Age-dependent increase in infarct volume following photochemically inducedcerebral infarction: Putative role of astroglia

This study demonstrates that the photochemically induced model of stroke is an extremely viable method of inducing cerebral infarction in old animals. The lesions are reproducible both in terms of location and size and compat ible with long-term survival of the animal. With this model we demonstrated , one week following surgery, a significantly larger infarct in rats 20 and 24 months of age compared to 4-month-old rats. The older rats also sustain ed greater neurologic deficits as assessed on a rotarod task. Older rats al so were characterized by a glial response that was far less intense than in young animals. While the precise relationship between glia activation and cerebral damage remains to be determined, it would appear that a better und erstanding of those factors that contribute to the astrocytic response in t he aged rat mag be of particular benefit in designing therapeutic strategie s aimed at reducing the pathologic consequences of cerebral infarction in e lderly humans.