Molecular Mechanisms for the Modulation of Selected Inflammatory Markers by Dietary Rice Bran Oil in Rats Fed Partially Hydrogenated Vegetable Fat

Industrially produced partially hydrogenated
vegetable fat (PHVF) contains trans fatty acids (TFA)
mostly comprising elaidic acid (EA, 18:1Δ9t). Though,
the harmful effects of TFA on health have been repeatedly
publicized, the fat containing TFA have been continued
to be used as a cooking medium in many regions
of the world. The adverse effects of PHVF on oxidative
stress and inflammatory markers and the possible ameliorative
action of rice bran oil (RBO) on these markers
were evaluated. Weaning rats were fed a AIN-93 purified
diet supplemented with the following lipids: groundnut
oil (GNO, 10 wt%), PHVF (10 wt%), RBO (10 wt%),
PHVF blended with RBO at 2.5, 5.0 and 7.5 wt% levels.
The final concentration of the lipids in the diet was maintained
at 10 wt%. Rats were fed these diets for 60 days.
They were sacrificed and analyzed for oxidative stress
and inflammatory markers. The rats fed PHVF showed
lower levels of lipid peroxidation and hepatic antioxidant
enzymes. The rats fed PHVF-containing diets showed
enhanced levels of interleukin-1β, C-reactive proteins
and also showed enhanced levels of paw inflammation
when injected with carrageenan as compared to rats given
GNO, RBO or PHVF blended with incremental amounts
of RBO. The macrophages from rats fed diet containing
PHVF showed up-regulation in the expressions of cytosolic
phospholipase A2 (cPLA2), nuclear factor-κB p65,
toll like receptor (TLR)-2, TLR-4 and down-regulation
in the expressions of peroxisome proliferator activated
receptor gamma (PPAR)γ, adiponectin receptor (AdipoR)-
1 and AdipoR-2 when compared to rats fed diet
containing GNO, RBO and PHVF blended with RBO. It
was concluded that dietary PHVF enhance pro-inflammatory
markers which can be reduced by judiciously blending
PHVF with RBO.