Mechanism of Accumulation and Elimination of Organic Solvent-soluble Fluorescence Substance (Lipofuscin Like Substance) in Rat Myocardium Induced by a Fish Oil Supplement Diet

Abstract

We investigated the mechanism of cardiac lipofuscin accumulation induced by a short-term intake of fish oil supplemented diet. Rats were fed with the ordinary diet (control group) for 8 weeks, the ordinary diet for 4 weeks followed by a 5 % sardine oil-supplemented diet for 4 weeks (fish oil group), or the 5% fish oil-supplemented diet for 4 weeks followed by the ordinary diet for 4 weeks (wash-out group). Ultramicroscopic examination of ventricular myocytes in the fish oil group revealed a marked accumulation of lipofuscin (p<0.01 vs. control group). However, this accumulation was barely detectable in both of the control group and the wash-out group. The organic solvent-soluble fluorescence compounds were analyzed by the reversed-phase HPLC in the myocardial tissue in the fish oil group. The content of those compounds was significantly higher in the fish oil group than those found in the control group and the wash-out group (p<0.01). Myocardial content of vitamin E was significantly reduced in rats fed with the fish oil diet (p<0.01). It can be concluded that the short term intake of fish oil supplemented diet induces cardiac lipofuscinosis through the lipid peroxidation metabolism and the lipofuscin accumulated in the myocardium can be eliminated by the termination of the oil supplemented diet.