Murakami T, Ogawa H, Hayashi M, Yoshizumi H
Department of Food Science and Nutrition, Faculty of Agriculture, Kinki University, Nara, Japan.
J Nutr Sci Vitaminol (Tokyo). 1997 Apr;43(2):211-23. doi: 10.3177/jnsv.43.211.
Stroke-prone spontaneously hypertensive rats (SHRSP) were fed a diet containing docosahexaenoic acid (DHA)-enriched Euglena glacilis (DHA-Euglena) as the protein source from 5 weeks of age. The effects on endothelial functions were investigated by perfusion experimentation using mesenteric vasculature, and compared with the effects of antihypertensive drugs. (1) At 13 weeks of age, SHRSP fed the DHA-Euglena diet showed an average blood pressure of 220 mmHg, which was 20 mmHg lower (p < 0.05) than that in the control group, while SHRSP of the captopril-treated group (angiotensin I converting enzyme inhibitor: 200 mg/L drinking water) and hydralazine-treated group (vasodilator: 60 mg/L drinking water) showed marked hypotensive effects with blood pressures of 150-160 mmHg and 180-190 mmHg, respectively. (2) The constriction response to norepinephrine (NE) was lower (p < 0.01) in the mesenteric vasculature isolated from the DHA-Euglena-treated SHRSP than in that from the control group. (3) When the mesenteric vasculature isolated from 13-week-old SHRSP fed the DHA-Euglena diet was perfused with an acetylcholine solution (10(-6) M) in the presence of NE (8 x 10(-6) M), the relaxation rate was 81%, which was higher (p < 0.01) than that in the control group (61%). Among the antihypertensive-treated groups, the captopril-treated group gave nearly the same relaxation rate as the DHA-Euglena diet group, while the hydralazine-treated group indicated a slightly lower rate (65%). At 18 weeks of age, the endothelium-dependent relaxation of SHRSP in the control group was further reduced (28%), but in both the DHA-Euglena diet group and antihypertensive-treated groups, the relaxation rates were not substantially different from the levels at 13 weeks of age. Reduction of the endothelium function in SHRSP occurs due to aging and blood pressure elevation. However, by improving nutritional conditions by the feeding of a DHA-Euglena diet, the endothelial functions were protected without a fall in blood pressure unlike antihypertensive drugs. It is hence considered that nutritional improvement helps maintain a sound architecture for the vascular wall, thereby leading to the suppression and delay of onset of cerebrovascular diseases, and subsequently to the prolongation of life-span.
从5周龄起，易患中风的自发性高血压大鼠（SHRSP）被喂食一种以富含二十二碳六烯酸（DHA）的纤细裸藻（DHA-裸藻）为蛋白质来源的饮食。通过使用肠系膜血管进行灌注实验研究其对内皮功能的影响，并与抗高血压药物的作用进行比较。（1）13周龄时，喂食DHA-裸藻饮食的SHRSP平均血压为220 mmHg，比对照组低20 mmHg（p<0.05），而卡托普利治疗组（血管紧张素I转换酶抑制剂：200 mg/L饮用水）和肼屈嗪治疗组（血管扩张剂：60 mg/L饮用水）的SHRSP显示出明显的降压作用，血压分别为150 - 160 mmHg和180 - 190 mmHg。（2）从喂食DHA-裸藻的SHRSP分离的肠系膜血管对去甲肾上腺素（NE）的收缩反应低于对照组（p<0.01）。（3）当在NE（8×10⁻⁶ M）存在下，用乙酰胆碱溶液（10⁻⁶ M）灌注从13周龄喂食DHA-裸藻饮食的SHRSP分离的肠系膜血管时，舒张率为81%，高于对照组（61%）（p<0.01）。在抗高血压治疗组中，卡托普利治疗组的舒张率与DHA-裸藻饮食组几乎相同，而肼屈嗪治疗组的舒张率略低（65%）。18周龄时，对照组SHRSP的内皮依赖性舒张进一步降低（28%），但DHA-裸藻饮食组和抗高血压治疗组的舒张率与13周龄时的水平没有实质性差异。SHRSP内皮功能的降低是由于衰老和血压升高所致。然而，通过喂食DHA-裸藻饮食改善营养状况，内皮功能得到了保护，与抗高血压药物不同，血压没有下降。因此，认为营养改善有助于维持血管壁的健全结构，从而导致脑血管疾病的发生受到抑制和延迟，进而延长寿命。
