【摘要】 背景:骨关节炎是一种以关节软骨降解和软骨下骨硬化为主要病理改变的退行性关节疾病,骨细胞在软骨下骨硬化中的作用和机制尚不明确。目的:探讨负荷加重导致的小鼠膝骨关节炎软骨下骨的病理特点、骨矿化指标以及骨细胞形态学和骨硬化蛋白分泌水平的改变。方法:选取10周龄的C57BL/6雄性小鼠共20只,随机分为骨关节炎组与对照组,每组各10只。骨关节炎组全麻下行前交叉韧带横切术建立膝骨关节炎模型,对照组行假手术。术后4周处死小鼠并收取膝关节样本,分别进行苏木精-伊红染色、甲苯胺蓝染色及国际骨关节炎研究学会评分;Micro-CT评价软骨下骨松质和软骨下硬骨板的骨矿化密度及相对骨体积分数值;扫描电镜观察骨细胞及软骨下骨板的形态学改变;免疫组化染色检测SOST/sclerostin的表达变化。结果与结论:(1)苏木精-伊红染色、甲苯胺蓝染色显示前交叉韧带横切术后4周,小鼠膝关节软骨及软骨下骨均出现明显骨关节炎表型,国际骨关节炎研究学会评分增高(P <0.05);(2)Micro-CT结果显示,前交叉韧带横切术后4周,膝骨关节的软骨下骨松质和软骨下硬骨板区域骨矿化密度值减少(P <0.05),而相对骨体积分数值增高(P <0.05),提示骨关节炎软骨下骨硬化是由骨矿化密度的下降和骨体积分数增高形成的;(3)扫描电镜结果显示,骨关节炎组小鼠膝关节软骨下骨板中的骨细胞失去正常的形态和排列方式,软骨下骨板矿化沉积形态不规则;(4)免疫组化染色显示,骨关节炎组小鼠膝关节中SOST/sclerostin免疫组化染色阳性细胞数明显较少,提示骨细胞形态的改变可能和骨硬化蛋白分泌水平改变有关;(5)结果表明,骨关节炎早期软骨下骨硬化主要体现为骨矿化密度值减少、相对骨体积分数值增高以及软骨下骨微观形态的不规则改变;前交叉韧带横切诱导下,在骨关节炎早期骨细胞即出现明显形态和排列的改变,分泌骨硬化蛋白的量亦受到影响。更多还原

【Abstract】 BACKGROUND: Osteoarthritis is a degenerative joint disease, and the main pathological features are cartilage degradation and subchondral bone sclerosis. The function and mechanism of osteocytes in subchondral bone sclerosis remains unclear.OBJECTIVE: To investigate the pathological characteristics, changes in bone mineralization, morphological changes of osteocytes and expression changes of sclerostin in mice with overloading induced knee osteoarthritis.METHODS: Twenty 10-week-old male C57 BL/6 mice were randomly divided into osteoarthritis group and control group(n=10 per group). Anterior cruciate ligament transection was conducted to establish osteoarthritis models in the osteoarthritis group, and sham operation was carried out in the control group. Four weeks after operations, mice in each group were sacrificed. Knee samples collected were used for hematoxylin-eosin staining, toluidine blue staining and Osteoarthritis Research Society International(OARSI) scoring. Micro-CT was used to evaluate bone mineralization density and bone volume/trabecular volume of subchondral cancellous bone and subchondral lamina dura. Morphological changes of osteocytes and subchondral bone were observed using scanning electron microscope. Immunohistochemistry staining was used to detect SOST/sclerostin expression.RESULTS AND CONCLUSION: Hematoxylin-eosin staining and toluidine blue staining results showed that significant osteoarthritis phenotype was found in both articular cartilage and subchondral bone in the osteoarthritis group 4 weeks after anterior cruciate ligament transection, accompanied with increased OARSI scores(P < 0.05). Micro-CT scan results showed decreased bone mineralization density and increased bone volume/trabecular volume of subchondral cancellous bone and subchondral lamina dura 4 weeks after anterior cruciate ligament transection(P < 0.05), indicating that subchondral bone sclerosis consists of decreasing of bone mineralization density tissue and increasing of bone volume/trabecular volume. Under the scanning electron microscope, in the osteoarthritis group, normal morphology and arrangement of osteocytes were disturbed in the subchondral bone, while the morphology of mineralization of the subchondral bone was also distorted. Immunohistochemistry staining results showed that, compared with the control group, the number of sclerostin positive cells was significantly decreased in the osteoarthritis group, indicating the morphological changes of osteocytes may be related to changes in SOST/sclerostin expression. In conclusion, subchondral bone sclerosis in early osteoarthritis is mainly manifested as a decrease in bone mineralization density, an increase in bone volume/trabecular volume, and irregular changes in the microscopic morphology of the subchondral bone. After anterior cruciate ligament transection, significant changes in the morphological and arrangement of osteocytes are found in early osteoarthritis, and the secretion of sclerostin is also significantly changed.更多还原