Orally administered conjugated linoleic acid ameliorates allergic dermatitis induced by repeated applications of oxazolone in mice.

Conjugated linoleic acid (CLA) is one of the constituents of animal products with possible health benefits such as anti-carcinogenic and anti-obesity effects. In this study, we investigated the immunomodulatory effects of CLA using a mouse model of allergic dermatitis. Mice were orally administered either a CLA mixture containing equal amounts of 9c, 11 t-CLA and 10 t, 12c-CLA, or high linoleic acid safflower oil, and allergic dermatitis was induced on the ear by repeated topical applications of oxazolone. Oral administration of the CLA mixture but not the high linoleic safflower oil attenuated the symptoms of allergic dermatitis in both ear weights and clinical scores. This effect was associated with decreased levels of ear interleukin-4 (IL-4) and plasma immunoglobulin E. The immunomodulatory effects of the CLA isomers were compared by an in vitro cytokine production assay. The results showed that 9c, 11 t-CLA, the most predominant isomer in animal products, significantly inhibited IL-4 and interferon-γ production from mouse splenocytes with similar potency to 10 t, 12c-CLA. These findings suggest that CLA, a constituent of animal products, has a potentially beneficial effect for amelioration of allergic dermatitis.

Efficacy of oral administration of heat-killed probiotics from Mongolian dairy products against influenza infection in mice: alleviation of influenza infection by its immunomodulatory activity through intestinal immunity.

Some probiotics possess immunomodulatory activities and have been used as complementary and alternative medicines. We previously found that 10 lactic acid bacteria (LAB) strains isolated from traditional Mongolian dairy products showed probiotic potential in vitro. In this study, we assessed the immunomodulatory activity of 10 LABs on influenza virus (IFV) infection in relation to their efficacies in IFV-infected mice. In an intranasal IFV infection model in mice, oral administration of boiled Lactobacillus plantarum 06CC2 strain (20mg/mouse), one of the 10 LABs, twice daily for 10 days starting two days before infection was significantly effective in protecting the body weight loss of infected mice, reducing virus yields in the lungs on days 2, 4, and 6 after infection, and prolonging survival times without toxicity. The total numbers of infiltrated cells in the bronchoalveolar lavage fluid (BALF), especially macrophages and neutrophils, were significantly reduced by 06CC2 administration on day 2. On day 2, tumor necrosis factor (TNF)-α production in BALF was also reduced significantly, but interferon-α, interleukin-12, and interferon-γ productions were augmented and natural killer (NK) cell activity was significantly elevated. Furthermore, the gene expressions of interleukin-12 receptor and interferon-γ in Peyer's patches were augmented by 06CC2 administration on day 2. Thus, 06CC2 was suggested to alleviate influenza symptoms in mice in correlation with the augmentation of NK cell activity associated with the enhancement of interferon-α and Th1 cytokine productions through intestinal immunity and the reduction of TNF-α in the early stage of infection.

Effects of dietary supplementation with conjugated linoleic acid on fatty acid composition and lipid oxidation in chicken breast meat.

We investigated the effects of dietary conjugated linoleic acid (CLA) on fatty acid composition and lipid oxidation in breast meat of broiler chickens. Broiler chickens (28-day-old females) were fed diets containing experimental oils at 20 g/kg diet for 28 days. The experimental oils consisted of either a 2:0, 1:1, or a 0:2 (wt : wt) ratio of safflower oil (high linoleic acid content) to a commercial CLA mixture. In this study, dietary CLA supplementation significantly increased the composition and content of CLA in chicken meat. The predominant CLA in meat from birds with supplemented diets was the cis-9, trans-11 isomer. The proportion of saturated fatty acid in meat significantly increased with increasing CLA supplementation, with a corresponding decrease in monounsaturated fatty acid. Dietary CLA also reduced thiobarbituric acid reactive substances (TBARS) values in raw meat during storage at 4 degrees C for 5 days. These results provide evidence that CLA feeding is a practical strategy not only for adding nutritional benefits to chicken meat but also for improving meat quality including oxidative stability.

Dietary conjugated linoleic acid reduces cerebral prostaglandin E(2) in mice.

Conjugated linoleic acids (CLA) are naturally occurring fatty acids that have been recognized to modify prostaglandin (PG) production in specific tissues. So far, no relationship between PG production and CLA has been reported in the brain. Thus, the effects of CLA on cerebral prostaglandin E(2) (PGE(2)) levels and cyclooxygenase (COX)-1 and COX-2 mRNA expression in mice were determined in the present study. Mice given the diet with or without 3% CLA at the age of 9 weeks were mated, reproduced and lactated. Offspring mice given each diet until 25 days and 8 weeks of age were sacrificed and their brains removed. Production of PGE(2) was reduced while COX mRNA was quantitatively increased by CLA supplementation. These results imply that brain PGE(2) production can be reduced by dietary CLA without inhibition of COX gene expression in mice.