Nattokinase Attenuated Excitatory Amino Acids and Cytokines Release and Restored Cerebral Blood Flow in a Thrombolytic Focal Cerebral Ischemic Rat Model.

Objective: Nattokinase (NK), a protease enzyme present in traditional fermented Japanese food, has shown fibrinolytic properties in vitro as well as in cardiac ischemia. In the present study, the Neuroprotective effect of standardized NK was evaluated in the thrombolytic focal cerebral ischemic model.

Methodology: The parameters of behavioural assessment, cerebral blood flow, inflammatory mediators, excitatory amino acids, and immunohistochemistry were measured to support the NK effect. NK was administered at 150 and 300 mg/kg, and its effects were compared with streptokinase (STK) (100μl/rat). Each mg of NK contains 5.5 Units of the enzyme, which can cause lysis of the fibrin.

Results: The results indicate that 7 days of treatment of 300 mg NK restored the cerebral blood flow and prevented the release of cytokine and excitatory amino acids. Similarly, neurological scores were reduced, and grip strength increased significantly with NK treatment. The GFAP and synaptophysin staining of the hippocampus (CA1) and cerebrum have shown recovery of neurons from ischemic damage in comparison to vehicle-treated ischemic-reperfused rats. The NK (300 mg/kg) fibrinolytic effect is comparable to STK treatment.

Conclusion: To conclude, NK, a serine protease, protects the brain from ischemic degeneration in thrombolytic cerebral ischemia. Consumption of this Japanese food might exhibit prophylactic activity.