression were also observed, with mRNA levels decreasing following eTGF-β1 treatment, and increasing with eIL-10 treatment. These findings indicate that eIL-10 limits the pro-fibrotic effects of eTGF-β1, potentially through the modulation of fibrotic and receptor gene expression. Further investigations are warranted to assess the therapeutic utility of eIL-10 in the treatment of exuberant granulation tissue.

皮肤损伤后，人和马都发生纤维增生性疾病。在马中，肢体的伤口愈合通常由于形成纤维增生旺盛的肉芽组织而变得复杂，其特征是持续表达促纤维化转化生长因子-β1（TGF-β1）和抗炎性白介素10（IL）的表达不足-10）。IL-10已显示可直接调节人成纤维细胞中纤维化基因的表达，因此我们假设马IL-10（eIL-10）可能对马真皮成纤维细胞发挥类似的抗纤维化作用。细胞系是由六匹单独的马的肢体皮肤创建的。产生并纯化了重组eIL-10，并在有和没有马TGF-β1（eTGF-β1）的情况下研究了其对细胞的作用。使用免疫荧光细胞计数法检查成肌纤维细胞的分化和胶原蛋白的产生，使用胶原蛋白凝胶测定法检查细胞的收缩性，并使用定量PCR检测纤维化基因的表达。响应eTGF-β1，成纤维细胞的收缩力和α平滑肌肌动蛋白，1型和3型胶原蛋白以及基质金属蛋白酶1、2和9的表达增加。马IL-10限制了细胞的收缩力和α平滑肌的产生肌动蛋白和3型胶原蛋白，以及降低的mRNA水平eCol3a1 和 eMMP9，同时增加 eMMP1。相反的影响转化生长因子βR3 和 eIL-10R1还观察到基因表达，eTGF-β1处理后mRNA水平降低，而eIL-10处理后mRNA水平升高。这些发现表明eIL-10可能通过调节纤维化和受体基因表达来限制eTGF-β1的促纤维化作用。有必要做进一步的研究来评估eIL-10在旺盛的肉芽组织中的治疗作用。