Myelin and PSLs modulates the macrophages phenotype by PPARβ/δ activation. (a-c) Relative NO and IL-6 concentration in supernatants of LPS stimulated control, myelin- or PSL-treated macrophages. Prior to administration of myelin or PSLs, cells were treated with antagonists for PPARα (GW6471), PPARβ/δ (GSK0660) or PPARγ (GW9662). The relative NO and IL-6 production is defined as the production of NO in experimental cultures divided by values in stimulated control cultures. Data represent the mean ± SEM of five independent experiments. (−): control cultures in which no antagonists were added.