Objective: To study the expression difference of Sclerostin in the medial and lateral subchondral bone of the varus osteoarthritic knee plateau.
Methods: The tibial plateau was obtained from 20 patients with varus knee osteoarthritis receiving total knee arthroplasty from March to October 2015. There were 8 males and 12 females with an average age of 67.8 years (range, 61-78 years). The mean course of osteoarthritis was 3.2 years (range, 2-5 years). Before operation, the varus angle was 12.0-25.5° (mean, 17.6°) on the X-ray film. Five cases were rated as grade III and 15 cases as grade IV according to Kellgren-Lawrance classification. Micro-CT scan was performed on the medial and lateral subchondral bone to compare the changes of bone structure; bone volume/total volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), structure model index (SMI), and the trabecular separation (Tb.Sp) were measured. Immunohistochemistry and real-time fluorescent quantitative PCR were used to test the expressions of Sclerostin protein and sost gene.
Results: Micro-CT showed that BV/TV, Tb.N, and Tb.Th significantly increased in the medial subchondral bone when compared with the lateral part ( P<0.05), but SMI and Tb.Sp significantly reduced ( P<0.05). Real-time fluorescent quantitative PCR detection showed that sost gene expression level in the medial subchondral bone (1.000) was significantly lower than that in the lateral part (4.157±2.790) ( t=2.371, P=0.040). The percentage of Sclerostin positive cells in the lateral subchondral bone (52.00%±0.19%) was significantly higher than that in the medial subchondral bone (7.20%±0.04%) ( t=5.094, P=0.005).
Conclusion: Sclerostin plays an important role in the subchondral bone remodeling of the varus osteoarthritic knee. And the low expression of Sclerostin may be an important factor to promote bone remodeling and aggravate knee deformity.
目的: 比较内翻畸形膝关节骨关节炎内、外侧胫骨平台软骨下骨中硬化蛋白表达差异，探讨其发生机制及意义。.
方法: 取 2015 年 3 月—10 月 20 例接受人工全膝关节置换术的内翻畸形膝关节骨关节炎患者自愿捐赠的胫骨平台标本。其中，男 8 例，女 12 例；年龄 61～78 岁，平均 67.8 岁。病程 2～5 年，平均 3.2 年。术前均摄膝关节 X 线片，测量内翻角为 12.0～25.5°，平均 17.6°；Kellgren-Lawrance 分级：Ⅲ级 5 例、Ⅳ级 15 例，均以内侧间室病变为主。取内、外侧胫骨平台软骨下骨行 Micro-CT 检查，比较骨结构变化差异；测量骨体积分数（bone volume/total volume，BV/TV）、骨小梁数量（trabecular number，Tb.N）、骨小梁厚度（trabecular thickness，Tb.Th）、结构模型指数（structure model index，SMI）、骨小梁分离度（trabecular separation，Tb.Sp）；行免疫组织化学染色及实时荧光定量 PCR 检测硬化蛋白以及 sost 基因表达水平。.
结果: Micro-CT 显示，与外侧软骨下骨相比，内侧软骨下骨骨量增加，孔隙减少；内侧软骨下骨 BV/TV、Tb.N、Tb.Th 较外侧显著增高，SMI、Tb.Sp 较外侧显著降低，比较差异均有统计学意义（ P<0.05）。实时荧光定量 PCR 检测，内侧胫骨平台软骨下骨中 sost 基因表达为 1.000，外侧为 4.157±2.790，比较差异有统计学意义（ t=2.371， P=0.040）。内侧软骨下骨中硬化蛋白表达阳性细胞所占百分比为 7.20%±0.04%，较外侧软骨下骨（52.00%±0.19%）显著降低，比较差异有统计学意义（ t=5.094， P=0.005）。.
结论: 内翻畸形膝关节骨关节炎患者的内侧胫骨平台软骨下骨成骨增加，硬化蛋白表达降低可能是促进骨重塑、加重膝内翻畸形的一个重要因素。.
Keywords: Osteoarthritis; Sclerostin; bone remodeling; subchondral bone.