Abstract W P262: Neuroprotective Effect of Nattokinase Mediated by Inhibition of Platelet Aggregation and Thrombosis in Photothrombotic Stroke

Background and Purpose: Thrombolysis remains the only effective and approved medical treatment of acute ischemic stroke. Nattokinase is a potent fibrinolytic enzyme purified from the fermented soybean cheese Natto. The fibrinolytic activity and thrombolytic effects of nattokinase have been observed both in vitro and in vivo. Here, we determined whether nattokinase may have a beneficial effect in photothrombotic stroke. Methods: The plasma fibrinolytic activity of nattokinase was measured by euglobulin clot lysis times (ECLT). Arterial thrombus formation was investigated using in vivo ferric chloride induced thrombosis model. To determine the effect of nattokinase in ischemic brain injury, we treated nattokinase at 1h, 2h, and 4h before operation and induced a photothrombotic stroke model in mice. Results: The ECLT was significantly shortened by administration of nattokinase. Nattokinase inhibited the ferric chloride induced arterial thrombosis. Nattokinase improved relative cerebral blood flow in both ischemic region and non-ischemic region. Nattokinase significantly reduced infarction volume at 4h treatment (26.2 ± 6.5 mm3, n=5, p=0.019) compared to that of vehicle control (42.9 ± 2.5 mm3, n=7) in photothrombotic stroke. Conclusions: These findings indicate that nattokinase improved blood flow by inhibiting platelet aggregation and thrombus formation and significantly induced neuroprotective effect in ischemic brain damage. These results suggest that nattokinase may have therapeutic benefits in ischemic brain injury.