[Immunomodulatory role of dietary lipids in an immunosuppressed mouse model and infected with listeria monocytogenes].

INTRODUCTION

Dietary fatty acids immunomodulatory capacity in immunosuppression conditions may differ according to the type of fatty acid present in the diet.

OBJECTIVE

To analyze the effect of different types of dietary lipids on the immune resistance of immunosuppressed and immunocompetent animals, against experimental infection with a virulent strain of Listeria monocytogenes.

METHODS

Balb/c mice were divided into four experimental groups, according to their immunosuppressive treatment: control (PBS), cyclophosphamide (CPA), GK 1.5 and RB6-8C5. Each group was subdivided into four groups according to the lipid diet used which: control, with corn oil 5% (BG); olive oil 20% (AO); fish oil 20% (AP) and sunflower oil 20% (AG). The animals were fed for a month before treatment and subsequently infected with L. monocytogenes.

RESULTS

We show increases in the number of viable bacteria in spleen and liver, and low survival rates in all groups of immunosuppressed mice and also in the PBS group and fed with AP. Furthermore, increases in the lymphocyte proliferation were observed, in the spleen of mice fed with AO and treated with CPA.

DISCUSSION: The AP diet produces a significant decrease the host resistance in situations of immunosuppression. On the contrary, the AO and AG diets show major efficiency in the elimination of L. monocytogenes and major immunological advantages in immunosuppressed mice. Treatment with RB6-8C5, produces a reduction in the survival of the mice in all groups studied, which leads us to establish that granulocytes play a key role in the control of infection.