Rebaudioside A administration prevents experimental liver fibrosis: an in vivo and in vitro study of the mechanisms of action involved.

Rebaudioside A (Reb A) is a diterpenoid isolated from the leaves of Stevia rebaudiana (Bertoni) that has been shown to possess pharmacological activity, including anti-inflammatory and antioxidant properties. However, the ability of Reb A to prevent liver injury has not been evaluated. Therefore, we aimed to study the potential of Reb A (20 mg/kg; two times daily intraperitoneally) to prevent liver injury induced by thioacetamide (TAA) administration (200 mg/kg; three times per week intraperitoneally). In addition, cocultures were incubated with either lipopolysaccharide or ethanol. Antifibrotic, antioxidant and immunological responses were evaluated. Chronic TAA administration produced considerable liver damage and distorted the liver parenchyma with the presence of prominent thick bands of collagen. In addition, TAA upregulated the expression of α-smooth muscle actin, transforming growth factor-β1, metalloproteinases 9, 2 and 13, and nuclear factor kappaB and downregulated nuclear erythroid factor 2. Reb A administration prevented all of these changes. In cocultured cells, Reb A prevented the upregulation of genes implicated in fibrotic and inflammatory processes when cells were exposed to ethanol and lipopolysaccharide. Altogether, our results suggest that Reb A prevents liver damage by blocking oxidative processes via upregulation of nuclear erythroid factor 2, exerts immunomodulatory effects by downregulating the nuclear factor-κB system and acts as an antifibrotic agent by maintaining collagen content.