[Variation of lipids in rats fed a cholesterol diet (author's transl)]

Experimental hyperlipemia induced by a high cholesterol diet (HCD) in male Sprague-Dawley rats was investigated by measuring lipid levels in serum, liver and aorta. For old rats were fed a laboratory chow diet containing 0.5, 1.0 and 2.0% of cholesterol, for 6 weeks. Serum total lipid (TL) and total cholesterol (TC) in 1.0% HCD were markedly increased and reached peaks by feeding HCD for 18 to 21 days. Although the degree of increase in serum TL and TC was similar in both 0.5 and 2.0% HCD groups, these levels decreased more rapidly in the former and more slowly in the latter, after the levels had been reached a peak. The serum free cholesterol level reached a peak in those fed 0.5% HCD for 12 days and those fed 1.0% HCD for 21 days, but the subsequent reduction was smaller in extent as compared with serum TL and TC. Serum phospholipid (PL) level reached a peak in those fed both 0.5 and 1.0% HCD groups for 12 days and this level was maintained until 42 days in the 1.0% HCD group. Serum triglyceride (TG) levels increased during the first half of the experimental period, but decreased in the second half, with no significant difference between the 0.5 and 1.0% HCD groups. Cholesterol in high density lipoprotein (HCD-C) decreased in rats on the HCD and there was a tendency toward reversion to normal levels from the 4th week in the group on the 2.0% diet, however, a continual decrease occurred in the 0.5 and 1.0% groups. The change in phospholipid in HDL (HDL-PL) was similar to that of HDL-C in both the 0.5 and 1.0% HCD groups. In liver lipids, TL and TC were markedly increased by HCD, but TG increased at first and then decreased as did serum TG. Liver PL decreased by 0.5 and 1.0% HCD groups. In aorta lipids, TL and TC decreased. As a remarkable increase in serum lipids and decrease in HDL-C and HDL-PL were continuous in the 1.0% HCD in comparison with 0.5 or 2.0% HCD, 1.0% HCD appears to be the most suitable experimental model of hyperlipemia in rats. In addition, it is considered that 0.5% HCD is suitable for investigation of the effect of a drug for a relatively short period of treatment.