激素性股骨头缺血坏死MSCT灌注成像与VEGF表达的实验研究

Experimental Investigation of Multi-slice CT Perfusion and Vascular Endothelium Growth Factor Expression in Steroid Induced Femoral Head Necrosis

目的:探讨激素性股骨头缺血坏死(AvNFH)的MSCT灌注成像和VEGF表达特征。方法:20只新西兰大耳白兔,其中实验组共16只,每周两次臀肌注射甲基强的松龙8 mg/kg,在给药后第2、4、6、8周周末各处死4只大白兔;对照组共4只兔,在2、4、6、8周周末各处死1只。所有动物于处死前行双侧股骨头MSCT灌注检查,计算血流量、峰值增强值(PEI)、峰值增强时间(PTT)、平均通过时间(MTT)等指标。动物处死后取双侧股骨头制作病理切片,行HE染色和VEGF免疫组化染色。结果:在给予激素后早期股骨头内血流量开始下降,随着时间的延长下降更明显;仅在给药后4周,股骨头内PEI下降,MTT增加。给予激素后2周,VEGF在软骨细胞内表达最强,其后表达略有下降,但仍明显高于对照组;给药后6周VEGF在成骨细胞内的表达明显增加。MSCT灌注参数与VEGF在成骨细胞、软骨细胞中的阳性表达率无显著相关性(P>0.05)。结论:MSCT灌注成像能够反映股骨头微循环变化,激素性AvNFH时不同类型的细胞VEGF表达情况不同,且与MSCT灌注成像参数之间无明显相关性。

Objective：To investigate the characteristics of multi-slice CT （MSCT） perfusion and the vascular endothelium growth factor （VEGF） expression of steroid induced femoral head necrosis in adult rabbits. Methods：20 adult rabbits （1.0-1.5 years of age） were divided into two groups, 16 rabbits as experiment group which were intramuscularly injected methylprednisolone （8mg/kg） twice a week,4 rabbits were used as control group. For the experiment group, every 4 rabbits were sacrificed at the end of the 2nd,4th,6th,8th week,and at the same time span,one rabbit of the control group was sacrificed. All rabbits had MSCT perfusion before sacrifice. MSCT perfusion parameters of bilateral femoral head including blood flow （BF）,peak enhanced attenuation （PEA）,peak transit time （PTT）, mean transit time （MTT） were calculated. Histopathology section of bilateral femoral head using HE stain and immunohistochemical stain for VEGF were performed. Results：Two weeks after administration of steroid,decrease of BF in femoral head began, then became more obvious as time elapsed. At the 4th week,decrease of PEA and increase of MTT were showed in the femoral head. At the 2nd week,expression of VEGF in chondrocytes reached the peak,then decreased gradually,but still obviously higher than that of the control group. The peak of VEGF expression of osteoblasts was reached at the 6th week. For the parameters of MSCT perfusion and VEGF expression, there was no statistical difference between the 2 types of cells （P〉0.05）. Conclusion：Changing status of the microcirculation of femoral head can be assessed by MSCT perfusion. The VEGF expression in steroid induced avascular necrosis of femoral head varied according to different cell types. There was no statistical correlation between parameters of MSCT perfusion and VEGF expression.