The Distribution of Types I and III Collagen and Fibronectin in the Healing Equine Tendon

The purpose of this study is to observe type I and type 111 procollagen gene expressions in the healing ligament using in situ hybridization histochemistry. The rabbit medial collateral ligaments were incised and harvested at 3, 7, 14, and 28 days postoperatively. The healing ligament showed increased expression of both procollagen genes through this period compared with the unoperated ligament. The peak expression level was observed at 7 or 14 days for type I and at 7 days for type 111, respectively. The strongest expression of both genes was detected in the scar tissue created between the ends of the old ligament. Although type 111 procollagen gene expression was observed almost only in the newly created scar tissue, type I procollagen gene was expressed not only in the scar tissue, but also at the ends of the previously normal ligament. These results suggest that type I collagen synthesis begins shortly after ligament injury and occurs at the ends of the injured ligament as well as in the scar tissue, and that type 111 collagen is largely synthesized in the scar tissue around one week after injury but continues being synthesized for at least four weeks after injury. 0 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. lntroduction Materials and methods Animals und treatmentCollagen is the most abundant substance in the norma1 ligament [7], and the mechanical properties of ligInstitutional Review Board Approval was obtained before beginning all animal studies. Twenty adult Japanese white rabbits, weighing ament depend primarily On ' ' ' lagen fibers L1 51' 3.24.4 kg, were used. Each animal was anesthetized with an intraveTherefore, collagen synthesis plays an important role in nous injection of pentobarbital. The medial collateral ligament (MCL) the healing process of the ruptured ligament. In the of the left knee was exposed through longitudinal medial incisions in the skin and fascia [6j. The MCL was cut transversely at the level of the suprameniscal recess with a scalpel [16]. Ligament ends were allowed to with less than lo'% being type I11 [7]. Although the retract and were not repaired surgically. Skin was approximated with healing ligament is known to contain an increased 3-0 nylon sutures. NO immobilization was used after surgery.With a lethal injection of a euthanasia solution, the animals were

Section: Discussionsupporting

confidence: 91%

Type I and type III procollagen gene expressions in the early phase of ligament healing in rabbits: an in situ hybridization study

Sakai

Koibuchi

Ohtake

et al. 2001

“…The tendons in group B appeared macroscopically normal but had a significant increase in fibroiiectin content compared with group A, but not compared with the controls, which may be due to the low number of controls. In this study, as well as in other studies [1, 3,6,16], fibronectin was also shown to be present in normal endotenon. Before fibronectin possibly could serve as a marker for early tendon damage further investigations are necessary.…”

Section: B Tillcinder Rt Ul I Journui Of' Orthilpuedic Rrsrurch 19 supporting

confidence: 67%

Carrageenan‐induced subacromial bursitis caused changes in the rat's rotator cuff

Tillander

Franzén

Nilsson

et al. 2001

ibstractThis study was designed to investigate the histologic expression of the rat's supra-and infraspinatus tendons in carrageenannduced subacromial bursitis. Thirty-two rats received subacromial injections with carrageenan ( n = 28) or saline ( n = 4). The endons were analysed microscopically after staining with hematoxyline eosin, Van Giesons hematoxyline and immunofluorescent itaining of fibronectin and fibrinogen. In the controls (saline x 10) and group A (carrageenan x 5 ) there were no changes in the endons. In group B (carrageenan x 10) 3/8 rats showed macrophages between the collagen fibres and an increased staining of ibronectin. In group C (double dosis carrageenan) all rats had signs of fibrocartilaginous metaplasia in the supraspinatus endon. In eight of these specimens even bony metaplasia was seen. The infraspinatus tendon showed fibrosis but no fibro-:artilaginous metaplasia. The results showed that iatrogenic bursitis after carrageenan subacromial injections was associated with narked changes of the supraspinatus tendon.

“…20,22,25,[41][42][43][44][45] The use of this technique to create a suitable model for the study of naturally occurring tendinitis has been supported by the evaluation of gross and histopathological changes, clinical signs, and ultrasonographic findings following the induction of injury. 44,[46][47][48] In addition, our laboratory has successfully investigated the effects of recombinant IGF-I on equine tendon healing using this collagenase induced model of tendinitis. 20 The histologic, biochemical, and mechanical characteristics of the injured tendons in this study are consistent with those described in previous reports using the collagenase induced model.…”

Section: Discussionmentioning

confidence: 99%

Mesenchymal stem cells and insulin‐like growth factor‐I gene‐enhanced mesenchymal stem cells improve structural aspects of healing in equine flexor digitorum superficialis tendons

Schnabel

Lynch

Meulen

et al. 2009

225

206

Tendinitis remains a catastrophic injury among athletes. Mesenchymal stem cells (MSCs) have recently been investigated for use in the treatment of tendinitis. Previous work has demonstrated the value of insulin-like growth factor-I (IGF-I) to stimulate cellular proliferation and tendon fiber deposition in the core lesion of tendinitis. This study examined the effects of MSCs, as well as IGF-I geneenhanced MSCs (AdIGF-MSCs) on tendon healing in vivo. Collagenase-induced bilateral tendinitis lesions were created in equine flexor digitorum superficialis tendons (SDFT). Tendons were treated with 10 Â 10 6 MSCs or 10 Â 10 6 AdIGF-MSCs. Control limbs were injected with 1 mL of phosphate-buffered saline (PBS). Ultrasound examinations were performed at t ¼ 0, 2, 4, 6, and 8 weeks. Horses were euthanized at 8 weeks and SDFTs were mechanically tested to failure and evaluated for biochemical composition and histologic characteristics. Expression of collagen types I and III, IGF-I, cartilage oligomeric matrix protein (COMP), matrix metalloproteinase-3 (MMP-3), matrix metalloproteinase-13 (MMP-13), and aggrecanase-1 (ADAMTS-4) were similar in MSC and control tendons. Both MSC and AdIGF-MSC injection resulted in significantly improved tendon histological scores. These findings indicate a benefit to the use of MSCs and AdIGF-MSCs for the treatment of tendinitis. ß