Effects of n–3 Polyunsaturated Fatty Acids and Vitamin E on Colonic Mucosal Leukotriene Generation, Lipid Peroxidation, and Microcirculation in Rats with Experimental Colitis

Abstract

Aims: We investigated the effect of n–3 polyunsaturated fatty acids (PUFAs) on mucosal levels of leukotrienes (LTs) and lipid peroxide (LPO), and on mucosal microcirculation, in rats with experimental colitis induced by dextran sulfate sodium (DSS). Methods: We fed Wistar rats a perilla oil-enriched diet containing α-linolenic acid (63.2% of total fatty acids) with various doses of vitamin E for 4 weeks, with 4% DSS added to the drinking water during the last week. Control rats were fed a diet produced from soybean oil containing α-linolenic acid (5.1% of total fatty acids). Colonic mucosal blood flow was measured with a laser Doppler flowmeter. Results: The mucosal level of arachidonic acid was significantly lower and that of eicosapentaenoic acid was significantly higher in the experimental group. The mucosal level of LPO in the experimental group fed a trace or ordinary dose of vitamin E was significantly higher than that of the controls. The production of LTB₄ and LTC₄ from the colonic mucosa in the experimental group was significantly lower than that in controls. However, only the experimental group fed a vitamin E dose 4-fold higher than that given to the controls showed a significant increase in mucosal blood flow. Conclusion: These results suggest that n–3 PUFAs increase mucosal blood flow by inhibiting LT production when there is sufficient vitamin E to inhibit lipid peroxidation in rats with experimental colitis.