An experimental osteoarthritis induced by implanting composite material into subchondral bone of rabbit knee / 中国矫形外科杂志

ABSTRACT

[Objective]To investigate the pathogenesis of osteoarthritis by increasing stiffness of subchondral bone to simulate subchondral bone sclerosis to induce the osteoarthritis.[Methods]The proportion between polymethylmethacrylate(PMMA),methylmethacrylate(MMA),hydroxyapatite(HA) and distilled water was adjusted to keep the maximum reaction temperature under 40℃.The composite material PMMA/HA was obtained and compressed on a mechanical material machine to determine its ultimate strength and stiffness,which were compared with those of subchondral bone.The subchondral bone of medial tibial plateau was scraped,where the composite material PMMA /HA was implanted into.Rabbits were sacrificed at 3,6,9 and 12 weeks,respectively.The articular cartilages of the medial tibial plateau were harvested for histological observation.Immunohistochemical analysis was adopted to record the expression and distribution of collagen type Ⅱ and MMP-1 in cartilage at protein level,which were compared with the blank and control groups.Transmission electron microscope was used to examine the ultramicroscopic changes of chondrocytes in blank and 6,12-week-postsurgery groups.[Results]With the time going,the experimental groups gradually presented degeneration,and had increased histological Mankin score.TEM demonstrated degenerative changes of chondrocytes.Collagen type Ⅱ expressed mainly in transition zone and upper deep zone,and MMP-1 expressed predominantly in the superficial and upper intermediate layers of cartilage.Both expressions steadily increased with time passing.[Conclusion]The increased stiffness of subchondral bone induced osteoarthritis in rabbits,which suggests that subcondral bone sclerosis may induce cartilage damage,and that subcondral bone sclerosis is one of the initial pathogenesis of osteoarthritis.