title: Spatial and temporal changes of subchondral bone proceed to articular cartilage degeneration in rats subjected to knee immobilization.
abstract: This study was aimed to investigate the spatial and temporal changes of subchondral bone and its overlying articular cartilage in rats following knee immobilization. A total of 36 male Wistar rats (11-13 months old) were assigned randomly and evenly into 3 groups. For each group, knee joints in 6 rats were immobilized unilaterally for 1, 4, or 8 weeks, respectively, while the remaining rats were allowed free activity and served as external control groups. For each animal, femurs at both sides were dissected after sacrificed. The distal part of femur was examined by micro-CT. Subsequently, femoral condyles were collected for further histological observation and analysis. For articular cartilage, significant changes were observed only at 4 and 8 weeks of immobilization. The thickness of articular cartilage and chondrocytes numbers decreased with time. However, significant changes in subchondral bone were defined by micro-CT following immobilization in a time-dependent manner. Immobilization led to a thinner and more porous subchondral bone plate, as well as a reduction in trabecular thickness and separation with a more rod-like architecture. Changes in subchondral bone occurred earlier than in articular cartilage. More importantly, immobilization-induced changes in subchondral bone may contribute, at least partially, to changes in its overlying articular cartilage.
authors.affiliation: Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, 1838 Guangzhou Avenue (N), Guangzhou, 510515, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, 1838 Guangzhou Avenue (N), Guangzhou, 510515, China.|Department of Orthopedics, Zhengzhou Orthopedics Hospital, 58 Longhai Road, Zhengzhou, 450052, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Rehabilitation Medicine, Longyan First Hospital, 105 Jiuyi Road (N), Longyan, 364000, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Lei
authors.affiliation: Department of Rehabilitation Medicine, First Affiliated Hospital, Fujian Medical University, 20 Chazhong Road, Fuzhou, 350005, China.
authors.forename: Yue-Zhu
authors.initials: YZ
authors.lastname: Zhou
authors.affiliation: Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, 1838 Guangzhou Avenue (N), Guangzhou, 510515, China.
authors.forename: Song-Yun
authors.initials: SY
authors.lastname: Deng
authors.affiliation: Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, 1838 Guangzhou Avenue (N), Guangzhou, 510515, China.
authors.forename: Yong-Bin
authors.initials: YB
authors.lastname: He
authors.affiliation: Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, 1838 Guangzhou Avenue (N), Guangzhou, 510515, China.|Department of Rehabilitation Medicine, First Affiliated Hospital, Fujian Medical University, 20 Chazhong Road, Fuzhou, 350005, China.
authors.forename: Guo-Xin
authors.initials: GX
authors.lastname: Ni
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000473:pathology*; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology*; D006652:Histological Techniques; D007103:Immobilization / Q000009:adverse effects*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013264:Stifle / Q000000981:diagnostic imaging / Q000473:pathology*; D055114:X-Ray Microtomography
keywords: cartilage; immobilization; subchondral bone