Postnatal undernutrition accelerates incidence of stroke in stroke-prone spontaneously hypertensive rats

The effect of infantile nutritional levels on the development of hypertension and incidence of stroke was investigated in stroke-prone spontaneously hypertensive rats (SHRSP). Caloric intake was varied during the suckling period by manipulating litter size immediately after birth; however, all animals had free access to food after weaning. Animals reared in large litters of 15 (LL group) weighed significantly less than those in small litters of 5 (SL group) at every age. In the LL group, systolic blood pressure (mean +/- SD) increased age-dependently to reach 237 +/- 16 mm Hg at 14 weeks of age, and 14 of 15 rats developed stroke from 14 to 19 weeks of age. On the other hand, in the SL group, the blood pressure at 14 weeks of age was 213 +/- 6 mm Hg, which was significantly lower than that in LL group, and stroke occurred only in 3 of 10 rats kept up to 22 weeks. When the drinking water was replaced with a 1% salt solution, the onset of stroke markedly accelerated in both groups; more than 90% of rats developed stroke within 18 days after the salt-loading. However, the time required for the onset of stroke signs was significantly shorter in the LL group (10.5 +/- 1.5 days) than in the SL group (15.4 +/- 1.7 days). Furthermore, the blood pressure increment for the first week after the salt-loading was significantly greater in the LL group (29.5 +/- 9.5 mm Hg) than in the SL group (14.2 +/- 3.0 mm Hg). These findings indicate that infantile undernutrition may accelerate the development of hypertension and incidence of stroke in SHRSP.