Hypercholesterolaemia, increase in lipid peroxidation and hyperhomocysteinaemia may contribute to the pathogenesis of
atherosclerosis. This study was performed to examine the effects of repeatedly heated
palm oil mixed with 2%
cholesterol diet on
atherosclerosis in oestrogen-deficient postmenopausal rats.
Ovariectomy causes disruption of tunica intima layer of the rat aorta simulating a postmenopausal condition in females. Twenty-four ovariectomized female Sprague-Dawley rats were divided into four groups. The control group received 2%
cholesterol diet without
palm oil. A diet with 2%
cholesterol content fortified with fresh, once-heated and five-times-heated
palm oil was given to the other treatment groups. The rats were sacrificed at the end of 4 months of study and the aortic arch tissue was processed for histomorphometry and electron microscopy. On observation, there was disruption of the intimal layer of the ovariectomized rat aorta. There was no obvious ultrastructural change in the aorta of the rats fed with fresh
palm oil. The ultrastructural changes were minimal with once-heated
palm oil, in which there was a focal disruption of the endothelial layer. The focal disruption was more pronounced with five-times-heated
palm oil. The results of this study show that the ingestion of fresh
palm oil may have a protective effect on the aorta but such a protective action may be lost when the
palm oil is repeatedly heated. The study may be clinically important for all postmenopausal women who are susceptible to
atherosclerosis.