Axonal damage in myelin oligodendrocyte glycoprotein peptide-induced experimental autoimmune encephalomyelitis in a C57BL/6 mouse model may be not secondary to inflammatory demyelination

The present study established a chronic experimental autoimmune encephalomyelitis model in C57BL/6 mice induced by myelin oligodendrocyte glycoprotein peptides and complete Freund's adjuvant. Onset latency was 12 days, with an incidence rate of 100%. Neuropathological characteristics included perivascular inflammatory cell infiltration, demyelination, neuronal degeneration, and axonal damage within cerebral and myelic white matter. Electron microscopy revealed swollen mitochondria, complete organ disappearance, and fused or broken myelin sheath structure, which were accompanied by myelin sheath reconstruction. Moreover, axonal damage was not consistent with demyelination distribution, and severity of axonal damage did not correlate with demyelination. Results suggested that axonal damage in an experimental autoimmune encephalomyelitis model is not secondary to inflammatory demyelination.