Acute tissue response to cerebral ischemia in the gerbil. An ultrastructural study.

The Mongolian gerbil, because of the uniqueness of the anatomical features of its circle of Willis, has become an increasingly useful model in the study of cerebrovascular disease. The present work defines acute changes at the ultrastructural level following ischemic insult. The pathomorphological responses include initial astrocytic involvement and, when the degree of insult is increased, a progression of morphological changes is evident in neuronal and other parenchymal elements. Animals with vessels occluded for more than 3 hr without neurological signs suggestive of ischemia exhibited limited perivascular edema. Contralateral changes (perivascular astrocytic) were observed in the basal ganglia at 24 hr in animals with neurological deficit. Astrocytic and basal ganglia susceptibility to ischemia was consistent with previous findings in primate models. An additional association was found in that limited edematous involvement could exist in animals without neurological deficit but neuronal changes were only present in animals with signs of ischemic neurological deficit.