Heterogeneous immunoreactivity of axonal spheroids in focal symmetrical encephalomalacia produced by Clostridium perfringens type D epsilon toxin in sheep

Abstract

Since axonal injury (AI) is an important component of many veterinary neurologic disorders, we assessed the relative ability of a panel of antibodies (amyloid precursor protein, 3 subunits of neurofilament protein, protein gene product 9.5, ubiquitin, and synaptophysin) to detect axonal swellings or spheroids. Abundant axonal spheroids found in necrotic internal capsule foci produced in 4 sheep by chronic Clostridium perfringens type D epsilon neurotoxicity provided a model system in which to evaluate this important diagnostic tool. There was heterogeneous labeling of subsets of spheroids by the respective antibodies, suggesting that, in order to detect the complete spectrum of AI in diagnostic cases, a range of antibodies should be used, not only when spheroids are plentiful but also when they are few in number or incompletely developed. The application of insufficient markers in the latter cases can potentially lead to the contribution of AI to lesion pathogenesis being underappreciated.

Pathology and Pathogenesis of Brain Lesions Produced by Clostridium perfringens Type D Epsilon Toxin

“…In ETX-exposed sheep following a more protracted clinical course, bilaterally symmetrical foci of necrosis are sometimes found in certain brain regions of predilection, including the basal ganglia, thalamus, internal capsule, midbrain, medulla oblongata, and cerebellar peduncles ( Figure 5 ), this neuropathologic entity being termed FSE [ 20 , 76 , 77 , 78 ]. While these focal, sometimes hemorrhagic, softenings (malacia) have a similar morphologic expression to those found in a few other ruminant neurologic diseases, the different neuroanatomic patterns of lesion distribution in the respective conditions can be diagnostically very useful [ 5 , 79 ].…”