被动转移法致自身免疫性重症肌无力兔模型的建立

Passive Transfer of Experimental Autoimmune Myasthenia Gravis in Rabbits with IgG of Myasthenia gravis patients

目的用重症肌无力患者的免疫球蛋白（IgG）建立兔急性被动转移性实验性自身免疫性重症肌无力动物模型。方法提取重症肌无力患者血中的IgG，并将其腹膜内注入长耳白兔，观察实验兔的临床症状、AChR—Ab滴度、神经肌肉接头电传导功能和病理形态学的变化。结果实验兔于被动转移后第2天渐出现肌无力症状，第3～5天肌无力加重。实验组血清AChR—Ab吸光度较空白对照组和健康对照组显著性增高（P〈0．01）。重复神经电刺激实验（repetitive nerve stimulation，RNS）动作电位衰减率和单纤维肌电图检查平均连续波间值差异均较空白对照组和健康对照组显著延长（P〈0．01）。实验组微小终板电位的波幅和频率较空白对照组和健康对照组均显著性降低（P〈0．01）。实验组单位面积的神经肌肉接头数较空白对照组和健康对照组显著性减少（P〈0．05）。结论被动转移重症肌无力患者的IgG可以诱导出重症肌无力家兔模型。

Objective To create experimental autoimmune myasthenia gravis （EAMG） rabbits by passive transfer the IgG. Methods Crude immunoglobulin fractions of myasthenia gravis patients were prepared by ammonium sulphate precipitation at 33% saturation and purified by chromatography on DEAE-Sephadex A-50. Experimental animals were injected IgG intraperitoneally （ i. p） and the phenotype was graded in 4 levels. Anti-acetylcholine receptor antibodies were evaluated using enzyme linked immunosorbent assay （ELISA） and electrophysiological function was assessed by repetitive nerve stimulation （RNS） , single fibre electromyograpby （SFEMG） and miniature endplate potential （MEPP） tests. Histological studies were evaluated using immunohistology. Results The second day after the passive transfer, all the rabbits in experimental group showed clinical signs of fatigability and weakness and the weakness exacerbated on the third day. Clinical symptoms could be attenuated by neostigmine. Anti-acetylcholine receptor antibodies were significantly higher in experimental group than in the healthy control and control groups （P 〈 0. 01 ）. At 3,5,10 Hz, the decrement of compound muscle action potential （CMAP） and the mean of consecutive difference （MCD） of all the rabbits were significantly higher in experimental group than in the healthy control and control groups （P 〈0.01 ）. The amplitude and frequency of MEPP in experimental group decreased significantly comparing with healthy control group and control group （ P 〈 0. 01 ）. The quantity of neuromuscular junction per unit area （25 mm^2 ） in experimental group decreased significantly comparing with the healthy control group and control group （P 〈 0. 05 ）. Conclusions The rabbit model of EAMG can be created by passive transfer the IgG of myasthenia gravis patients to rabbits.