Effects of dietary fish oil on lipid peroxidation and serum triacylglycerol levels in psychologically stressed mice

Objective The intake of ω-3 polyunsaturated fatty acids and psychological stress can each induce tissue lipid peroxidation. In our present study, we investigated their combined effects on the oxidative status of mouse tissues. Methods Mice were group-housed (four mice/cage) and fed a diet containing fish oil (as a source of ω-3 polyunsaturated fatty acids), soybean oil, or olive oil for 3 wk. These animals were then 1) housed under the same conditions (four per cage, control group) or 2) individually housed to generate psychological stress conditions (isolation stress). After 2 wk of isolation stress, the levels of thiobarbituric acid-reactive substances (an index of lipid peroxidation) and antioxidants in the liver and kidney and the serum levels of triacylglycerol were measured. Results Fish oil–fed mice showed increased levels of thiobarbituric acid-reactive substances in their livers and kidneys compared with soybean oil- or olive oil–fed mice. These increases in thiobarbituric acid-reactive substance levels in the fish oil–fed mice were less profound under isolation stress conditions when compared with the group-housed animals on the same diet. In the fish oil–fed mice, isolation stress led to an increase in liver vitamin E levels when compared with their group-housed counterparts. The fish oil–fed mice exhibited lower serum triacylglycerol levels compared with the soybean oil- or olive oil–fed mice, and this decrease was more profound under conditions of isolation stress when compared with group-housing conditions. Conclusion Dietary fish oil combined with isolation stress results in lower levels of lipid peroxidation in the liver and kidney compared with dietary fish oil alone.