Fish oil increases atherosclerosis and hepatic steatosis, although decreases serum cholesterol in Wistar rat

BACKGROUND: It is known that fish oil consumption decreases incidence of cardiovascular disease. However, some studies showed that it increases atherosclerosis as it does not get completely metabolized by the liver. The aim of the present study was to investigate the effects of fish oil on aortic atherosclerosis, hepatic steatosis and serum lipids in rats. METHODS: Twenty pregnant Wistar rats were fed with a fish oil-containing diet or standard diet (containing soy bean oil) during pregnancy and lactation and the pups were weaned onto the same diet. Fasting blood samples, hepatic and aortic specimens were taken from pups on day 70 postnatal. Data were analyzed with SPSS software, using t-test, Mann-Whitney test and Spearman correlation coefficient. Values of p < 0.05 were considered significant. RESULTS: Medians for fatty streak in aorta of fish oil fed and soy bean oil fed pups were 1.00 and 0.00, respectively, and P value was 0.042. Also, medians for ductular cell hyperplasia of liver in fish oil fed and soy bean oil fed pups were 1.00 and 0.00, respectively, and P value was 0.014. Total cholesterol in pups fed with fish oil was 52.20 mg/dl and in pups fed with soy bean oil was 83.90 mg/dl (p < 0.00) and for low density lipoprotein cholesterol (LDL-C) values were 8.79 mg/dl and 13.16 mg/dl, respectively (p = 0.031). CONCLUSIONS: According to the results of the present study, a diet which provided 15.9% of energy from fish oil as the only source of dietary fat, induced aortic atherosclerosis as well as hepatic steatosis in Wistar rat, although it decreased total cholesterol and LDL-C.