Study on animal model of experimental autoimmune myasthenia gravis in rats

[Objective] To study the animal model of experimental autoimmune myasthenia gravis (EAMG) induced with extract from electric organ of Narcine timilei in rats. [Methods] Lewis rats were immunized with the protein extracted from electric organ of Narcine timilei, the clinical manifestations were observed every day, and repetitive nerve stimulation (RNS),single fiber electromyography (SFEMG) and the levels of acetylcholine receptor antibody (AChRAb) were detected on the 49th days post immunization. [Results] The content of the protein extracted from electric organ of Narcine timile was 35.4 mg/mL, and the protein could respond with AChRAb from the serum of seropositive myasthenia gravis (MG) patient. The mild symptoms were observed on 3 experimental rats after a week, which lasted for 2 to 5 days. And after 5 weeks, all experimental rats presented some symptoms at different degree like MG. The positive rate of RNS of the experimental group was 75%, and the attenuation rate of these rats was higher than that of control rats. The mean consecutive difference (MCD) of experimental rats were longer than that of control rats markedly (P 0.01). The levels of AChRAb of experimental rats were higher than that of CFA control rats significantly (P 0.01), and the values of P/N of 7 experimental rats were more than 2.1, those of the control rats were less than 1.4. [Conclusion] These pointed out that the extract from electric organ of Narcine timilei could serve as the antigen to induce EAMG for further research on MG.