Occurrences of ON and axonal loss in MHV-infected and EAE mice. (a) ON, determined by presence of any level of inflammation in the optic nerve, is detected as early as day 3 post inoculation with MHV-A59. Incidence increases by day 5, persists at day 7, and resolves by day 15. In contrast, almost no MHV-2-infected mice develop ON over the same time course. Mean ± SEM incidence from 3 experiments is shown. (b) The peak incidence of MHV-A59-induced ON, detected at day 5 postinoculation, was 48% (10 of 21 nerves) whereas only one of 21 nerves from MHV-2-infected mice developed ON. 60% (6 of 10) of optic nerves from EAE (experimental autoimmune encephalitis; autoimmune model for demyelination) mice develop ON at the peak of inflammation on day 11 post immunization. (c) The area of axonal staining (mean ± SEM) detected by Bielschowsky silver impregnation is significantly lower in optic nerves from MHV-A59-infected mice as compared to optic nerves from control, uninfected mice or MHV-2-infected mice (*). (adapted from the work of [94]).
