Chronological changes in the collagen-type composition at tendon–bone interface in rabbits

Abstract

ObjectivesThe purpose of this study was to evaluate chronological changes in the collagen-type composition at tendon–bone interface during tendon–bone healing and to clarify the continuity between Sharpey-like fibres and inner fibres of the tendon.MethodsMale white rabbits were used to create an extra-articular bone–tendon graft model by grafting the extensor digitorum longus into a bone tunnel. Three rabbits were killed at two, four, eight, 12 and 26 weeks post-operatively. Elastica van Gieson staining was used to colour 5 µm coronal sections, which were examined under optical and polarised light microscopy. Immunostaining for type I, II and III collagen was also performed.ResultsSharpey-like fibres comprised of type III collagen in the early phase were gradually replaced by type I collagen from 12 weeks onwards, until continuity between the Sharpey-like fibres and inner fibres of the tendon was achieved by 26 weeks.ConclusionsEven in rabbits, which heal faster than humans, an observation period of at least 12 to 26 weeks is required, because the collagen-type composition of the Sharpey-like fibre bone–tendon connection may have insufficient pullout strength during this period. These results suggest that caution is necessary when permitting post-operative activity in humans who have undergone intra-bone tunnel grafts.

Mechano-regulation of collagen biosynthesis in periodontal ligament

“…Increases in type III collagen were observed in early phases of wound healing and were eventually replaced with type I collagen [118]. In particular, in the early healing process, Sharpey’s fiber-like structure in the tendon-bone interface express type III collagen [119-121]. Furthermore, increases in type III collagen expression in response to mechanical loading has been reported in dermal fibroblasts , mesenchymal stem cells [122], anterior crucial ligament cells [123] and medial collateral ligament [124].…”

Dual-layer aligned-random nanofibrous scaffolds for improving gradient microstructure of tendon-to-bone healing in a rabbit extra-articular model

“…Several studies have reported that indirect connection, mostly consisting of Sharpey's-like fibers, was observed in the healing process of different tendon-bone models. [7][8][9] Nevertheless, this indirect connection with poorly organized fibers between the tendon and the bone was far from the native structure and had insufficient pullout strength. As a result, the inferior mechanical and biochemical properties of the repaired tissue could increase the risk of reinjury and continued disability.…”

Hamstring Graft Biological Preparation for Anterior Cruciate Ligament Reconstruction

“…5,6 The amount of these fibers gradually increases over time, and their major constituent changes from type III to type I collagen. 7 They are not, however, uniformly present at all the bone tunnel interfaces until the final stage. 8 Bone ingrowth will occur into the formed fibrous interface tissue throughout osteointegration.…”