ANTIHYPERTENSIVE EFFECT OF SESAMIN - III - PROTECTION AGAINST DEVELOPMENT AND MAINTENANCE OF HYPERTENSION IN STROKE-PRONE SPONTANEOUSLY HYPERTENSIVE RATS

The antihypertensive effect of sesamin, a lignan from sesame oil, was examined using salt-loaded and unloaded stroke-prone spontaneously hyp ertensive rats (SHRSP). The animals at 6 weeks of age were separated i nto a salt-loaded group and an unloaded group, Salt-loaded animals wer e maintained on 1% NaCl drinking water. Each group was further divided into two groups: normal-diet group and sesamin-diet group. Systolic b lood pressure of all animals was monitored once weekly At the end of t he feeding periods, cardiovascular hypertrophy and renal damage were e valuated. In the salt-loaded group, sesamin feeding significantly supp ressed the development of hypertension, and efficient suppression was maintained from 9 to 26 weeks (e.g., 215+/-4 vs. 180+/-4 mmHg, at 17 w eeks old). The left ventricle plus septum weight-to-body weight ratio was slightly but significantly lowered by sesamin feeding. When the de gree of vascular hypertrophy of the aorta and superior mesenteric arte ry was histochemically evaluated, wall thickness and wall area of thes e vessels were significantly decreased by the sesamin feeding, Histolo gical renal damage such as thickening of the tunica intima and fibrino id degeneration of the arterial wall were often observed in the normal -diet group, but this damage was efficiently reduced in the sesamin-fe d animals. On the other hand, in the salt-unloaded group, only a sligh t and nonsignificant suppressive effect of sesamin on the development of hypertension was observed, Although the wall area of the aorta was significantly decreased by the sesamin feeding, other vascular paramet ers were not ameliorated, The incidence of histological renal damage t ended to decrease in sesamin-fed animals, but these alterations were n ot statistically significant. Thus, sesamin feeding was much more effe ctive as an antihypertensive regimen in salt-loaded SHRSP than in unlo aded SHRSP, thereby suggesting that sesamin is more useful as a prophy lactic treatment in the malignant status of hypertension and/or hypert ension followed by water and salt retention.