Development of partial thickness articular cartilage injury in an ovine model

Abstract

The purpose of this study was to create a controlled partial thickness cartilage lesion in a sheep model, and to provide a foundation to study the natural history of the progression of this lesion. Twenty-eight sheep divided into four groups (1, 12, 24, and 52 weeks, n ¼ 7/group) were used in this study. In one stifle, a mechanical tool was used to create a 200 mm partial thickness lesion (1.5 Â 1.5 cm 2 ) on the medial femoral condyle via arthroscopy. Joint fluid was drawn presurgery and after euthanasia for analysis of collage II 3/4 C long (C2C). After euthanasia, the condyle was analyzed by gross appearance, confocal laser microscopy (CLM) for cell viability, scanning electronic microscopy (SEM) for surface roughness, Artscan for cartilage stiffness, and histology for cartilage morphology. The gross appearance of the treated area appeared rough, soft, and swollen compared to untreated control over time. CLM demonstrated that the depth of cell death increased to 590 mm at 52 weeks after surgery. SEM demonstrated that the treated area became more irregular over time. Stiffness of the treated area was significantly less than control by 12 weeks after surgery. Histologic analysis demonstrated that the 12, 24, and 52 week groups had significantly poorer histologic scores than the 1 week group. Joint fluid analysis demonstrated that the treatment group at 1 week had significant higher levels of C2C than the pretreatment baseline data. The results of this study demonstrated that partial thickness injury of cartilage continued to propagate and degenerate over time in this sheep model. Options for the prevention or treatment of this lesion may be tested using this model in the future. ß

Development of Partial-thickness Articular Cartilage Injury in a Rabbit Model

“…However, few studies have focused on alterations in cartilage surrounding a partial-thickness articular cartilage defect. Lu et al [18] reported ongoing degeneration of cartilage surrounding the defect in a sheep model during the course of 52 weeks. Because rabbits often are used as a model to test novel cartilage repair techniques, Hunziker and Quinn [14] reported a considerable number of chondrocytes were lost from cartilage adjacent to surgically created partial-thickness articular cartilage defects, whereas the synthetic activity of the remaining chondrocytes remained unchanged.…”

BMP‐7 protects against progression of cartilage degeneration after impact injury

“…This impact force was within or above the range of deleterious impact forces reported for intact joints or osteochondral segments in other animal species such as the rabbit 37,38 and bovine, 24 and the resulting injury was larger than a similar model that used partial thickness defects in this species. 39 Rabbits, or a laboratory animal model, may have been more convenient and allowed larger group sizes for these studies, but the mechanism of action for BMP-7 includes some aspects of improved cartilage repair; therefore, we were reluctant to use a species such as the rabbit that retains intrinsic repair capacity in adulthood. 40 The large body weight, flock behaviors, and housing conditions of these sheep ensured that traumatic injuries would receive regular loading to make partial thickness cartilage injuries progress.…”

Artroscopia do joelho de ovinos

“…No presente experimento o artroscópio foi inserido por acesso craniolateral realizado na altura da eminência do platô tibial e lateral ao ligamento patelar, e portal instrumental medial ao ligamento patelar e na altura do portal craniolateral. Outros experimentos com ovinos também inseriram o artroscópio por acesso lateral e demais instrumentais de apoio pelo acesso medial, sendo que um utilizou o artroscópio para avaliar o efeito da radiofreqüência monopolar em defeitos cartilaginosos da tróclea femoral (Lu et al 2000) e outro para induzir uma lesão na superfície central do côndilo medial (Lu et al 2006).…”

“…Os ovinos apresentam um grande coxim adiposo infrapatelar que preenche a porção dorsal do espaço articular femorotibial, unindo e obscurecendo o ligamento cruzado cranial (Allen et al 1998). Sendo assim, da mesma forma que em cães, faz-se necessária a remoção da gordura infrapatelar, a fim de criar um espaço maior para visibilizar as estruturas (Ryssen et al 2003, Tatarunas & Matera 2004, Lu et al 2006.…”

“…Visto o número limitado de trabalhos experimentais que utilizaram o exame artroscópico em ovinos (Dürselen et al 1996, Lu et al 2000, Szomor et al 2000, Lu et al 2006) e a importância desses animais como modelo experimental, o presente trabalho teve por objetivo avaliar a articulação do joelho de ovinos hígidos em diferentes idades, com o intuito de determinar, de acordo com os portais estabelecidos, a capacidade de observação das estruturas.…”