Sesame oil lignans inhibit hepatic endoplasmic reticulum stress and apoptosis in high-fat diet-fed mice

- Sesame oil contains a high concentration of lignans.
- Sesame oil suppresses endoplasmic reticulum stress.
- Expressions of apoptotic markers are down-regulated by sesame oil.
- Hepatic triacylglycerol concentration is reduced by sesame oil.
- Lipogenic transcription factor and enzyme are decreased by sesame oil.

The inhibitory effect of lignan-rich sesame oil (SSO) against the endoplasmic reticulum (ER) stress and apoptosis induced by a high-fat diet (HFD) was studied, and its mechanism of action was elucidated in a comparison with soybean oil (SBO), which contains similar unsaturated fatty acid content but has no lignans. The HFD was prepared by adding 20% (w/w) lard (LD), SSO, or SBO to chow diet and provided for 12 weeks. In the SSO group, expression of ER stress and proapoptotic markers were downregulated, compared with levels in the LD group. However, these effects were not observed in the SBO group. The hepatic triacylglycerol concentration and expression of lipogenic enzyme in the SSO group were lower than that in the LD and SBO groups. These results show that SSO is able to decrease HFD-induced ER stress and apoptosis, and these effects were likely caused by its lignan compounds.