Sierra S, Lara-Villoslada F, Olivares M, Jiménez J, Boza J, Xaus J. Increased immune response in mice consuming rice bran oil.
Eur J Nutr 2005;
44:509-16. [PMID:
15719157 DOI:
10.1007/s00394-005-0554-y]
[Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2004] [Accepted: 01/05/2005] [Indexed: 10/25/2022]
Abstract
BACKGROUND
Polyunsaturated fatty acids play a key role in a number of biological functions. Rice bran oil (RBO) is rich in linoleic acid, an essential n-6 fatty acid. n-6 fatty acids are said to have proinflammatory effects as a result of an increase in n-6 fatty acid-derived eicosanoids. RBO is also rich in gamma-oryzanol, a compound from the unsaponifiable fraction, with antioxidant properties.
OBJECTIVE
The aim of this work is to examine the effect of RBO-and/or gamma-oryzanol-enriched diets on the regulation of the immune response.
METHODS
4 week-old Balb/C mice were fed diets enriched with either RBO or high oleic-sunflower oil (HOSO), for one month. Serum samples, bone marrow-derived macrophages and lymphocytes from the spleen were collected.
RESULTS
Compared to HOSO, our results show that RBO modulates the immune system by enhancing B-lymphocyte proliferation (6842 +/- 2959 vs 10073 +/- 4186 cpm; HOSO vs RBO; n = 10 per group) and TH1-type cytokines such as IL-2 (55.85 +/- 18.2 vs 101.7 +/- 21.6 pg/ml) or TNF-alpha (49.12 +/- 18.6 vs 184.9 +/- 46.2 pg/ml; HOSO vs RBO) in a significant way (n = 10 per group). Moreover, the reduction found in the TH2 cytokine IL-4 (7.59 +/- 2.3 vs 4.48 +/- 1.6 pg/ml) and IgE (56.9 +/- 39.2 vs 42.4 +/- 35.2 ng/ ml; HOSO vs RBO, n = 10 per group) levels suggests RBO may have antiallergenic properties. To elucidate the role of gamma-oryzanol, a similar study was also carried out including diets enriched with refined RBO or HOSO containing gamma-oryzanol (2 %). Our results suggest that although gamma-oryzanol may modulate the immune system, it is not responsible for the overall immunostimulation effect seen for RBO.
CONCLUSIONS
RBO-enriched diets could be useful in situations where a potentiation of the immune response was required. The fatty acids composition, more than the unsaponifiable fraction, might be responsible for this effect.
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