中文摘要：

目的：比较两种不同强度脉冲电磁场（pulsed electromagnetic fields，PEMFs）对大鼠膝关节骨性关节炎（osteoarthritis，OA）软骨和软骨下骨结构的影响。方法：40只成年雄性SD大鼠随机平均分为4组：0．8mTPEMFs组，1．6mTPEMFs组，OA组和正常对照（normalcontrol，NC）组。两PEMFs组及OA组大鼠右膝关节接受0．2mg碘乙酸钠注射，建立OA模型。4周后，两PEMFs组接受频率为75Hz，强度为0．8roT或1．6mT，2小时／天，4周的PEMFs治疗。采用甲苯胺蓝染色OARSI评分和显微CT技术分析软骨和软骨下骨结构。结果：组织学观察发现，与OA组相比，两PEMFs组软骨表层相对完整，轻度纤维化，潮线清晰。OARSI评分显示，两PEMFs组与OA组OARSI评分无显著性差异（P〉0．05）。显微CT发现与OA组比较，1．6mTPEMFs组骨小梁数量增多，骨小梁分离度降低，0．8mTPEMFs组骨小梁厚度和骨体积分数降低，骨小梁数量和骨表面积与体积比升高，差异有显著性意义（P〈0．05）。两PEMFs组之间无显著性差异（P〉0．05）。结论：PEMFs可能对大鼠膝OA软骨和软骨下骨结构有保护作用，但1．6mT和0．8mT强度的PEMFs治疗效果没有明显差异。

英文摘要：

To investigate the efficacy of different intensity pulsed electromagnetic fields （PEMFs） on the struc- ture of cartilage and subchondral bone in knee osteoarthritis （OA） rat. Method： Forty SD rats were randomly assigned to four groups： 0.8mT PEMFs group, 1.6 mT PEMFs group, OA group and normal control （NO group. Osteoarthritis was induced （OA and PEMFs groups） by injecting 0.2 mg monosodium iodoacetate into the rat＇s right knee joint. The Rats in the PEMFs groups were exposed to 75 Hz, 0.8rot or 1.6 mT PEMFs for 2h/day for 4 weeks. Toluidine blue stain and OARSI score were used to investigate changes of cartilage structure. Micro-computed tomography （micro-CT） was used to analysis sub- chondral bone microarchitecture. Result： Compared with the OA group, cartilage surface was relatively complete and had mild fibrillation, and tide line was clear in both PEMFs groups. No significant difference was found between PEMFs and OA groups in the OARSI score （P〉0.05）. Compared with the OA group, there was a significant increase in the tra-becular thickness and number, and a significant decrease in the trabecular separation in 1.6mT PEMFs group（P〈 0.05）.0.8mT PEMFs group showed a significant decrease in the trabecular thickness and bone volume fraction, and a significant increase in the trabecular number and bone surface/bone volume（P〈0.05）. No significant differ- ence was found in subchondral bone microarchitecture between two PEMFs groups（P〉0.05）. Conclusion： PEMFs might have beneficial effects on the structure of cartilage and subchondral bone in knee OA rats. However, no different effect exists between 1.6mT PEMFs and 0.8roT PEMFs.