Consumption of bonito extract suppresses the decrease in cerebral blood flow in stroke-prone spontaneously hypertensive rats.

The effect of consuming bonito extract (BE) on cerebral blood flow was evaluated in stroke-prone spontaneously hypertensive rats (SHRSP), a cerebrovascular disease model. BE dissolved in drinking water was given to 5-week-old male SHRSP for 7 weeks. Tap water was given to the control group. At the age of 12 weeks, blood flow and vascular diameter were measured in the middle cerebral artery. Both cerebral blood flow and cerebral vessel width were greater in the BE group than in the control group. Also, stroke occurred in 7 (with death in 2) of the 8 animals in the control group but in none of the 6 animals in the BE group. To clarify its mechanism, the expressions of nitrogen oxide synthase (NOS) and the superoxide dismutase activity (SOD) in the brain were evaluated. NOS mRNA expression and SOD activity in the cerebrum were higher in the BE group. These results suggest that the consumption of BE suppresses the decrease of cerebral blood flow and reduces the risk of stroke to maintain vasorelaxation through the production of nitrogen oxide and suppression of active oxygen generation.