FAT INFILTRATION IN LIVER OF RATS INDUCED BY DIFFERENT DIETARY PLANT OILS - HIGH OLEIC-ACID-OILS, MEDIUM OLEIC-ACID-OILS AND HIGH PETROSELINIC-ACID-OILS

Beneficial effects on health parameters by ingestion of plant oils hav ing high levels of monounsaturated fatty acids such as oleic (cis-9-oc tadecenoic) acid have been described in several studies. Recently, we have shown that feeding of coriander oil containing high proportions o f a positional isomer of oleic acid, i.e. petroselinic (cis-6-octadece noic) acid, led to significantly decreasing proportions of arachidonic (all cis-5,8,11,14-eicosatetraenoic) acid in the cellular lipids. Her e, we report histopathological findings in male Wistar rats fed isocal oric diets containing 2 % corn oil and 12 % (w/w), each, of different plant oils (high-oleic and conventional sunflower oil, olive oil, rape seed oil as well as coriander oil) containing varying levels of monoun saturated fatty acids, i.e. oleic or petroselinic acids. One group of animals was fed a standard diet containing 4 % (w/w) Of fat as control . Liver, heart, aorta, stomach, and spleen were anatomically and histo logically examined. Livers of animals from all the groups that had rec eived high-fat diets except the coriander oil group showed moderate no n-degenerative fat infiltrations of the hepatocytes beginning in the p eriportal fields. Marked to severe fat infiltration was observed in he patocytes of animals fed coriander oil. In this experimental group the livers were found to contain fatty cysts in addition to hepatocytes w ith mixed-size lipid vesicles. Moreover, enlarged nuclei were observed in numerous hepatocytes without fat infiltration. Fat infiltration wa s not observed in livers of animals fed a rat standard diet. In the ce lls of all other organs and tissues studied, in particular heart and a orta, neither non-degenerative fat infiltrations nor other degenerativ e changes were observed for any group. Our results show that feeding o f fat-rich diets containing varying proportions of C-18 cis-monoenoic fatty acids induced different histopathological alterations in the liv ers of rats, depending on position of the double bond. Plant oils cont aining varying proportions of oleic acid lead exclusively to moderate fat infiltration in the hepatocytes, whereas in the animals fed high-p etroselinic coriander oil degenerative alterations (fatty cysts) as we ll as - in several cases - enlarged nuclei were found that are likely due to a non-specific stimulation of the hepatocytes resulting from th e cell degeneration observed.