Prophylactic effects of omega-3 polyunsaturated fatty acids and luteolin on airway hyperresponsiveness and inflammation in cats with experimentally-induced asthma.

The aim of this study was to assess the preventive effects of omega-3 polyunsaturated fatty acids (omega3 PUFA) and luteolin supplementation on allergen-induced inflammation in eight Ascaris suum (AS)-sensitised cats. Airway responsiveness (AR) tests were performed and venous blood and bronchoalveolar lavage fluid (BALF) collected before and following a single (AS-stimulated) allergen exposure, as well as at the end of a 4-week treatment period, which was followed by a second AS-challenge. The omega6/omega3 fatty acid ratio in erythrocyte membranes, BALF cytology, AR to carbachol, and BALF lipoxin A(4) (LXA(4)), an endogenous inhibitor of inflammation, were assessed at each time point. Compared to respective unstimulated values, AS-challenged cats exhibited a significant rise in BALF eosinophil percentage and there was a trend to increased BALF total cell counts, increased AR and reduced BALF LXA(4) concentrations. The significant decrease in the blood omega6/omega3 ratio seen after supplementation demonstrated that omega3 PUFA were efficiently absorbed. No changes in BALF cytology were found between untreated and treated AS-stimulated cats, but BALF LXA(4) levels were significantly elevated and AR significantly decreased following supplement intake. The study suggests that omega3-luteolin supplementation may have some beneficial effects on AR through a LXA(4)-dependent pathway in cats with experimentally-induced asthma. Copyright 2009 Elsevier Ltd. All rights reserved.