title: Controlling joint instability delays the degeneration of articular cartilage in a rat model.
abstract: Joint instability induced by anterior cruciate ligament (ACL) transection is commonly considered as a predisposing factor for osteoarthritis (OA) of the knee; however, the influence of re-stabilization on the protection of articular cartilage is unclear. The aim of this study was to evaluate the effect of joint re-stabilization on articular cartilage using an instability and re-stabilization ACL transection model.
  
  
  
  To induce different models of joint instability, our laboratory created a controlled abnormal joint movement (CAJM) group and an anterior cruciate ligament transection group (ACL-T). Seventy-five Wistar male rats were randomly assigned to the CAJM (n = 30), ACL-T (n = 30), or no treatment (INTACT) group (n = 15). Cartilage changes were assessed with soft X-ray analysis, histological and immunohistochemistry analysis, and real-time polymerase chain reaction (PCR) analysis at 2, 4, and 12 weeks.
  
  
  
  Joint instability, as indicated by the difference in anterior displacement between the CAJM and ACL-T groups (P < 0.001), and cartilage degeneration, as evaluated according to the Osteoarthritis Research Society International (OARSI) score, were significantly higher in the ACL-T group than the CAJM group at 12 weeks (P < 0.001). Moreover, joint re-stabilization maintained cartilage structure (thickness [P < 0.001], surface roughness [P < 0.001], and glycosaminoglycan stainability [P < 0.001]) and suppressed tumor necrosis factor-alpha (TNF-α) and caspase-3 at 4 weeks after surgery.
  
  
  
  Re-stabilization of joint instability may suppress inflammatory cytokines, thereby delaying the progression of OA. Joint instability is a substantial contributor to cartilage degeneration.
authors.affiliation: Graduate Course of Health and Social Services, Graduate School of Saitama Prefectural University, Saitama, Japan; Department of Physical Therapy, School of Health and Social Services, Saitama Prefectural University, Saitama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Murata
authors.affiliation: Department of Physical Therapy, School of Health and Social Services, Saitama Prefectural University, Saitama, Japan. Electronic address: kanemura-naohiko@spu.ac.jp.
authors.forename: N
authors.initials: N
authors.lastname: Kanemura
authors.affiliation: Department of Physical Therapy, School of Health and Social Services, Saitama Prefectural University, Saitama, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kokubun
authors.affiliation: Graduate Course of Health and Social Services, Graduate School of Saitama Prefectural University, Saitama, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Fujino
authors.affiliation: Graduate Course of Health and Social Services, Graduate School of Saitama Prefectural University, Saitama, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Morishita
authors.affiliation: Graduate Course of Health and Social Services, Graduate School of Saitama Prefectural University, Saitama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Onitsuka
authors.affiliation: Graduate Course of Health and Social Services, Graduate School of Saitama Prefectural University, Saitama, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Fujiwara
authors.affiliation: Graduate Course of Health and Social Services, Graduate School of Saitama Prefectural University, Saitama, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Nakajima
authors.affiliation: Department of Physical Therapy, School of Health and Social Services, Saitama Prefectural University, Saitama, Japan.
authors.forename: D
authors.initials: D
authors.lastname: Shimizu
authors.affiliation: Department of Physical Therapy, School of Health and Social Services, Saitama Prefectural University, Saitama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Takayanagi
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000473:pathology; D002358:Cartilage, Articular / Q000473:pathology*; D004195:Disease Models, Animal; D007593:Joint Instability / Q000150:complications / Q000517:prevention & control*; D008297:Male; D020370:Osteoarthritis, Knee / Q000209:etiology / Q000517:prevention & control; D051381:Rats; D017208:Rats, Wistar
keywords: Articular cartilage; Caspase-3; Joint instability; Osteoarthritis; Tumor necrosis factor alpha