Propriétés anti-hépatotoxiques et antivirales (virus de l’hepatite C) de l’extrait aqueux de Desmodium adscendens (Fabaceae) et son effet sur la différenciation des cellules souches en hépatocytes

Abstract

Desmodium adscendens (DA) is an herbaceous plant found in Africa and South America, and is used in traditional medicine against liver diseases. The aim of this work was to evaluate in vitro and/or in vivo anti-hepatotoxic and anti-Hepatitis C Virus (HCV) properties of the aqueous extract of DA and its effect on the differentiation of stem cells into hepatocytes. For the anti-hepatotoxic activity of the extract, a model of hepatotoxicity induced by carbon tetrachloride (CCl4) in rat hepatocytes in primary culture was used. Cell viability tests with 3- (4.5-Dimethylthiazol-2-yl)-2.5-diphenyltetrazolium (MTT) bromide, membrane integrity by measuring the activity of alanine aminotransferase released in the incubation medium and content of malondialdehyde (MDA) were carried out. Inhibitory effects on HCV were achieved using genotype 1b sub-genomic replicon systems and cell culture-derived HCV particles (HCVcc). Infection and replication rates were assessed by measuring luciferase activity and indirect immunofluorescence, respectively. Hepatoprotective effect of DA aqueous extract in albino Wistar rats with liver diseases induced by CCl4 or paracetamol and the monitoring over time of its impact on the expression of markers of stem cells differentiation into hepatocytes were subsequently performed. Regarding hepatoprotective activity, membrane integrity tests via alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) activities and MDA level, antioxidant tests via activities of antioxidant enzymes (CAT, SOD) and reduced glutathione level (GSH) were made. As for the monitoring over time of its impact on hepatocyte production process, the Sox-17 transcription factor was detected by a polyclonal rabbit antibody in an internal region of Sox-17 of human origin and the revelation being made to fluorescein (FITC). Results showed that, DA aqueous extract exhibited cytoprotective effect by protecting rat primary hepatocytes against CCl4-induced hepatotoxicity mainly by inhibiting oxidative damage, increasing the percentage of cell viability, reducing the release of ALT and decreasing the formation of MDA. DA aqueous extract significantly inhibited expression of HCV RNA in sub-genomic 1b replicons and this extract did not induced cytotoxicity for LucUbiNeo-ET cells, up to a concentration of 500 μg / mL. DA significantly modulated the circulating activities of CAT, GSH, AST, ALT and PAL during acute CCl4 or paracetamol damage, thus, reflecting its anti-hepatotoxic potential and identifying it as an antioxidant or scavenger of free radicals through the increase of CAT activity and GSH on one hand; and the decrease of transaminases and ALP activities and TBARS levels on the other hand. The aqueous extract of DA increased the expression of the Sox17 protein in the liver of rats exposed to CCl4 or paracetamol, implying that this extract can stimulate the maturation of cells of the final endoderm (the major cells of the stem cell differentiation pathway into hepatocytes). The aqueous extract of DA has hepatoprotective and hepatocurative potential against the multifaceted damage that can be induced by toxins (CCl4), drugs (paracetamol) or viruses (HCV). These results contribute to the promotion of DA as a potential source of secondary metabolites for the treatment of various forms of hepatitis.