AimTo investigate the effects of acute hyperglycemia on cerebral ischemia/reperfusion injury (CIRI) and analyze the relationship between blood glucose levels and the extent of CIRI as well as the prognosis.MethodsRats were subjected to 90 min middle cerebral artery occlusion (MCAO).To induce acute hyperglycemia, rats received 25% glucose or 0.9% sodium chloride (10 mL/kg body weight) via the intraperitoneal route 30 min before MCAO.At 24 h after reperfusion, the serum creatine kinase brain isoenzyme (CK-BB) levels, infarct volumes, brain tissue water contents, symptoms of neurological impairment, brain pathological changes and the degree of neuronal apoptosis were assessed.ResultsHyperglycemic group displayed lower survival rate and more severe brain pathological changes than the control group (p<0.05), infarct volumes, apoptosis, brain tissue water contents, the risk of intracranial hemorrhage (p<0.05), neurological deficits and the level of serum CK-BB (p<0.01) were all significantly higher than those in the control group.The levels of serum CK-BB and blood glucose concentrations displayed linear relationship before ischemia-reperfusion.ConclusionsAcute hyperglycemia aggravates cerebral ischemia-reperfusion injury possibly by increasing edema, promoting apoptosis and elevating the level of serum CK-BB.Thus, high blood glucose levels are associated with more severe brain damage and poorer prognosis.