抗原诱导兔关节炎模型的建立及早期磁共振表现

目的建立抗原诱导兔关节炎模型并分析其早期磁共振表现。方法7只新西兰兔采用卵清白蛋白致敏后于右膝关节注射相同抗原进行关节炎动物模型的诱导，观察诱导后第5、15天膝关节磁共振表现并作病理对照。结果6只兔右膝关节炎诱导成功，平扫见关节滑模增生、关节积液增多，T1WI均显示为等或稍低信号，T2WI显示为不均匀高信号，两者不易区分，经Gd—DTPA增强扫描后关节滑膜显示为明显强化而关节积液未见明显强化。与第5天图像比较，关节内注射后15天滑膜增生更明显。组织学观察可见右膝关节滑膜增厚、衬里层细胞的增多，衬里及衬里下层炎性细胞浸润，炎性细胞大多为淋巴细胞、单核细胞和巨噬细胞细胞。结论从发病机理、病理表现及磁共振影像等各方面看，抗原诱导兔关节炎模型都是一种较理想的类风湿关节炎动物模型。

Establishment of a Experimental Antigen-induced Arthritis in Rabbit and Evaluation of its MRT Manifestations

Objective To establish a experimental rabbit model of antigen-induced arthritis and discuss its MRI manifestations.Methods Unilateral arthritis was induced by means of intraartieular injection of ovalbumin in 7 knees of 7 rabbits that had been presensitized to the same antigen.All knees were imaged at 5,15 days after onset of arthritis.MR findings were correlated with histopathologic findings.Results 6 knees with intraarticular injection of antigen suspension developed unilateral arthritis.Precontrast image showed thickening of joint effusion and synovium.The Joint effusion or synovium showed hypo-or/so-intensity on T1-weighted spin-echo,while inhomogeneouos hyper-intensity on T2-weighted spin-echo.It could be difficult to differentiated from one another.Postcontrast image (after Gd-DTPA administration) showed marked enhancement,whereas joint effusion did not.Synovium increasing was more distinctive on 15 day than on 5 day after intraarticular injection.The results of histopathologic evaluation confirmed the MR findings,with presence of marked to extensive synovial hyperplasia in all 6 arthritic knees of the antigen-injected group.Cellular infiltrates containing monocytes,lymphocytes,and macrophages were noted within the hyperplastic synovium of the arthritic knees.Conclusions The pathological process development and MRI manifestations in the rabbit model of antigen-induced arthritis is similar to that in human beings,so that it is a good lab model of rheumatoid arthritis.