Effects of delta-tocotrienol on inflammation in Neuro-2A cells

Background: Chronic neuroinflammation plays a central role in the development of neurodegenerative diseases, such as Alzheimer’s disease. Like many chronic diseases, Alzheimer’s disease has no cure and there are only minimally effective FDA-approved treatments. A vitamer of vitamin E, tocotrienols have been shown to possess potent anti-inflammatory and antioxidant properties. There are limited studies that investigate tocotrienols on neuroinflammation.

Objectives: Our study aimed to determine the effects of δ-tocotrienol on neuroinflammation and to examine the mechanism of action of δ-tocotrienol in Neuro2A (N2A) cells.

Methods: There were four treatment groups: CON-VEH (control media + vehicle), CON-TT (control media + δ- tocotrienol), CM-VEH (conditioned media + vehicle), and CM-TT (conditioned media + δ-tocotrienol). N2A cells were pretreated with vehicle or 10 μM δ-tocotrienol for 6-8 hours. To induce inflammation, a combination of lipopolysaccharide (LPS) and conditioned media from activated macrophages was used. After the 6-8 hour pretreatment with vehicle or δ-tocotrienol, cells were treated with control media or macrophage conditioned media along with vehicle or δ-tocotrienol for 16-18 hours. Protein was extracted, quantified, and separated via SDS- PAGE. Components of the inflammatory signaling pathway, including phosphorylated and total STAT3, phosphorylated and total NF-κB, and phosphorylated and total IκBα were measured. One-way ANOVA and Tukey’s multiple comparison test were used for data analysis.

Results: CM increased NF-κB phosphorylation, however, TT had no effect. Similarly, CM. increased STAT3 phosphorylation at tyrosine705, and TT had no effect. Neither CM nor TT affected IκBα phosphorylation or total STAT3.