^(99)Tc^m-SZ-63放免显像在激素性骨坏死实验研究中的应用

Preliminary application of radioimmunoscintigraphy with ^(99)Tc^m labeled anti-fibrin monoclonal antibody(SZ-63) in experimental steroid-induced osteonecrosis in rabbits

目的 评价99Tcm 抗人纤维蛋白单克隆抗体 (SZ 6 3)放射免疫显像在激素性骨坏死早期诊断中的应用价值 ,并探讨激素性骨坏死的发病机制。方法 健康成年家兔 19只 ,随机分为 2组。实验组 ,14只用联合马血清和激素法制备激素性骨坏死动物模型。另 5只以生理盐水替代马血清或激素进行相同注射作对照组。耳缘静脉注射99Tcm SZ 6 3185MBq后 4h行家兔股部前后位平面显像。采集结束后 ,从显像图上勾划双侧股骨头和股骨干等面积感兴趣区 (ROI) ,计算股骨头 干放射性摄取比值。显像结束后 ,处死动物 ,取股骨头进行组织病理学检查并与显像结果进行对比研究。结果组织病理学检查 ,实验组 14只家兔中骨标本中发生 1级或 2级骨坏死 10只 (71.43% ) ,未见骨坏死征象 4只 (2 8.5 7% ) ,对照组 5只均未见明显异常。99Tcm SZ 6 3放免显像 ,注射后 4h ,家兔股部血池影清晰 ,有骨坏死组股骨两端呈局限性放射性浓聚区 ,以股骨头部为著 ;而无骨坏死组与对照组均未见明显异常放射性浓聚。骨坏死组、无骨坏死组和对照组股骨头 干放射性摄取比值分别为 2 .16± 0 .35、1.6 8± 0 .2 9和 1.5 7± 0 .12 ,前两者差异有显著性 (P <0 .0 5 ) ,而后两者差异无显著性 (P >0 .0 5 )。

Objective To evaluate the feasibility of radioimmunoscintigraphy of steroid-induced osteonecrosis with 99 Tc m labeled monoclonal antibody against human fibrin(SZ-63)and to explore the mechanisms postulated in the pathogenesis of steroid-induced osteonecrosis. Methods Experimental steroid-induced osteonecrosis was produced by intravenous horse serum combined with intraperitoneal high-dose of dexamethasone in 14 healthy adult rabbits, and then radioimmunoscintigraphy with 99 Tc m-SZ-63 was performed. The acquired images were analyzed in comparison with histopathological findings. The other 5 healthy adult rabbits received injection of normal saline instead of horse serum or steroids were used as control. Results The histopathological observation showed that 10 of 14 model rabbits(71.43%) had osteonecrosis in the femoral head (osteonecrosis group) and no osteonecrosis signs were found in the remaining 4 model rabbits (28.57%, non-osteonecrosis group) and either in the control group. In the osteonecrosis group, the radioactivity uptake increased markedly in both ends of the femur, especially in the femoral head 4 h after injection of 99 Tc m-SZ-63. No abnormal signs were observed in both the non-osteonecrosis group and the control group.The radioactivity ratios of femoral head to trunk were 2.16±0.35, 1.68±0.29 and 1.57±0.12 in osteonecrosis group, non-osteonecrosis group and control group, respectively. There was statistical difference between the former two groups( P <0.05) but no difference between the latter two groups( P >0.05). Conclusions Steroid-induced osteonecrosis is correlative to thrombosis. Radioimmunoscintigraphy with 99 Tc m-SZ-63 could specifically detect in vivo thrombosis of the steroid-induced osteonecrosis in the rabbit models, and it may provide a great potential of early noninvasive diagnosis of osteonecrosis and screening high-risk group of steroid-induced osteonecrosis.