Atherosclerosis 162 (2002) 335 – 344 Sunflower, virgin-olive and fish oils differentially affect the progression of aortic lesions in rabbits with experimental atherosclerosis C.M. Aguilera a, *, M.C. Ramı ´rez-Tortosa a , M.D. Mesa a , C.L. Ramı ´rez-Tortosa b , A. Gil a a Department of Biochemistry and Molecular Biology, Institute of Nutrition and Food Technology, Uniersity of Granada, C/ Ramo ´n y Cajal, 4, 18071 Granada, Spain b Jae ´n City Hospital, Jae ´n, Spain Received 31 March 2001; received in revised form 28 September 2001; accepted 8 October 2001 Abstract In this study we report the effects of sunflower, virgin olive and fish oils on the progression of aortic lesions. A total of 24 male New Zealand rabbits (six per each group) were fed for 50 days on a diet containing 3% lard and 1.3% cholesterol, to induce atherosclerosis. An atherogenic control group (A) was killed after this period and three groups were fed for an additional period of 30 days with a diet composed of (1.75 g of supplemented oil and 98.25 of standard chow): sunflower oil (S), virgin olive oil (O) and fish oil (F). A control group (n =6) was fed with a standard chow diet for 80 days. LDL lipid composition and histological analysis of aortic atherosclerotic lesions were assayed. The atherogenic diet caused a significant increase of cholesterol levels in LDL and aorta tissue. Cholesterol ester content rose significantly in the aortic arch of groups S, O and F. Fatty streaks were found in all aortic sections, although only group S showed a significant progression of the lesion compared with group A. We conclude that the replacement of a high cholesterol-saturated fat diet by another cholesterol free-unsaturated fat diet does not regress atherosclerosis in rabbit. However, sunflower oil provokes a significant progression in lesion development, whereas diet enrichment with extra virgin olive oil and, to a lesser extent, fish oil, stops this progression. © 2002 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Olive oil; Sunflower oil; Fish oil; Atherosclerosis; Rabbits; Aorta; Lipids www.elsevier.com/locate/atherosclerosis 1. Introduction Cardiovascular diseases remain a major cause of mortality worldwide, regardless of the recent advances in medical treatment [1]. Dietary fat is one of the most important environmental factors associated with the incidence of those diseases; diets high in cholesterol and saturated fat have been shown to promote atherosclero- sis [2]. Conversely, dietary polyunsaturated fats have been shown to reduce its development in several species [3,4]. Studies dealing with the effects of monounsatu- rated fatty acids (MUFA) on vascular lesion develop- ment are scarce [5]. This is surprising since traditional Mediterranean diets are followed in geographical areas that have a low incidence of coronary heart disease and they combine a relatively low cholesterol level and the use of olive oil as the main source of fat [6,7]. Support for this approach comes from several randomized con- trolled trials demonstrating that diet modification can reduce coronary events [8] and improve coronary anatomy relative to a Western diet [9]. How diets should be modified apart from reducing saturated fat and cholesterol intake is controversial; the effect of those diets on serum lipoprotein levels is well docu- mented [1] but there have been no trials comparing the effects of diets rich in polyunsaturated fat (n-3 or n-6) and monounsaturated fat on the development of atherosclerotic lesions. * Corresponding author. Tel.: +34-958-248-322; fax: +34-958- 248-326. E-mail address: caguiler@ugr.es (C.M. Aguilera). 0021-9150/02/$ - see front matter © 2002 Elsevier Science Ireland Ltd. All rights reserved. PII:S0021-9150(01)00737-7