Induction Of Myasthenia Gravis By Anti-Musk Polyclonal Antibodies In Rats

Objective:To explore the pathogenicity of muscle-specific kinase (MuSK) antibody (MuSKAb) in myasthenia gravis (MG) by inducing the MuSKAb in rats to establish an experimental autoimmune MG (EAMG) model with the similar MG symptoms in human.Methods:According to the method of experiment, we divided12Lewis rats into two groups:experimental group and control group. Then we injected anti-MuSK polyclonal antibodies into experimental group and injected normal saline into control group. After injected, we observed the two groups every3hours and recorded the clinical symptoms until48hours. Furthermore, we executed all the rats and got muscle tissues from the two groups, including intercostals muscle, tibial anterior muscle and gastrocnemius. The frozen sections of muscles were used for immunofluorescence staining and Transmission electron microscope (TEM) to detect experimental index.Results:There was no obvious clinical symptom change in both two groups. No myodynamia decline or decreased activity were observed in the two groups of rats. After immunofluorescence examination, we found that the yellow-green fluorescence appeared around the cell membrane in muscle tissue of experimental group, but did not in control group. The result showed that anti-MuSK polyclonal antibodies bound to the antigen MuSK at cell membranes. In addition, we observed morphological defects (synaptic gutter flattening and a decreased number of slhlike junctional folds) in the neuromuscular junction (NMJ) of experimental group.Conclusion:There is no significant difference in clinical symptos between experimental group and control group after injected48hours. But immunofluorescence and TEM show the positive changes in experimental group. Therefore, further more experiments should be done to explore the role of MuSKAb in pathogenesis of MG...