Relative contribution of individual oxidized components in ox-LDL to inhibition on endothelium-dependent relaxation in rat aorta

W. T. Wong, C. H. Ng, S. Y. Tsang, Y. Huang, Z. Y. Chen

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

Background and Aim: Oxidized low-density lipoprotein (ox-LDL) causes atherosclerosis and endothelial dysfunction. No study up to the present date has examined the relative contribution of all the oxidized components in ox-LDL to inhibition on vascular function. Our aim was to investigate the effects of individual oxidized components at concentrations similar to those in ox-LDL on the impairment of endothelium-dependent relaxation in rat aorta. Methods and Results: Rat thoracic aorta was pre-treated with lysophosphatidylcholine (LPC), cholesterol oxidized products (COPs), oxidized linoleic acid (ox-18:2) and oxidized linolenic acid (ox-18:3) at concentrations similar to those in human ox-LDL. Ox-LDL as a whole caused 61% inhibition while LPC, COPs and ox-18:2 at concentrations similar to those in ox-LDL caused 12%, 24% and 19% inhibition, respectively, on endothelium-dependent relaxation, suggesting that COPs produced the most adverse effect followed by ox-18:2 and LPC in an additional way. Three COPs including 7-ketocholesterol, 7α-hydroxycholesterol and 7β-hydroxycholesterol showed inhibition on endothelium-dependent relaxation with Emax being reduced to 79-87% compared with the control Emax (95%). At Western blot analysis phosphorylation of eNOS at Ser1177 site and total eNOS were not altered by ox-LDL treatment, indicating that ox-LDL did not affect nitric oxide (NO) synthesis capacity. Ox-LDL might react directly with NO and lower NO bioavailability. Conclusion: The present study demonstrated the relative contribution of individual oxidized components in ox-LDL in the inhibition of endothelium-dependent relaxation in rat aorta. This inhibitory effect could be caused by the reduction of NO bioactivity.

Original languageEnglish (US)
Pages (from-to)157-164
Number of pages8
JournalNutrition, Metabolism and Cardiovascular Diseases
Volume21
Issue number3
DOIs
StatePublished - Mar 2011

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Endocrinology, Diabetes and Metabolism
  • Nutrition and Dietetics
  • Cardiology and Cardiovascular Medicine

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