Objective: 

Recent studies have demonstrated that not only obesity but, also the diet could modulate the immune response and contributes to the pathogenesis of immune-mediated diseases. The aim of this study was to determine if and to what extent the high fat diet (HFD) could modulate the development of allergic lung diseases.

Methods: 

OR-CD (obese resistant) rats were sensitized against ovalbumin and divided into 2 groups: group I was fed a standard rat chow diet (12% calories as fat) and group II was fed a HFD (32.5% of calories as fat). The specific airway resistance (sRaw), cellularity of bronchoalveolar lavage fluid (BAL), antioxidant status and lung histological aspects were comparatively assessed on both rats groups.

Results: 

There was no significant difference between the body weights of rats from both groups. On HFD rats both the sRaw increased in response to aerosolized acetylcholine and the total number of cells recovered in BAL fluid were significantly higher. Histological examination revealed that HFD increased infiltration of inflammatory cells on the walls of lobar and segmental bronchi and in peribronchiolar space from this level. Plasma total antioxidant capacity decreased with more than 70% on HFD group.

Conclusions: 

The HFD had unfavourable effects on both the hyperactivity and inflammation related with OVA sensitization. These effects appeared to be mediated, by increasing of oxidant-antioxidant imbalance associated to pulmonary allergic disease.