An experimental model of myasthenia myopathy

Normal and thymectomised rabbits been have immunized by means of a thymic extract emulsified with Freund's Complete Adjuvant. The experiment was conducted over a three month period, in order to reproduce an experimental model of chronic myasthenia. During this period immunological, electromyographic and histologic studies were undertaken. Typical findings of partial neuromuscular block were invariably obtained from all the non thymectomized animals, while such signs were constantly absent both in non-treated control rabbits and in the immunized thymectomized ones. This neuromuscular block was intermittent. The compromised neuromuscular conduction was associated to an histological pattern of autoimmune myopathy. Evidence was put on antibodies directed against the thymus, muscular and nervous tissue. The results indicate the important role of the thymus gland both in altering conduction at the neuromuscular junction level and causing histopathologic muscle lesions.