Paige J A, Liao R, Hajjar R J, Foisy R L, Cory C R, O'Brien P J, Gwathmey J K
Department of Medicine, Harvard Medical School, Boston, MA, USA.
Cardiovasc Res. 1996 Feb;31(2):249-62.
Omega-3 fatty acids have been implicated in the amelioration of cardiovascular disease in humans. Since these fatty acids are found in salmonid fish and are known to be essential for all salmonids, this study was undertaken to determine the effect of a high dietary intake of omega-3 fatty acids on the function of trout myocardium.
Rainbow trout (Oncorhynchus mykiss) from a single stock population were divided into two groups and fed either a diet high in omega-3 fatty acids (i.e. 4.0%) or low in omega-3 fatty acids (i.e. 2.1%) for 3 months. Heart function was studied at the whole heart and isolated muscle level.
In whole heart preparations, peak developed pressures in freely ejecting hearts from salmonids fed the high omega-3 fatty acid diet were significantly greater than the hearts from salmonids fed the low omega-3 fatty acid diet (21 +/- 1.5 vs. 11.5 +/- 0.9 mmHg respectively, P < 0.05). These data correlated with results from isolated muscle preparations of myocardium from fish fed high and low omega-3 fatty acid diets (4.12 +/- 0.32 vs. 3.08 +/- 0.28 mN/mm2 respectively, P < 0.05). The calcium uptake rate of heart homogenates from fish fed the high omega-3 diet was slower and sarcoplasmic reticulum Ca2+ ATPase activity was lower. The myofilament force-calcium relationship in myocardium from trout fed the low omega-3 diet was shifted leftward on the calcium axis to lower intracellular calcium concentrations (delta 0.4 pCa units) compared to mammalian myocardium. This resulted in greater activation at lower intracellular calcium concentrations. However, trouts fed diets high in omega-3 fatty acids had [Ca2+] required for half maximal activation more similar to what has been reported for mammalian myocardium (delta 0.1 pCa unit). Furthermore, the myofilaments of trout hearts appear to show less cooperativity (Hill coefficient approximately 1) than has been found in mammalian myocardium (Hill coefficient > or = 2).
Our experimental results demonstrate for the first time that dietary omega-3 fatty acid content affects myocardial force of contraction by affecting calcium metabolism and myofilament calcium-activation.
ω-3脂肪酸被认为与人类心血管疾病的改善有关。由于这些脂肪酸存在于鲑科鱼类中，并且已知对所有鲑科鱼类都是必需的，因此进行本研究以确定高膳食摄入ω-3脂肪酸对虹鳟心肌功能的影响。
将来自单一养殖群体的虹鳟（Oncorhynchus mykiss）分为两组，分别喂食高ω-3脂肪酸（即4.0%）或低ω-3脂肪酸（即2.1%）的饲料3个月。在整个心脏和分离的肌肉水平上研究心脏功能。
在全心脏制剂中，喂食高ω-3脂肪酸饲料的鲑科鱼类自由射血心脏的最大发展压力峰值显著高于喂食低ω-3脂肪酸饲料的鲑科鱼类的心脏（分别为21±1.5与11.5±0.9 mmHg，P<0.05）。这些数据与喂食高、低ω-3脂肪酸饲料的鱼类心肌分离肌肉制剂的结果相关（分别为4.12±0.32与3.08±0.28 mN/mm2，P<0.05）。喂食高ω-3饲料的鱼类心脏匀浆的钙摄取率较慢，肌浆网Ca2+ATP酶活性较低。与哺乳动物心肌相比，喂食低ω-3饲料的虹鳟心肌中肌丝力-钙关系在钙轴上向左移动，以降低细胞内钙浓度（δ0.4 pCa单位）。这导致在较低细胞内钙浓度下有更大的激活。然而，喂食高ω-3脂肪酸饲料的虹鳟达到最大激活一半所需的[Ca2+]与哺乳动物心肌报道的更相似（δ0.1 pCa单位）。此外，虹鳟心脏的肌丝似乎比哺乳动物心肌表现出更低的协同性（希尔系数约为1）（希尔系数≥2）。
我们的实验结果首次证明，膳食中ω-3脂肪酸含量通过影响钙代谢和肌丝钙激活来影响心肌收缩力。
