Down-regulation of NF-κB expression by n-3 fatty acid-rich linseed oil is modulated by PPARγ activation, eicosanoid cascade and secretion of cytokines by macrophages in rats fed partially hydrogenated vegetable fat.

Purpose: The industrially produced partially hydrogenated vegetable fat (PHVF) contains trans fatty acid mostly comprising of elaidic acid (18:1 ∆9t). PHVF is used as a cooking medium in Southeast Asian countries. The purpose of this study is to evaluate the effects of dietary PHVF on inflammatory mediators and possible ameliorative effects of n-3 fatty acid (α-linolenic acid, ALA)-rich linseed oil (LSO) on the inflammatory mediators.

Methods: Male Wistar weaning rats were fed AIN-93-purified diet supplemented with one of the following lipids for 60 days, groundnut oil (GNO, 10 wt%), PHVF (10 wt%), LSO (10 wt%), PHVF blended with LSO at 2.5, 5.0 and 7.5 wt% levels. The final fat level in the diet was maintained at 10 wt%.

Results: The macrophages from rats fed PHVF showed higher levels of total cholesterol and free cholesterol as compared to those from rats fed GNO and LSO. Macrophages from rats fed PHVF down-regulated the expression of PPARγ and up-regulated the expressions of cytosolic phospholipase A, cyclooxygenase-2, 5-lipoxygenase and nuclear factor-kappa B p65. The macrophages from rats fed PHVF secreted higher levels of pro-inflammatory eicosanoids and cytokines. The rats fed PHVF blended with LSO at incremental amounts showed a significant reduction in the expressions of pro-inflammatory markers in dose-dependent manner.

Conclusion: Detrimental effects of dietary PHVF in enhancing pro-inflammatory agents in rats could be significantly reduced by providing ALA (n-3 PUFA)-rich LSO.