间断应用激素法制备兔股骨头缺血性坏死模型

Establishment of a Rabbit Model of Avascular Necrosis of the Femoral Head by Discontinuous Corticosteroid Administration

目的通过比较持续应用激素组与间断应用激素组实验动物在死亡率、X线片、ECT、MRI和光镜下表现,制备激素性股骨头缺血性坏死模型,探讨降低实验动物死亡率的方法。方法40只新西兰大耳白兔分2组。对照组20只,臀肌注射醋酸氢化泼尼松龙,按8 mg/kg,每周两次,共8周16次;实验组20只,臀肌注射醋酸氢化泼尼松龙,按8 mg/kg,注射3周,停药3周,再继续用药5周。分别于注射药物后2、46、、8周处死,取材前分别做X线片、ECT、MRI检查,取材后光镜观察骨髓、骨细胞、骨小梁的变化。结果死亡率比较,实验组明显低于对照组(P<0.05)。X线片、ECT、MRI检查中,两组无明显差异。实验组空缺骨陷窝率为29.5%,对照组为28.9%,经统计学处理无显著性差异(P>0.05)。讨论①大剂量激素对实验动物的打击是相当严重的,对于机体免疫系统和循环系统的损害是其死亡的主要原因。②持续应用激素组与间断应用激素组均制造出成功的股骨头坏死模型,间隔停药期骨组织坏死程度不仅没减轻而是进一步加重。

Objective The aim of this study was to create an improved method to establish a persistent rabbit model of avascular necrosis of the femoral head with reduced death rate. Methods Forty New Zealand rabbits were divided into two groups. The control group consisted of twenty animals receiving hydroprednisone acetate intramuscularly in a dose of 8 mg/kg twice a week for consecutive eight weeks and penicillin injection at the same time. The experimental group consisted of twenty animals receiving hydroprednisone acetate intramuscularly at the same dose twice a week for three weeks and continued to receive it for five weeks after three weeks intermission. All animals were killed and studied by pathology, radiography, ECT and MRI after 2, 4, 6 and 8 weeks. Results The death rate of the animals in the experimental group was much lower than that in the control group （ P 〈 0.01）. There was no significant difference between the two groups in terms of the radiogram, ECT and MRI. All animals were in accordance with the changes of avascular necrosis of the femoral head in the early and middle stage. Histological observation showed no significant difference in the rate of empty bone lacunae between experimental group （29.5 % ） and control group （28.9%）. Conclusions A rabbit model of avascular necrosis of the femoral head has been successfully established by an improved method, i.e. discontinuous administration of corticosteroid, with a significantly reduced death rate of the animals in comparison with that in the model induced by continuous administration of the steroids.