Protective effect of soybean oil- or fish oil-rich diets on allergic airway inflammation.
BACKGROUND
The increased prevalence of asthma and allergic diseases in westernized societies has been associated with increased intake of diets rich in n-6 fatty acids (FAs) and poor in n-3 FAs. This study aimed to analyze the prophylactic effects of treatment with a soybean oil-rich diet (rich in n-6) or fish oil (rich in n-3) in an allergic airway inflammation model on lung inflammation score, leukocyte migration, T-helper cell (Th)-2 (interleukin [IL]-4, IL-5) and Th1 (interferon [IFN]-γ, tumor necrosis factor-α) cytokines, lipoxin A4, nitric oxide, bradykinin, and corticosterone levels in bronchoalveolar lavage (BAL) or lungs.


METHODS
Male Wistar rats fed with soybean oil- or fish oil-rich diet or standard rat chow were sensitized twice with ovalbumin-alumen and challenged twice with ovalbumin aerosol. The BAL and lungs were examined 24 hours later.


RESULTS
Both diets, rich in n-6 or n-3 FAs, impaired the allergic lung inflammation and reduced leukocyte migration, eosinophil and neutrophil percentages, and IL-4/IL-5/bradykinin levels in BAL and/or lungs, as well as increased the nitric oxide levels in BAL. The soybean oil-rich diet additionally increased the levels of lipoxin A4 and corticosterone in the lungs.


CONCLUSIONS
Data presented demonstrated that the n-6 FA-rich diet had protective effect upon allergic airway inflammation and was as anti-inflammatory as the n-3 FA-rich diet, although through different mechanisms, suggesting that both diets could be considered as complementary therapy or a prophylactic alternative for allergic airway inflammation.
Departamento de Fisiologia, Universidade Federal de São Paulo, Diadema, São Paulo, Brazil.
Roberta Araujo
RA
Navarro-Xavier
Departamento de Fisiologia, Universidade Federal de São Paulo, Diadema, São Paulo, Brazil.
Karina Vieira
KV
de Barros
Departamento de Fisiologia, Universidade Federal de São Paulo, Diadema, São Paulo, Brazil.
Iracema Senna
IS
de Andrade
Departamento de Medicina, Universidade Federal de São Paulo, Diadema, São Paulo, Brazil.
Zaira
Z
Palomino
Departamento de Medicina, Universidade Federal de São Paulo, Diadema, São Paulo, Brazil.
Dulce Elena
DE
Casarini
Departamento de Ciências Biológicas, Universidade Federal de São Paulo, Diadema, São Paulo, Brazil.
Vera Lucia
VL
Flor Silveira
asthma; bradykinin; cytokines; lipoxin A4; n-3 fatty acids; n-6 fatty acids; nitric oxide