title: Degenerative changes of the cranial cruciate ligament harvested from dogs with cranial cruciate ligament rupture.
abstract: Degenerative cranial cruciate ligament (CCL) rupture is characterized histologically by degenerating extracellular matrix (ECM) and chondroid metaplasia. Here, we describe the progression of chondroid metaplasia and the changes in the expression of ECM components in canine CCL rupture (CCLR). CCLs from 26 stifle joints with CCLR (CCLR group) and normal CCLs from 12 young beagles (control group) were examined histologically and immunohistochemically for expression of type I (COLI), type II (COLII), type III collagen (COLIII) and Sry-type HMG box 9 (SOX9). Cell density and morphology of CCLs were quantified using hematoxylin-eosin staining. The percentage of round cells was higher in the CCLR group than in controls. COLI-positive areas were seen extensively in the connecting fibers, but weakly represented in the cytoplasm of normal CCLs. In the CCLR group, there were fewer COLI-positive areas, but many COLI-positive cells. The percentages of COLII-, COLIII- and SOX9-positive cells were higher in the CCLR group than in controls. The number of spindle cells with perinuclear halo was high in the CCLR group, and most of these cells were SOX9-positive. Deposition of COLI, the main ECM component of ligaments, decreased with increased COLIII expression in degenerated CCL tissue, which shows that the deposition of the ECM is changed in CCLR. On the contrary, expression of SOX9 increased, which may contribute to the synthesis of cartilage matrix. The expression of COLII and SOX9 in ligamentocytes showed that these cells tend to differentiate into chondrocytes.
authors.affiliation: The Laboratory of Veterinary Surgery, Nippon Veterinary and Life Science University, 1-7-1 Kyounan, Musashino, Tokyo 180-8602, Japan.
authors.forename: Tom
authors.initials: T
authors.lastname: Ichinohe
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kanno
authors.forename: Yasuji
authors.initials: Y
authors.lastname: Harada
authors.forename: Takuya
authors.initials: T
authors.lastname: Yogo
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tagawa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Soeta
authors.forename: Hajime
authors.initials: H
authors.lastname: Amasaki
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Hara
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000737:chemistry / Q000473:pathology*; D002452:Cell Count / Q000662:veterinary; D024042:Collagen Type I / Q000032:analysis; D024043:Collagen Type II / Q000032:analysis; D024061:Collagen Type III / Q000032:analysis; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs / Q000293:injuries; D005260:Female; D008297:Male; D012422:Rupture, Spontaneous / Q000473:pathology / Q000662:veterinary; D055758:SOX9 Transcription Factor / Q000032:analysis
chemical_list: D024042:Collagen Type I; D024043:Collagen Type II; D024061:Collagen Type III; D055758:SOX9 Transcription Factor