Effect of Dietary Sodium Nitrite Supplementation on Spontaneous Intracerebral Hemorrhage in Stroke-Prone Spontaneously Hypertensive Rats

Diet-derived nitrite can benefit cardiovascular function. However, the effects of nitrite supplementation on idiopathic intracerebral hemorrhage (spontaneous ICH) are unclear. This study, therefore, investigated the impacts of chronic nitrite supplementation on the survival rate and risk for spontaneous ICH in stroke-prone spontaneously hypertensive/Izumo strain (SHRSP/Izm) rats fed with a high-salt diet. Experimental study I-six-week-old male rats were categorized into two groups: (1) SHRSP+salt, in which rats were administered saline drinking water, and (2) SHRSP+salt+nitrite, in which rats were administered nitrite-added saline drinking water for 14 weeks each. The survival curves during this period did not vary significantly between the groups. However, nitrite administration markedly reduced the incidence of ICH and the extent of cerebral hemorrhage. Experimental study II-the impacts of nitrite supplementation on blood pressure in salt-loaded 8-week-old male SHRSP/Izm rats were evaluated for >4 weeks. During the first week, systolic blood pressure was remarkably lower in the nitrite group than in the control (without nitrite feeding). Similarly, at week 4, cardiac mass and brain mass were significantly lower. In conclusion, nitrite treatment reduced the extent of cerebral hemorrhage caused by hypertension and administration of a high-salt diet.