Dietary perilla oil inhibits proinflammatory cytokine production in the bronchoalveolar lavage fluid of ovalbumin-challenged mice

To evaluate the anti-inflammatory effects of different dietary oils on ovalbumin-sensitized and -challenged mice. Experimental BALB/c mice were fed with different diets containing 5% corn oil [rich in linoleic acid, 18:2n-6 polyunsaturated fatty acids (PUFA), as a control diet], 5% perilla oil (rich in alpha-linolenic acid, 18:3n-3 PUFA) or 5% compound oil containing 50% corn oil and 50% perilla oil, for 5 consecutive weeks. The leukocyte count, inflammatory mediators, and cytokine levels, including proinflammatory and Th1/Th2 cytokines in the bronchoalveolar lavage fluid (BALF) from the mice were determined. The results showed that 5% compound oil administration significantly (P < 0.05) decreased eosinophilic infiltration. Dietary perilla oil could not significantly (P > 0.05) decrease the eosinophil accumulation or the secretions of inflammatory mediators such as prostaglandin E-2 (PGE(2)), histamine, nitric oxide and eotaxin. However, dietary perilla oil significantly (P < 0.05) reduced proinflammatory cytokine (TNF-alpha, IL-1 beta and IL-6) and Th1 cytokine (IFN-gamma and IL-2) production. The production of Th2 cytokine IL-10, but not IL-4 and IL-5, was also significantly inhibited by perilla oil administration. The results suggest that dietary perilla oil might alleviate inflammation via decreasing the secretion of pro-inflammatory cytokines in BALF, but failed to regulate the Th1/Th2 balance toward Th1 pole during the Th2-skewed allergic airway inflammation.