Pathological and pathogenetic changes in the central nervous system of guinea pigs given tunicamycin.

Guinea pigs were injected with tunicamycin and the sequential morphological alterations in the brain examined to investigate further the pathogenesis of cerebral lesions in this experimental model of annual ryegrass toxicity, a central nervous system disease of livestock caused by members of the tunicamycin group of antibiotics. Brain damage was most commonly observed in the cerebellum, and the important alterations in the development of degenerative parenchymal lesions appeared to be largely referrable to changes in small blood vessels. Endothelial damage, with increased vascular permeability, resulted in capillary obstruction leading to localised ischaemia and hypoxic neuronal damage. There was evidence for several possible mechanisms which may have contributed to vascular occlusion.