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目的探讨兔早期激素性股骨头缺血性坏死模型建立方法,应用MRI和病理学检查评价其有效性。方法取6月龄家兔20只,体质量2~3 kg,随机分为实验组和对照组,每组10只。实验组动物于双侧臀肌交替注射地塞米松磷酸钠注射液(10 mg/kg),每3天注射1次,共14次;对照组于双侧臀肌注射等量生理盐水(10 mg/kg)。造模期间观察动物一般情况;6周后行股骨头MRI检查及大体、组织学观察。结果对照组动物未出现明显脱毛、食量及运动改变;实验组动物第6周出现脱毛加重,食量减少,轻微跛行。MRI检查示,对照组双侧股骨头形态规则,股骨头内未见异常信号;实验组双侧股骨头形态欠规则,股骨头内可见斑片状不规则异常信号,软骨下骨坏死、囊变,骨小梁稀疏。冠状面剖开股骨头后大体观察,对照组股骨头软骨面平整、光滑,股骨头剖面呈红色;实验组股骨头软骨表面失去光泽、变薄,可见片状软骨下出血、坏死,股骨头剖面呈浅红色。组织学观察示,对照组股骨头内骨小梁粗大,骨陷窝内骨细胞形态正常;实验组骨小梁变细和稀疏,部分断裂,骨细胞核固缩,空骨陷窝明显增多。对照组和实验组空骨陷窝率分别为8.0%±0.5%和49.0%±0.3%,比较差异有统计学意义(t=21.940,P=0.000)。结论经短期、冲击、大剂量给予地塞米松成功构建兔早期激素性股骨头缺血性坏死模型,可通过MRI及病理学检查对模型进行有效评价。
Objective To investigate the method of early steroid-induced osteonecrosis of the femoral head in rabbits, and evaluate its effectiveness by MRI and pathology. Methods Twenty rabbits of 6 months old were randomly divided into experimental group and control group with 10 rats in each group. Animals in the experimental group were injected dexamethasone sodium phosphate injection (10 mg / kg) alternately in the bilateral gluteal muscles for 14 times every 3 days. The control group was injected with equal amount of normal saline (10 mg / kg). Animals were observed during the modeling of the general situation; 6 weeks after the femoral head MRI examination and gross, histological observation. Results The animals in the control group showed no obvious hair removal, food intake and exercise changes. In the 6th week, the animals in the experimental group showed increased hair loss, decreased appetite and slight limpness. MRI examination showed that there were no abnormal signals in the femoral heads in the control group. The shape of the bilateral femoral heads in the experimental group was irregular, the irregular abnormal signals in the femoral heads, subchondral bone necrosis and cystic degeneration Trabecular thinning. After the femoral head was cut off from the coronal plane, the femoral head was smooth and the femoral head was red in the control group. The surface of the femoral head cartilage was lightened and thinned in the experimental group, showing the lamellar subchondral hemorrhage and necrosis and the femoral head profile Was light red. Histological observation showed that the trabecular bone was thick in the femoral head and normal in the lacunar fossa. In the experimental group, the trabecular bone was thinner and thinner, partially broken, the nuclear pyknosis of the nucleus and the empty lacuna were obviously increased. The empty lacunae in the control group and the experimental group were 8.0% ± 0.5% and 49.0% ± 0.3%, respectively, with significant difference (t = 21.940, P = 0.000). Conclusions The model of early steroid-induced avascular necrosis of the femoral head in rabbits can be constructed successfully by short-term, high-dose and high-dose dexamethasone. The model can be effectively evaluated by MRI and pathological examination.