Prophylactic effects of diets on the development of cerebrovascular lesions in stroke- prone spontaneously hypertensive rats (SHRSP)--effects of a fish-protein diet and alterations of lipoprotein metabolism

It is generally accepted that a high-protein diet prevents the development of cerebrovascular lesions and improves the survival rate in studies using stroke-prone spontaneously hypertensive rats (SHRSP). Moreover, it is well documented that the preventive effect is largely due to attenuation of the development of severe hypertension. However, in addition to the reduction of blood pressure, there must be some other mechanisms which are nutritionally effective. In order to elucidate nutritionally effective mechanisms, we investigated the prophylactic effect of a protein diet (the K diet) on the development of cerebrovascular lesions in SHRSP. The diet was composed of dried bonito protein as the protein source and contained the same amount of protein as the control diet (the Funabashi SP diet). Experimental groups were maintained on the K diet from 5 (ca. 130 mmHg), 8 (ca. 200 mmHg) or 10 (ca. 230 mmHg) weeks of age and the control group was maintained on the Funabashi SP diet, with free access to the diet and to drinking water. In the experimental groups administered the K diet from 5 or 8 weeks of age, the development of hypertension was attenuated, there was a reduction of the incidence of cerebrovascular lesions and elongation of the life-span was observed. On the other hand, in the experimental group administered the K diet from 10 weeks of age, a reduction of the incidence of cerebrovascular lesions and an elongation of the life-span were observed without the reduction of blood pressure. Taking the above results into account, we investigated the serum lipid metabolism, which might be affected by the administration of the K diet.(ABSTRACT TRUNCATED AT 250 WORDS)