Some similarities in vascular effects of oleic acid and oxidized low-density lipoproteins on rabbit aorta
Review articleOpen access
Xi-Lin Niu - No affiliation found
1995/01/01 Full-length article DOI: 10.1016/S0022-2828(08)80048-X
Journal: Journal of Molecular and Cellular Cardiology
X.-L. Niu, L.-Y. Liu, M.-L. Hu and X. Chen. Some Similarities in Vascular Effects of Oleic Acid and Oxidized Low-Density Lipoproteins on Rabbit Aorta. Journal of Molecular Cell Cardiology (1995) 27, 531–539. In the present study oxidized low-density lipoproteins (ox-LDL) was prepared by a new simple method: oxidizing LDL by electrolysis-generated fee radicals. In endothelium-intact norepinephrine(NE)-precontracted rabbit aortic rings, ox-LDL (2 mg protein/ml)-incubation for 30 min or 3 mM oleic acid for 10 min. significantly attenuated the acetylcholine (ACh)-induced endothelium-dependent relaxation (EDR) (both P<0.01 v control). Such attenuated EDR were sustained alter washout. The oleic acid-induced endothelial dysfunction was associated with concomitant reduction of cGMP level in aortic rings. Preincubation of aortic rings with 500 μm L-arginine or 100 u/ml superoxide dismutase for 10 min partly prevented the oleic acid-induced attenuation of EDR and reduction of cGMP, indicating that oleic acid may impair the L-arginine-nitric acid pathway and/or inactivate the nitric oxide. Both ox-LDL and oleic acid potentiated NE-induced aortic ring contraction (both P<0.01 v. control). Such potentiating effects were abolished by preincubation with 1 μM verapamil, indicating the possible involvement of calcium influx in vascular smooth muscle cells during the enhanced contraction. Gas-chromatographic analysis showed that oleic acid content is the highest among all free fatty acids in ox-LDL. In conclusion, we found that oleic acid possesses certain similar vascular effects as ox-LDL in inducing endothelial dysfunction and in enhancing NE-induced vasocontraction in rabbit aortic ring. We proposed that the vasoactive effects of ox-LDL may be resulted partly from the activation or release of active oleic acid molecule during oxidative moditication of LDL.
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