Suppressive effects of all-trans retinoic acid on the lipopolysaccharide-stimulated release of tumor necrosis factor-α and nitric oxide by rat Kupffer cells in vitro

Kupffer cells are important in the development of liver injury by producing cytokines and radicals. It is known that all-trans retinoic acid (ATRA) participates in the proliferation and differentiation of cells, and exhibits immunomodulatory and anti-inflammatory properties. We evaluated the in vitro effects of three retinoids, ATRA, retinal and retinol, on the production of tumor necrosis factor-α (TNF-α) and nitric oxide (NO) by the LPS-stimulated rat Kupffer cells. ATRA was the most potent in suppressing the production of TNF-α and NO. The suppressive effect of ATRA on Kupffer cells was concentration-dependent. Results suggest that ATRA may act as an immunomodulator in liver diseases by suppressing the production of TNF-α and NO by Kupffer cells.