Inflammatory processes may play a pivotal role in the pathogenesis of cerebrovascular injury in
salt-loaded
stroke-prone spontaneously hypertensive rats (SHRSP). Recent reports revealed that
acetylsalicylic acid (
aspirin) has anti-oxidative properties and elicits
nitric oxide release by a direct activation of the endothelial
NO synthase. The present study was designed to determine whether low-dose
aspirin might prevent cerebrovascular injury in
salt-loaded SHRSP by protecting oxidative damage. Nine-week-old SHRSP were fed a 0.4% NaCl or a 4% NaCl diet with or without treatment by
naproxen (20 mg/kg/day),
salicylic acid (5 mg/kg/day), or
aspirin (5 mg/kg/day) for 5 weeks. Blood pressure, blood brain barrier impairment, mortality, and the parameters of cerebrovascular
inflammation and damage were compared among them. High
salt intake in SHRSP significantly increased blood brain barrier impairment and early mortality, which were suppressed by treatment with
aspirin independent of changes in blood pressure.
Salt loading significantly increased
superoxide production in basilar arteries of SHRSP, which were significantly suppressed by treatment with
aspirin.
Salt loading also significantly decreased NOS activity in the basilar arteries of SHRSP, which were significantly improved by treatment with
aspirin. At 5 weeks after
salt loading, macrophage accumulation and
matrix metalloproteinase-9 activity at the
stroke-negative area in cerebral cortex of SHRSP were significantly reduced by treatment with
aspirin. These results suggest that low-dose
aspirin may exert protective effects against cerebrovascular
inflammation and damage by
salt loading through down-regulation of
superoxide production and induction of
nitric oxide synthesis.