Comparison of two rat models of cerebral ischemia under hyperglycemic conditions

Hyperglycemia worsens outcome of stroke either in the clinical setting or in animal models. In the present study, two focal cerebral ischemia models, permanent middle cerebral artery occlusion (MCAO, 3-4 h) and reversible MCAO (1 h ischemia + 3 h reperfusion), under hyperglycemic conditions were compared. Using 2,3,5-triphenyltetrazolium chloride staining to define viable tissue, this resulted in the infarction area being confined primarily to the cerebral cortex in the permanent MCAO group, while it extended to the subcortical area in the reversible MCAO group, and the lesion areas were respectively 27.7 +/- 5.3% and 46.8 +/- 12.0% of the ipsilateral hemisphere (P = 0.012). Hyperglycemia accelerated the cerebral damage compared to normoglycemia and ascorbic acid pre-treatment maintained tissue viability during the acute phase of hyperglycemic MCAO. In conclusion, hyperglycemia combined with either of the two MCAO models resulted in rapid infarction associated with increased oxidative stress. The hyperglycemic models are suitable for pharmaceutical therapeutic studies of antioxidant efficacy.