Altered fatty acid profile in the liver and serum of stroke-prone spontaneously hypertensive rats: reduced proportion of cis-vaccenic acid.

Stroke-prone spontaneously hypertensive rats (SHRSP) are utilized as models for study of the pathogenesis of not only stroke and cardiovascular disorders but also atherosclerosis and metabolic syndrome. Basic information on the profiles of fatty acids and lipid classes in the liver is indispensable to use SHRSP as a model of disorder of lipid metabolism; nevertheless, detailed information on the metabolism of triacylglycerols (TAGs) and fatty acids in the liver of SHRSP is lacking. This study aimed to characterize profiles of lipid classes and fatty acids and to explore the mechanism underlying the characteristic alterations in metabolism of TAGs and fatty acids in the liver of SHRSP, in comparison with spontaneously hypertensive rats (SHR). The characteristic changes observed in SHRSP were (1) markedly lower hepatic TAG contents; (2) altered expressions of genes encoding three enzymes responsible for the control of TAG level, namely, adipose triglyceride lipase (for TAG degradation; up-regulated), carnitine palmitoyltransferase 1a (for fatty acid β-oxidation; up-regulated) and long-chain acyl-CoA synthetase 3 (for glycerolipid synthesis; down-regulated); (3) evidently lower contents and proportions of monounsaturated fatty acids, in particular cis-vaccenic acid (18:1n-7), in the liver and serum; and (4) down-regulation of palmitoleoyl-CoA chain elongase, which is necessary for the biosynthesis of 18:1n-7, in the liver. From the above observations, we concluded that there are significant differences in profiles of lipid classes and fatty acids between SHRSP and SHR, and that altered characteristics in SHRSP are likely responsible for increases in TAG hydrolysis and β-oxidation, and decreases in TAG synthesis and 18:1n-7 synthesis.