Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory demyelinating disease of the central nervous system mainly associated with autoantibodies against the glial water channel protein aquaporin-4 (AQP4). A number of NMOSD related animal models have recently been reported. For example, general NMOSD models are produced by peripheral injection of immunoglobulin from NMOSD patients (NMO-IgG) in experimental autoimmune encephalomyelitis mice or intra-cerebral administration of NMO-IgG with human complement in naïve mice. In addition, AQP4-specific adoptive transfer model was also reported. But AQP4 immune process is not involved in these NMOSD models. On the other hand, creation of an AQP4-immunized mice model with clinical and histologic manifestations of CNS autoimmunity has proven challenging.
In the present study, we tried to create AQP4 peptide-induced experimental autoimmune encephalomyelitice mice as NMOSD model.
Female C57BL/6J mice were used. Mice were subcutaneously immunized with 200 μg of AQP4 p201-220 peptide emulsified in complete Freund’s adjuvant supplemented with Mycobacterium tuberculosis extract H37Ra (Day 0). Pertussis toxin (400 ng) was administered at Days 0 and 2. Mice were sequentially scored for clinical symptoms according to the following scale: 0, no disease; 1, limp tail; 2, hind limb weakness; 3, hind limb paresis; 4, hind limb paralysis; 5, hind limb and fore limb paralysis; 6, moribundity and death.
Total ten mice were immunized, four of which showed clinical symptoms within Day 34; two mice were clinical score 2, the other mice were clinical score 3.
NMOSD like model can be created by AQP4-immunization. Now, we are conducting additional experiments to examine the detailed characterization of this model, for example histopathological profiling such as AQP4 and astrocyte pathology in the spinal cord.