The Changes of Stifle Joint Fluid with Cranial Cruciate Ligament Rupture in Dogs

To determine whether localization of tartrate-resistant acid phosphatase (TRAP) and cathepsin K was associated with rupture of the cranial cruciate ligament (CCL) in dogs. Tissue specimens were obtained from 30 dogs with CCL rupture during surgical treatment, 8 aged normal dogs, and 9 young normal dogs that were necropsied for reasons unrelated to this study and unrelated to musculoskeletal disease. The cranial cruciate ligament was examined histologically. $TRAP^+$ cells and cathepsin $K^+$ cells were identified by histochemical staining and immunohistochemical staining respectively. TRAP and cathepsin $K^+$ were co-localized within the same cells principally located within the epiligamentous region and to a lesser extent in the core region of ruptured CCL. Localization of $TRAP^+$ cells (P < 0.05) and cathepsin $K^+$ cells (P =0.05) within CCL tissue was significantly increased in dogs with CCL rupture, compared with aged-normal dogs, and young normal dogs (P < 0.05 - TRAP, P < 0.001 - cathepsin K). Localization of $TRAP^+$ cells and cathepsin $K^+$ cells within the CCL tissue of aged-normal dogs was also increased compared with young normal dogs (P < 0.05). Small numbers of $TRAP^+$ cells and cathepsin $K^+$ cells were seen in the intact ligaments of aged-normal dogs, which were associated with ligament fasicles in which there was chondroid transformation of ligament fibroblasts and disruption of the organized hierarchical structure of the extracellular matrix. $TRAP^+$ cells and cathepsin $K^+$ cells were not seen in CCL tissue from young-normal dogs. Localization of the proteinases $TRAP^+$ and cathepsin $K^+$ in CCL tissue was significantly associated with CCL rupture. Small numbers of proteinase positive cells were also localized in the CCL of agednormal dogs without CCL rupture, but were not detected in CCL from young-normal dogs. Taken together, these findings suggest that the cell signaling pathways that regulate expression of these proteinases in CCL tissue may form part of the mechanism that leads to upregulation of collagenolytic ligament remodeling and progressive structural failure of the CCL over time.

개에 있어서 전방십자인대 단열시 슬관절액의 변화

본 연구는 전십자인대가 단열된 개의 슬관절액에서 tartrate-resistant acid phosphatase (TRAP) 와 cathepsin K의 변화를 알아봄으로서 십자인대에 관련된 질병 또는 십자인대 치료 실패에 따른 퇴행성관절염의의 조기 진단 및 치료에 관한 정보를 얻기 위하여 실시하였다. 실험동물로는 전방십자인대가 단열된 30두의 개와 정상 성견 8 두 그리고 어린 정상 개 9두를 사용하였다. 슬관절액 내의 TRAP 과 Cathepsin K의 변화를 확인하기 위하여 조직화학 염색과 면역조직화학염색을 실시하였다. 조직학적인 검사 결과 정상견에서는 TRAP과 Cathepsin K 세포들은 찾아보기 힘들었으나 전방십자인대가 단열된 개에 있어서는 TRAP 과 Cathepsin K 그리고 chondroid metaplasia가 중심부분에서 증가되고 있음을 관찰하였다. 이러한 결과로 보아 TRAP과 Cathepsin K 세포들은 전방십자인대가 단열 또는 단열 후 회복되는 과정에서 상호 보조적으로 관여하며 세포외 방출과 관계가 있는 것으로 생각된다.