Figure 6.

Vacuolar lesions in the nervous system of rodents. (A) Intramyelinic edema in the dorsal hippocampus of the brain of a rat treated with triethyltin. Large numbers of vacuoles are present within the dorsal hippocampal commissure, the corpus callosum and the cingula. H&E. (Image is courtesy of Dr. Robert H. Garman, Consultants in Veterinary Pathology, Murrysville, PA.) (B) Compound-induced foamy cytoplasmic vacuolation in the spinal cord ventral horn motor neurons of a rat resulting from phospholipidosis (confirmed using electron microscopy). H&E. (Image is courtesy of Dr. Anna-Lena Berg, Safety Assessment, Pathology, AstraZeneca, S-151 85 Södertaälje, Sweden.) (C) Mucocytes (“Buscaino bodies”) in the optic nerve of a dog. These are a common processing artifact associated with extended immersion in ethanol during paraffin infiltration (typically by over-the-weekend holding on an automated processor) and manifest as pale, blue-gray, amorphous bodies in H&E-stained sections. H&E. They are positive for periodic acid-Schiff (PAS), are birefringent under polarized light, and probably represent degraded myelin. (D) Sciatic nerve injury in a Lewis rat. Axons are disrupted as indicated by digestion chambers (arrow), with multifocal myelin fragmentation. H&E. (E) Luxol fast blue stain of sciatic nerve injury in a Lewis rat. When compared to a contralateral control nerve, there is a marked reduction in staining for myelin sheaths. (F) Labeling to demonstrate ED-1 (a rat macrophage marker) of the same sciatic nerve reveals numerous positive macrophages in demyelinated areas. (Images D, E and F are courtesy of Dr. Karima Kahlat, Department of Physiology and Pharmacology, School of Medical Sciences, University of Bristol, United Kingdom.)