title: Effect of gradual weight-bearing on regenerated articular cartilage after joint distraction and motion in a rabbit model.
abstract: The purpose of this study was to clarify the effect of gradual weight bearing (GWB) on regenerating cartilage. We developed a novel external fixation device (EFD) with a controllable weight-bearing system and continuous passive motion (CPM). A full-thickness defect was created by resection of the entire articular surface of the tibial plateau after the EFD was fixed in the rabbit's left knee. In the GWB group (n=6), GWB was started 6 weeks after surgery. In the CPM group (n=6), CPM with EFD was applied in the same manner without GWB. The control group (n=5) received only joint distraction. All rabbits were sacrificed 9 weeks after surgery. The central one-third of the regenerated tissue was assessed and scored blindly using a grading scale modified from the International Cartilage Repair Society visual histological assessment scale. The areas stained by Safranin-O and type II collagen antibody were measured, and the percentage of each area was calculated. There was no significant difference in the histological assessment scale among the groups. The percentage of the type II collagen-positive area was significantly larger in the GWB group than in the CPM group. The present study suggests that optimal mechanical stress, such as GWB, may affect regeneration of cartilage, in vivo.
authors.affiliation: University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan. CZI12265@nifty.com
authors.forename: Tomofumi
authors.initials: T
authors.lastname: Nishino
authors.forename: Tomoo
authors.initials: T
authors.lastname: Ishii
authors.forename: Fei
authors.initials: F
authors.lastname: Chang
authors.forename: Takaji
authors.initials: T
authors.lastname: Yanai
authors.forename: Arata
authors.initials: A
authors.lastname: Watanabe
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ogawa
authors.forename: Hajime
authors.initials: H
authors.lastname: Mishima
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Nakai
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Ochiai
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology / Q000502:physiology / Q000601:surgery*; D019245:Compressive Strength / Q000502:physiology; D016267:External Fixators; D007202:Indicators and Reagents; D007719:Knee Joint / Q000502:physiology / Q000601:surgery*; D023421:Models, Animal; D009068:Movement / Q000502:physiology*; D019857:Osteogenesis, Distraction / Q000295:instrumentation / Q000379:methods*; D010619:Phenazines; D011312:Pressure; D011817:Rabbits; D012038:Regeneration / Q000502:physiology*; D012394:Rosaniline Dyes; D013977:Tibia / Q000502:physiology / Q000601:surgery; D016474:Weight-Bearing / Q000502:physiology*
chemical_list: D007202:Indicators and Reagents; D010619:Phenazines; D012394:Rosaniline Dyes; C035906:Fast Green; C009195:safranine T