Malis C D, Leaf A, Varadarajan G S, Newell J B, Weber P C, Force T, Bonventre J V
Massachusetts General Hospital, Department of Medicine, Boston 02114.
Circulation. 1991 Sep;84(3):1393-401. doi: 10.1161/01.cir.84.3.1393.
Vasomotor reactivity may contribute to the pathophysiology of ischemic injury. The atherosclerotic vessel may be particularly susceptible to vasoconstriction because of the damaged endothelial layer with resultant loss of vasodilatory factors. While dietary omega 3 fatty acids have been proposed to protect against vascular occlusion, it is not clear to what extent this results from alterations in the function of platelets or from changes intrinsic to the blood vessel itself.
The effects of dietary supplementation with fish oils on vascular contractility were examined in endothelialized and de-endothelialized aortic rings under pre- and postanoxic conditions. De-endothelialization was defined functionally by the loss of acetylcholine-induced vasodilation in norepinephrine-preconstricted aortic rings from rats fed normal rat chow. Three groups of rats were fed diets containing either 20% menhaden oil or 20% beef tallow, both supplemented with 3% corn oil or 23% corn oil for longer than 4 weeks. All animals received vitamin E. Under well-oxygenated conditions, de-endothelialized aortic rings from rats fed fish oil and corn oil contracted to similar extents with norepinephrine and vasopressin and less than rings from rats fed beef tallow. Endothelialized (intact) and de-endothelialized rings from rats fed fish oil relaxed more in response to acetylcholine than rings from rats fed beef tallow and corn oil. After anoxic exposure and reoxygenation, KCl-induced contraction of intact rings from rats fed fish oil and corn oil was similar and less than rings from rats fed beef tallow. Intact and de-endothelialized rings from rats fed fish oil relaxed more to acetylcholine than did rings from rats fed beef tallow and corn oil.
Under preanoxic or postanoxic conditions, rings from rats fed fish oil and corn oil contracted less than rings from rats fed beef tallow. The relaxation response to acetylcholine, however, was greater in rings from rats fed fish oil than from rats fed either corn oil or beef tallow. These vascular effects of fish oil feeding may result in increased blood flow to ischemic and reperfused tissues in vivo.
血管运动反应性可能参与缺血性损伤的病理生理过程。由于内皮细胞层受损导致血管舒张因子丧失，动脉粥样硬化血管可能对血管收缩特别敏感。虽然有人提出膳食中的ω-3脂肪酸可预防血管阻塞，但尚不清楚这在多大程度上是由于血小板功能改变还是血管本身内在变化所致。
在缺氧前后条件下，对内皮化和去内皮化的主动脉环进行研究，以检测鱼油膳食补充对血管收缩性的影响。通过喂食普通大鼠饲料的大鼠去甲肾上腺素预收缩主动脉环中乙酰胆碱诱导的血管舒张丧失来功能性定义去内皮化。三组大鼠分别喂食含20%鲱鱼油或20%牛脂的饲料，两者均添加3%玉米油或23%玉米油，持续4周以上。所有动物均补充维生素E。在充分氧合条件下，喂食鱼油和玉米油的大鼠的去内皮化主动脉环对去甲肾上腺素和血管加压素的收缩程度与喂食牛脂的大鼠的主动脉环相似且小于后者。喂食鱼油的大鼠的内皮化（完整）和去内皮化环对乙酰胆碱的舒张反应比喂食牛脂和玉米油的大鼠的环更大。缺氧暴露和再氧合后，喂食鱼油和玉米油的大鼠的完整环对氯化钾诱导的收缩相似且小于喂食牛脂大鼠的环。喂食鱼油的大鼠的完整和去内皮化环对乙酰胆碱的舒张反应比喂食牛脂和玉米油的大鼠的环更大。
在缺氧前或缺氧后条件下，喂食鱼油和玉米油的大鼠的环收缩程度小于喂食牛脂的大鼠的环。然而，喂食鱼油的大鼠的环对乙酰胆碱的舒张反应比喂食玉米油或牛脂的大鼠的环更大。喂食鱼油对血管的这些影响可能导致体内缺血和再灌注组织的血流量增加。
