糖皮质激素对膝关节周围成骨细胞一氧化氮合酶和骨重建的影响

目的研究糖皮质激素对膝关节成骨细胞一氧化氮合酶表达和软骨下骨质重建的影响。方法取健康SD大鼠24只，体重（0．45±0．02）kg，随机分为实验组（A组）和对照组（B组），每组12只。实验组每周一次左膝关节腔内注射复方倍他米松0．02ml／kg，对照组每周一次左膝关节腔内注射生理盐水0．02ml／kg。4周时对两组大鼠的左侧膝关节股骨成骨细胞的诱生型一氧化氮合酶（inducible nitric oxide synthase，iNOS）和内皮细胞型一氧化氮合酶（endothelial nitric oxide synthase，eNOS）免疫组织化学研究，测定其平均灰度值和平均积分光密度，同时进行左胫骨软骨下骨质显微结构观察。结果实验组和对照组iNOS免疫组化的结果均为阴性，实验组eNOS的表达显著低于对照组（P〈0．01），实验组左胫骨的软骨下骨质旱骨质疏松特征。结论糖皮质激素对膝关节成骨细胞内皮细胞型一氧化氮合酶的表达和软骨下骨质生成有明显的抑制作用。

Effects of glucocorticoid on nitric oxide synthase of osteoblast and bone remodeling around the knee joint

Objective To study the effectiveness of glucocorticoid on nitric oxide synthase of osteoblast and bone remodeling around the knee joint. Methods Twenty-four SD rats, weighted （0.45±0.02 ） kg each, were randomly divided into 2 groups （12 rats for each group）. Group A, given compound betamethasone 0.02 ml/kg through injection into left knee joint. Group B, given 0.9% natrium chloride 0.02 ml/kg through injection into left knee joint. After the experiment lasted for 4 weeks, immunohistochemistry was used to study the expression of inducible nitric oxide synthase and endothelial nitric oxide synthase and the image analysis was done to measure their grayscale and average integral optical density. At the same time, the structure of bone trabeculae of the tibias of all the rats were observed. Results No significant defference was observed in the expression of iNOS between the two groups. The expression of eNOS in group A significantly decreased, compard to that of group B （P〈0.01）. The structure of tibias of group A presented the feature of osteoporosis. Conclusion Compound betamethasone decreases the the expression of eNOS in osteoblast and results in the lower amount of bone formation around the knee joint.