Moore J N, Cook J A, Henry M M, Jonsson H T, Spicer K M, Wise W C, Halushka P V
Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens 30602.
Eicosanoids. 1991;4(1):47-55.
Endotoxin stimulates macrophages to synthesize membrane-associated inflammatory mediators including eicosanoids and procoagulant activity (PCA). Alpha linolenic acid, a component of linseed oil, is metabolized to eicosapentaenoic acid, which may replace arachidonic acid in membrane phospholipids. Thus, ingestion of linseed oil may alter the generation of eicosanoids, PCA and other membrane-dependent responses. This study compared the in vitro endotoxin-induced synthesis of eicosanoids and expression of PCA by peritoneal macrophages obtained from rats fed a control diet and rats fed a diet enriched with linseed oil. The effect of endotoxin on in vivo plasma eicosanoid concentrations, leukogram, and microvascular permeability were determined. Endotoxin (5 ug/ml) stimulated synthesis of iTxB2, i6-keto PGF1 alpha and expression of PCA by macrophages in vitro. These in vitro responses of macrophages from linseed oil fed rats were significantly less than those of macrophages from control rats. In contrast, there were no significant differences in in vivo responses to endotoxin. The fatty acid composition of total lipids and phospholipids in liver and plasma from linseed oil fed rats and control rats were not different. These composite data suggest several possibilities: (1) linseed oil may have effects independent of alpha-linolenic acid on macrophage function, (2) linseed oil may alter the fatty acid composition of macrophage phospholipids prior to changing that of other tissues, and (3) the reduced in vitro responses of peritoneal macrophages may not reflect the systemic responses to endotoxin.
内毒素刺激巨噬细胞合成包括类花生酸和促凝血活性（PCA）在内的膜相关炎症介质。亚麻酸是亚麻籽油的一种成分，可代谢为二十碳五烯酸，后者可能取代膜磷脂中的花生四烯酸。因此，摄入亚麻籽油可能会改变类花生酸、PCA及其他膜依赖性反应的产生。本研究比较了从喂食对照饮食的大鼠和喂食富含亚麻籽油饮食的大鼠获得的腹膜巨噬细胞，在体外对内毒素诱导的类花生酸合成及PCA表达的情况。还测定了内毒素对体内血浆类花生酸浓度、白细胞计数和微血管通透性的影响。内毒素（5微克/毫升）在体外刺激巨噬细胞合成iTxB2、i6-酮基PGF1α并诱导PCA表达。来自喂食亚麻籽油大鼠的巨噬细胞的这些体外反应明显低于来自对照大鼠的巨噬细胞。相比之下，体内对内毒素的反应没有显著差异。喂食亚麻籽油大鼠和对照大鼠肝脏及血浆中总脂质和磷脂的脂肪酸组成没有差异。这些综合数据提示了几种可能性：（1）亚麻籽油可能对巨噬细胞功能具有独立于α-亚麻酸的作用；（2）亚麻籽油可能在改变其他组织的脂肪酸组成之前先改变巨噬细胞磷脂的脂肪酸组成；（3）腹膜巨噬细胞体外反应的降低可能无法反映对内毒素的全身反应。
