A case of spontaneous myocardial necrosis and cerebral ischemic lesions in a laboratory beagle dog

Abstract: A beagle dog treated with saline as a control animal in a preclinical study was euthanized due to sudden systemic deteriora-tion. On histopathological examination, contraction band necrosis of myocardial cells was observed widely in the left ventricular wall, including the papillary muscle and apex, and observed slightly in the ventricular septum and left atrium. In the brain, necrosis was observed in neurons and glia of the cerebral cortex, hippocampal pyramidal cells, glial cells of the rostral commissure and Purkinje cells of the cerebellar vermis. It is highly probable that the marked systemic deterioration was caused by cardiac dysfunction due to the spontaneous contraction band necrosis of the myocardial cells, although the pathogenesis of the myocardial lesions remains unclear. Given the distribution of neuronal necrosis in the brain, it is likely that these lesions resulted from the ischemia responsible for acute cardiac failure. (DOI: 10.1293/tox.2015-0024; J Toxicol Pathol 2015; 28: 233–236) Key words: contraction band necrosis, ischemic brain lesion, spontaneous lesion, beagle dog Unexpected sudden death of laboratory beagles is a very rare event in toxicological research. The present case was euthanized due to sudden systemic deterioration, pos-sibly due to acute cardiac failure. On histopathological ex-amination, contraction band necrosis of myocardial cells in the heart and ischemic changes in the neurons and glia in th