RESUMO
In vivo magnetic resonance imaging (MRI) was used to observe the effect of acutobin, a purified thrombin-like enzyme (TLE), isolated from the snake venom of Deinagkistrodon acutus, on MRI-detected brain lesion volume and tissue perfusion deficit in a hyperglycemic rat right middle cerebral artery occlusion/reperfusion (MCAO/R) model. Acutobin (0.75 U/ml) was intravenously injected with a dosage of 2.5 U/kg body weight 30 min after MCAO (MCAO duration=60 min) and again 24 h after reperfusion. Multislice diffusion weighted imaging (DWI) and single-slice dynamic bolus tracking gradient echo (GE) imaging were sequentially acquired before and after MCAO/R. DWI-detected lesion volume was significantly (p<0.05) reduced by 24-31% from 350+/-45, 369+/-45 and 374+/-36 mm(3) in the saline-treated group to 239+/-17, 282+/-26 and 259+/-32 mm(3) at 3, 4 and 24 h after reperfusion in the acutobin-treated group, respectively. Residual cerebral blood flow (CBF) in the right hemisphere recovered and remained at approximately 80% of normal perfusion over the measurement period in the acutobin-treated group, compared to approximately 40% in the saline-treated group. Mortality at 1 week after MCAO/R in the acutobin-treated group was significantly lower (25% mortality) than the saline control group (85% mortality). Our results indicate that acutobin improves brain tissue perfusion and reduces infarct volume and mortality in the hyperglycemic rat MCAO/R model.
