Lack of apoE causes alteration of cytokines expression in young mice liver

To investigate the effect of apolipoprotein E (apoE) on cytokine expression profile of the liver of young mice, quantitative RT-PCR (qRT-PCR) assay and cytokine antibody array for multiplex analysis of 62 cytokines have been used to analyze characteristics of expression of cytokines in the liver of 6-week-old apoE-null (apoE(-/-)) mice. The levels of plasma cytokines were also analyzed. The mRNA level of IL-1 beta, IL-2, IL-6, ICAM-1, VCAM-1, MCP-1, NF-kappa B (p65), IFN-gamma and I kappa B-alpha were increased significantly in apoE(-/-) mice comparative to wild-type (WT) mice. IL-4, IL-10 and GM-CSF, however, were slightly decreased. Compared with WT, levels of 21 cytokines altered twofold or more in apoE(-/-) mice, including 10 cytokines increased and 11 decreased. Expression patterns of IL-1 beta, IL-2, IL-4, IL-6, IL-10, GM-CSF, IFN-gamma and VCAM-1 showed identical trend between cytokine antibody array and qRT-PCR analysis. Moreover, levels of IL-1 beta, IFN-gamma and IL-6 in the plasma were elevated, while IL-4 was lightly decreased in apoE(-/-) mice compared to those in WT mice. These results implied that promotion of type I immune response in the liver of young apoE(-/-) mice due to alteration of these cytokines, and the phenotypes may be caused by the regulation of NF-kappa B. The inflammation and lipid metabolism dysfunction in the liver cooperated in dysfunction of the liver in young apoE(-/-) mice.