软骨下骨量变化与软骨退变的相关性

Correlation between subchondral bone mass and cartilage degeneration

背景:关节软骨与软骨下骨在骨关节炎病变进程中的相互作用机制目前尚未完全阐明。软骨下骨量改变在骨关节炎病理进程中亦发挥重要作用。目的:分析2种手术方式及2种蛋白酶诱导建立兔膝关节骨关节炎动物模型的效果,以及软骨下骨量变化与关节软骨退变的相关性。方法:32只新西兰大白兔随机分为4组:Hulth模型组、前交叉韧带切断模型组、Ⅱ型胶原蛋白酶组及木瓜蛋白酶组,每组8只,右膝关节造模,左膝关节作为自身对照。造模后0,4,8周行DXA扫描,8周行MRI扫描后处死实验动物,取双侧膝关节制作病理组织学切片,比较各组膝关节影像学表现、大体形态及病理变化,并采用Mankin评分进行定量分析。结果与结论:造模后0,4,8周实验侧膝关节骨密度进行性降低,骨量降低程度Hulth模型组>前交叉韧带切断模型组>Ⅱ型胶原蛋白酶组>木瓜蛋白酶组。MRI显示实验侧股骨内外髁关节软骨厚度变薄,厚度Hulth模型组<前交叉韧带切断模型组<Ⅱ型胶原蛋白酶组<木瓜蛋白酶组。大体标本、组织切片观察及Mankin评分显示手术建模组骨关节炎程度较药物组重,Hulth模型组病变最重,木瓜蛋白酶组最轻。结果说明关节内手术及关节腔内注射蛋白酶均能建立骨关节炎动物模型;手术造模可复制出中晚期骨关节炎,药物诱导可产生骨关节炎早期改变。骨关节炎病变严重程度与软骨下骨骨密度呈负相关;关节软骨退变和软骨下骨改变相互关联,病变进行性发展。

BACKGROUND：Correlation between subchondral bone and articular cartilage in the process of osteoarthritis has not been fuly elucidated. Degeneration of cartilage is the focus of attention, and the subchondral bone also plays an important role in the process of osteoarthritis. OBJECTIVE： To observe the differences between experimental osteoarthritis models in rabbit knees established by two kinds of surgical methods and two kinds of proteases inducing methods, and to explore the correlation between subchondral bone mass and degeneration of cartilage. METHODS：Thirty-two New Zealand rabbits were randomly and averagely divided into four groups： Hulth group （group A）, anterior cruciate ligament transaction group （group B）, colagenase type II group （group C） and papain group （group D）. The right knees of rabbits were established as osteoarthritis models, and the left knees served as controls. Bone mineral density of the knee joint was evaluated by dual-energy X-ray absorptiometry scanning at 0, 4 and 8 weeks after modeling. The rabbits were sacrificed at 8 weeks after MRI scanning, bilateral knee joints were harvested for general and histological observation. Quantitative analysis was done according to Mankin scores. RESULTS AND CONCLUSION： Bone mineral density of the right knees decreased at 0, 4 and 8 weeks after modeling, and the rank was as folows： group A 〉 group B 〉 group C 〉 group D. MRI scanning showed that the articular cartilage thickness of the medial and lateral femoral condyle on the right knees became thinner compared with the left side, and the rank was as folows： group A 〈 group B 〈 group C 〈 group D. Observation by specimens and pathological slices showed that the articular cartilage degeneration of the surgery groups worsened, group A was the most serious one, and group 1D was the lightest. Both surgery and proteases inducing methods can successfuly establish osteoarthritis models in rabbit knees. Surgery inducing models resemble the advanced or intermediate stage of osteoarthritis, while the proteases inducing models resemble the early stage of osteoarthritis. Degeneration of the articular cartilage and changes of subchondral bone are related in progressive development.