Regenerative Medicine, Future Industries Institute, University of South Australia, Adelaide, South Australia, Australia.
Faculty of Medicine and Health, University of Adelaide, Adelaide, South Australia, Australia.
J Orthop Surg Res. 2020 Aug 27;15(1):362. doi: 10.1186/s13018-020-01889-y.
Surgical repair of tendons is common, but function is often limited due to the formation of flexor tendon adhesions which reduce the mobility and use of the affected digit and hand. The severity of adhesion formation is dependent on numerous cellular processes many of which involve the actin cytoskeleton. Flightless I (Flii) is a highly conserved cytoskeletal protein, which has previously been identified as a potential target for improved healing of tendon injuries. Using human in vitro cell studies in conjunction with a murine model of partial laceration of the digital flexor tendon, we investigated the effect of modulating Flii levels on tenocyte function and formation of adhesions.
Human tenocyte proliferation and migration was determined using WST-1 and scratch wound assays following Flii knockdown by siRNA in vitro. Additionally, mice with normal and increased levels of Flii were subjected to a partial laceration of the digital flexor tendon in conjunction with a full tenotomy to immobilise the paw. Resulting adhesions were assessed using histology and immunohistochemistry for collagen I, III, TGF-β1and -β3 RESULTS: Flii knockdown significantly reduced human tenocyte proliferation and migration in vitro. Increasing the expression of Flii significantly reduced digital tendon adhesion formation in vivo which was confirmed through significantly smaller adhesion scores based on collagen fibre orientation, thickness, proximity to other fibres and crimping. Reduced adhesion formation was accompanied with significantly decreased deposition of type I collagen and increased expression of TGF-β1 in vivo.
These findings suggest that increasing the level of Flii in an injured tendon may be beneficial for decreasing tendon adhesion formation.
肌腱修复是常见的，但由于形成屈肌腱粘连，限制了受影响手指和手的活动度和使用，功能往往受限。粘连形成的严重程度取决于许多细胞过程，其中许多涉及肌动蛋白细胞骨架。无翅 I（Flii）是一种高度保守的细胞骨架蛋白，先前已被确定为改善肌腱损伤愈合的潜在靶标。我们使用人体外细胞研究结合数字屈肌腱部分撕裂的小鼠模型，研究了调节 Flii 水平对肌腱细胞功能和粘连形成的影响。
在体外通过 siRNA 敲低 Flii 后，使用 WST-1 和划痕实验测定人肌腱细胞的增殖和迁移。此外，正常和 Flii 水平升高的小鼠接受数字屈肌腱部分撕裂，并结合全肌腱切开术使爪子固定，以形成粘连。通过组织学和免疫组织化学评估胶原蛋白 I、III、TGF-β1 和 TGF-β3 来评估粘连。
Flii 敲低显著降低了人肌腱细胞的体外增殖和迁移。体内增加 Flii 的表达显著减少了数字肌腱粘连的形成，这通过基于胶原纤维取向、厚度、与其他纤维的接近程度和卷曲的更小粘连评分得到证实。粘连形成减少伴随着 I 型胶原蛋白沉积减少和 TGF-β1 的表达增加。
这些发现表明，在受伤的肌腱中增加 Flii 的水平可能有助于减少肌腱粘连的形成。
