Increased immune response in mice consuming rice bran oil.
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.
Sierra
Saleta
S
Immunology and Animal Science Dept., Puleva Biotech SA, Camino de Purchil 66, 18004, Granada, Spain.
Lara-Villoslada
Federico
F
Olivares
Mónica
M
Jiménez
Jesús
J
Boza
Julio
J
Xaus
Jordi
J
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D001522:Behavior, Animal; D002478:Cells, Cultured; D004032:Diet; D005227:Fatty Acids / Q000008:administration & dosage; D007109:Immunity; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D019301:Oleic Acid / Q000008:administration & dosage; D012275:Oryza / Q000737:chemistry*; D010666:Phenylpropionates / Q000008:administration & dosage; D010938:Plant Oils / Q000008:administration & dosage*; D000074242:Sunflower Oil; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology
D005227:Fatty Acids; D010666:Phenylpropionates; D010938:Plant Oils; D000074242:Sunflower Oil; D019301:Oleic Acid; C013172:gamma-oryzanol
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