Effects of cis-9,trans-11 and trans-10,cis-12 conjugated linoleic acid, linoleic acid, phytanic acid and the combination of various fatty acids on proliferation and cytokine expression of bovine peripheral blood mononuclear cells

Abstract

Fatty acids may have an impact on immune functions, which is important in times of increased mobilization of body fat, e.g., around parturition. The aim of the present study was to investigate the effects of the CLA isomers cis-9,trans-11 and trans-10,cis-12, phytanic acid (PA), linoleic acid (LA) and a fatty acid (FA) mixture (containing 29.8% palmitic acid, 6.7% palmitoleic acid, 17.4% stearic acid and 46.1% oleic acid) on the proliferation of bovine blood mononuclear cells (PBMC) in vitro using alamar blue (AB) and 5-bromo-2'-deoxyuridine (BrdU) assay. Quantitative real time polymerase chain reaction analyses were performed to evaluate the expression of interleukin (IL)-4, IL-10, interferon (IFN)-γ, tumor necrosis factor (TNF)-α and peroxisome proliferator-activated receptor (PPAR)-γ in response to cis-9,trans-11 and LA. The IC50 values did not differ between the investigated FA, but there were differences within the proliferation in the response of these FA in a concentration range between 20 and 148 µM (e.g., increased proliferation after treatment with lower concentrations of LA). No differences occurred when different FA combinations were tested. ConA stimulation increased the expression of TNF-α and IFN-γ, whereas IL-10 decreased. In general, neither the baseline expression nor the ConA-stimulated mRNA expression of cytokines and PPAR-γ were affected by the FA. In conclusion, all FA inhibit the proliferation of PBMC dose dependently without significantly altering the induced cytokine spectrum of activated bovine PBMC.

Figure 1

Effects of a fatty acid mixture* (), linoleic acid (), cis-9,trans-11 (), trans-10,cis-12 () and phytanic acid (□) on concanavalin A stimulated proliferation of bovine peripheral blood mononuclear cells (n = 3) in the alamar blue assay (means ± standard deviation). * containing 29.8% palmitic acid, 6.7% palmitoleic acid, 17.4% stearic acid and 46.1% oleic acid according to Rukkwamsuk et al. [22]. a–d: different letters indicate significant differences within the same fatty acid, *, #, $ indicate significant differences between fatty acids at the same concentration, p < 0.05, Tukey test.

Figure 2

Effects of a fatty acid mixture* (), linoleic acid (), cis-9,trans-11 (), trans-10,cis-12 () and phytanic acid (□) on concanavalin A stimulated proliferation of bovine peripheral blood mononuclear cells (n = 3) in the BrdU assay (means ± standard deviation). * containing 29.8% palmitic acid, 6.7% palmitoleic acid, 17.4% stearic acid and 46.1% oleic acid according to Rukkwamsuk et al. [22]. a–c: different letters indicate significant differences within the same fatty acid, *, #, $ indicate significant differences between fatty acids at the same concentration, p < 0.05, Tukey test

Figure 3

Effects of the combination of the fatty acid mixture* (60%) with either 40% linoleic acid (), cis-9,trans-11 () or trans-10,cis-12 () or all 3 of them (each 13.3%, ) on concanavalin A stimulated proliferation of bovine peripheral blood mononuclear cells (PBMC) (n = 3) in the alamar blue assay (means ± standard deviation). * containing 29.8% palmitic acid, 6.7% palmitoleic acid, 17.4% stearic acid and 46.1% oleic acid according to Rukkwamsuk et al. [22]. Med-Con = PBMC incubated without fatty acids and DMSO. a–c: different letters indicate significant differences within the same fatty acid, p < 0.05, Tukey test.

Figure 4

Effects of the combination of the fatty acid mixture* (60%) with either phytanic acid (40%, □) or phytanic acid (20%) and cis-9,trans-11 (20%, ) or phytanic acid (20%) and trans-10,cis-12 (20%, ) on concanavalin A stimulated proliferation of bovine peripheral blood mononuclear cells (PBMC) (n = 3) in the alamar blue assay (means ± standard deviation). * containing 29.8% palmitic acid, 6.7% palmitoleic acid, 17.4% stearic acid and 46.1% oleic acid according to Rukkwamsuk et al. [22]. Med-Con = PBMC incubated without fatty acids and DMSO. a–c: different letters indicate significant differences within the same fatty acid, p < 0.05, Tukey test.