关键词: 疾病模型, 股骨头坏死, 冷冻, 组织病理学, 兔

Abstract: Objective To establish a reliable and therapeutic available rabbit model of osteonecrosis of the femoral head（ONFH）using a novel liquid nitrogen freezing method. Methods Twenty-one New Zealand white rabbits were recruited in this study.Aseptically, gluteus muscles were bluntly separated, the bilateral round ligaments of the femur were cut off and the femoral heads were exposed. Medical cotton stickers were dipped in liquid nitrogen and then used to frozen the bilateral femoral heads by three times alteration of freezing and rewarming. The femoral heads of the model were examined by gross morphology, X-ray photography, and histopathology at 3 days, 7 days, 2 , 4 , 6 and 8 weeks post-operation, respectively. Results X-ray photography showed that the bone density of femoral heads increased at 2 weeks, and was not uniform at 4 weeks post-refrigeration. After 6 weeks, the femoral heads presented irregular shape and a marginal lucent area.Then collapsed joint surface, widened joint space, and blurred epiphyseal plate were observed at 8 weeks post-refrigeration. Gross morphology manifestly demonstrated an aggravating cartilage and bone injury of femoral heads with time elapsed. Histopathologic results showed that necrosis of chondrocytes and osteocytes occurred at 3 days after freezing,and bone trabeculae of femoral heads were collapsed and disarranged at 2 weeks post-refrigeration. Adipocytes necrosis, angiogenesis, and proliferation of fibrous tissue appeared in bone marrow cavity at 4 weeks. Creeping substitution was visible at 6 weeks. Depository growth of new bone was seen and cells dwelled in epiphyseal plate became crushing and deformation at 8 weeks. Conclusion The novel rabbit model of ONFH by liquid nitrogen freezing method presented here has lower trauma,and approximates to pathological changes of human ONFH, and may be used in ONFH therapeutic related studies including stem c

Key words: Disease model, Femur head necrosis, Freezing, Histopathology, Rabbit