Short-term and long-term pathological effects of glyceryl trierucate and of increasing levels of dietary rapeseed oil in rats.

Abstract

Diets containing rapeseed oil (RSO) or glyceryl trierucate (GTE), each supplying 25 cal% erucic acid, were compared for their effect on the cardiac morphology in male Wistar rats after 1 week, and on growth, pathology and heart and kidney weights after 24 weeks. Sunflowerseed oil (SSO) and a rapeseed oil supplying ca. 4 cal% erucic acid (LER) served as control fats. The RSO and GTE diets produced similar effects. After 1 week, cardiac lipidosis was observed in both dietary groups; after 24 weeks, lipidosis had decreased remarkably and cellular scars were the main pathological feature. The severity of the lipidosis and of the fibrotic changes was similar in both groups. Growth and the relative weights of the heart and kidneys were significantly different – mutually as well as in comparison with the control rats fed SSO. It was concluded that erucic acid is the main pathogenic fatty acid in RSO, but other long-chain fatty acids may also play a minor role. The animals fed LER showed normal growth and organ weights compared with the SSO group. Slight cardiac lipidosis was observed after 1 week. After 24 weeks, some animals showed cardiac cellular scars varying in intensity from slight to moderate. In a second experiment, Sprague-Dawley rats were fed 0, 5, 10, 15, 20, 25 or 30 cal% RSO in diets made isocaloric in fat by addition of SSO. The rats were killed after 3 and 6 days and 32 weeks. All rats fed RSO for 3 and 6 days showed a dose-related lipidosis of the heart. The groups fed RSO for 32 weeks showed myocardial changes which were already manifest in a few animals on the 5 cal% RSO diet. Incidence and severity of these changes increased according as the RSO content of the diet was increased.