173. Exercise improves host response to Influenza in obese and non-obese mice

Obesity may impair host response to influenza infection. In order to determine whether exercise may improve resistance to infection in an obese host, C57Bl/6 mice were fed either a normal diet or high fat diet for 8 weeks, and were assigned to either exercise or no-exercise treatment. Twenty-four hours after the last exercise session, mice were infected with Influenza A/PR/8/34-H1N1. High-fat-diet mice had significantly greater body fat than normal-diet-mice. The results showed that exercise reduced lung viral titer by day 8-post-infection (p.i.) in both obese and non-obese mice, and resulted in reduced bronchoalveolar lavage (BAL) concentrations of eotaxin, G-CSF, IL-10, MIP-1alpha, MIP-1beta, and RANTES. At day 3-p.i., a significant interaction between diet and exercise treatment was found such that exercise reduced BAL cytokines/chemokines in non-obese mice only. Also, at day 3-p.i. the production of cytokines/chemokines appeared to be impaired in obese non-exercise mice (reduced by ∼50% at a similar viral load). Beta-agonist-stimulate ciliary beat frequency (CBF) increases, a model for mucociliary clearance in the trachea, was decreased in infected vs. uninfected mice. However, stimulated CBF increases were significantly impaired in obese non-exercise mice day 3-p.i. vs. uninfected control mice. Body weight loss was attenuated by exercise in non-obese mice only. In summary, exercise improved host resistance to Influenza infection in obese and non-obese, although the magnitude of improvement was greater in non-obese mice.