Cerebrovascular responses to pathophysiological insult in diabetic rats.

Diabetes mellitus is associated with altered cerebrovascular responsiveness and this could contribute to the pathology of stroke in diabetic patients. In these studies, we used a model of haemorrhagic stroke (intrastriatal injection of 50 microl blood) to examine subacute perilesional perfusion and blood-brain barrier (BBB) integrity in spontaneously diabetic rats. Volumes of striatal oligaemia (blood flow < 35 ml 100 g(-1) min(-1)) were significantly increased (>300%) in diabetic rats with intrastriatal blood, compared to either non-diabetic rats with blood or control diabetic rats with striatal injection of silicon oil. However, the increase in BBB permeability was both qualitatively and quantitatively similar in diabetic and control rats. Poorer outcomes following haemorrhagic stroke in diabetic patients may thus result from dysfunctional cerebrovascular control, and particularly decreased dilatatory reserve.