Quantitative analysis of labelled inner retinal proteins in experimental optic neuritis

In order to determine if axonal transport changes in chronic experimental allergic encephalomyelitis (EAE) were due to blockade or increased discharge of fast transported proteins from the inner retina, we examined the presence of pulse labeled proteins in autoradiograms of the optic nerve head, retinal ganglion cell and nerve fiber layers of juvenile strain-13 guinea pigs with chronic EAE and normal controls. Quantitative analysis of silver grains, performed six and twenty-four hours following the intravitreal injection of tritiated leucine, showed a decrease in inner retinal radioactivity in those with EAE, whereas no difference was detected between the two groups after three days. Grain counts within the optic nerve heads of guinea pigs with EAE were reduced at all time intervals studied. These results are consistent with an increase in discharge of fast transported proteins from retinal ganglion cells into optic nerve axons and support our previous observations of increased radioactivity at the foci of optic nerve demyelination.