造模早期兔激素性股骨头坏死骨质结构动态变化影像学观察

Dynamic observation of the bone structure in steroid-induced osteonecrosis of femoral head in early rabbits modeling

目的动态观察兔激素性股骨头坏死造模2周之内局部骨质结构影像学与组织学变化,分析股骨头骺上区、骺下区及小转子的变化有无一致性。方法45只普通级新西兰大耳兔随机分为对照组(n=15)与实验组(n=30),实验组建立激素性股骨头坏死模型。造模后第5、7、9、11、13 d分批行CT、MRI、Micro-CT与组织学检查,分析检查结果及其在骺上区、骺下区与小转子等不同部位的差异性。结果实验组常规CT及MRI检查股骨头形态、密度/信号等未见异常改变;Micro-CT见骺上区随造模时间延长逐步出现骨小梁变细、稀疏、部分断裂和骨小梁间距增宽,第9 d时变化有统计学意义(P<0.05),而骺下区及小转子的改变不明显。组织学检查见实验组随造模时间延长,骺上区脂肪细胞增大,骨小梁变稀疏,部分断裂,空骨陷窝增多,髓腔内可伴发出血;骺下区及小转子骨小梁清晰整齐,未见空骨陷窝及髓腔内出血。结论早期兔激素性股骨头坏死局部骨质结构呈现逐步加重的疏松变化趋势,主要发生部位为骺上区。

Objective To dynamically observe the changes of local bone structure and histology within 2 weeks in the rabbit model of steroid-induced femoral head necrosis and analyze whether the changes are consistent in the superior epiphyseal region,the subepiphyseal region and the lesser trochanter.Methods 45 New Zealand big-eared rabbits were randomly divided into a blank control group(15)and an experimental group(30).After modeling,CT,MRI,micro-CT and histological examination were performed in batches 5,7,9,11 and 13,and the differences of the examination results in the superior epiphyseal region,the subepiphyseal region and the lesser trochanter were analyzed.Results There were no abnormal changes in femoral head on morphology,conventional CT and MRI.Micro-ct showed that trabecular thinning,sparsity,partial fracture and trabecular spacing in the superior epiphyseal region gradually appeared with the extension of modeling time,and the changes on day 9 were statistically significant(P<0.05),while the changes in the subepiphyseal region and lesser trochanter were not significant.Histological examination showed that with the prolongation of modeling time,fat cells in the superior epiphyseal region increased,bone trabeculae became sparse and partially fractured,empty bone lacunae increased,and blood could be produced in the medullary cavity.The bone trabeculae of the subepiphyseal region and the lesser trochanter were clear and neat,and no lacunae and intramedullary hemorrhage were observed.Conclusion The bone structure of early steroid-induced osteonecrosis of the femoral head in rabbits showed a trend of gradual aggravation,which mainly occurred in the superior epiphyseal area.