Low protein fish vs low protein animal diet enhances the propensity for stroke in stroke-prone/SHR.

Abstract

Weanling male and female, stroke-prone, spontaneously hypertensive rats (SHR/SP) were fed regular commercial rat chow, low protein fish diet, low protein fish diet + 1% saline, low protein animal diet and low protein animal diet + 1% saline. The blood pressure of all of the SHR/SP rose rapidly reaching 240 mm Hg at 90 days of age; blood pressure of low protein fish diet + 1% saline-fed SHR/SP rose most rapidly, reaching levels ranging from 258-300 mm Hg. All of these animals developed acute strokes by 90 days of age; none of the other diet-fed SHR/SP manifested cerebral damage. The protein poor diets prevented normal growth, caused hypogonadism and severely reduced pituitary and adrenal gland weights. The low protein diets were stressful causing significantly increased secretion of ACTH and marked increases in triglyceride, free fatty acid, cholesterol, glucose and BUN [blood urea nitrogen] levels. The mixed hemorrhage-thrombogenic cerebral lesions occurred ipsilaterally in the parietal lobe, involved basal ganglia and appeared in areas of brain tissue nourished by the middle cerebral artery. The inclusion of 1% saline drinking water with a low protein diet of fish tissue origin specifically was synergistic in enhancing the propensity of SHR/SP rats to develop their genetically programmed hypertension and stroke.