Nishimura T, Matsumoto T, Nishino M, Tomita K
Department of Orthopaedic Surgery, School of Medicine, Kanazawa University, Japan.
Clin Orthop Relat Res. 1997 Jan(334):37-42.
Although arterial factors have been regarded as playing an important role in the pathogenesis of osteonecrosis, more attention has been given to venous factors because steroids cause an increase in the intraosseous pressure despite a decrease in blood flow in the femoral head. The authors examined changes in the veins of steroid treated rabbits. Forty rabbits were used: 30 rabbits (the steroid treated group) were injected with methylprednisolone acetate (4 mg/kg) weekly and 10 rabbits (the control group) were treated without steroids. The veins around the femoral head, ear veins, femoral veins, and inferior vena cava were obtained after 8 weeks of treatment, and the specimens were examined by immunohistochemical staining and electron microscopy. In the steroid treated group, proliferation of foam cells was observed in the intima of the vein in 7 of 30 rabbits. Immunohistochemical studies, using monoclonal antibodies for smooth muscle cells and macrophages, showed that the foam cells were derived from smooth muscle cells. Electron microscopy showed damage to the endothelial cells and smooth muscle cells. These results indicated that corticosteroids damaged the venous system. It is suggested that steroid induced disturbance of the draining veins causes stasis and that steroids are an important factor in osteonecrosis of the femoral head.
尽管动脉因素在骨坏死发病机制中被认为起着重要作用，但静脉因素已受到更多关注，因为尽管股骨头血流量减少，但类固醇会导致骨内压升高。作者研究了类固醇治疗的兔子静脉的变化。使用了40只兔子：30只兔子（类固醇治疗组）每周注射醋酸甲基泼尼松龙（4mg/kg），10只兔子（对照组）不使用类固醇治疗。治疗8周后获取股骨头周围静脉、耳静脉、股静脉和下腔静脉，通过免疫组织化学染色和电子显微镜检查标本。在类固醇治疗组中，30只兔子中有7只在静脉内膜观察到泡沫细胞增殖。使用平滑肌细胞和巨噬细胞单克隆抗体的免疫组织化学研究表明，泡沫细胞来源于平滑肌细胞。电子显微镜显示内皮细胞和平滑肌细胞受损。这些结果表明皮质类固醇损害了静脉系统。提示类固醇诱导的引流静脉紊乱导致血液淤滞，类固醇是股骨头骨坏死的一个重要因素。
