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

OBJECTIVE: The intake of omega-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 omega-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.