Epigallocatechin-3-gallate (EGCG) is the main compound of green tea with well-described antioxidant, anti-inflammatory, and tumor-suppressing properties. However, EGCG at high doses was reported to cause liver injury. In this study, we evaluated the effect of EGCG on primary culture of rat hepatocytes and on rat liver mitochondria in permeabilized hepatocytes. The 24-hour incubation with EGCG in concentrations of 10 μmol/L and higher led to signs of cellular injury and to a decrease in hepatocyte functions. The effect of EGCG on the formation of reactive oxygen species (ROS) was biphasic. While low doses of EGCG decreased ROS production, the highest tested dose induced a significant increase in ROS formation. Furthermore, we observed a decline in mitochondrial membrane potential in cells exposed to EGCG when compared to control cells. In permeabilized hepatocytes, EGCG caused damage of the outer mitochondrial membrane and an uncoupling of oxidative phosphorylation. EGCG in concentrations lower than 10 μmol/L was recognized as safe for hepatocytes in vitro.
- MeSH
- čaj chemie metabolismus MeSH
- fluorescenční mikroskopie MeSH
- hepatocyty cytologie účinky léků metabolismus MeSH
- jaterní mitochondrie účinky léků metabolismus MeSH
- kaspasa 3 metabolismus MeSH
- katechin analogy a deriváty toxicita MeSH
- krysa rodu rattus MeSH
- kultivované buňky MeSH
- membránový potenciál mitochondrií účinky léků MeSH
- oxidativní fosforylace účinky léků MeSH
- potkani Wistar MeSH
- reaktivní formy kyslíku metabolismus MeSH
- TNF-alfa metabolismus MeSH
- viabilita buněk účinky léků MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Epigallocatechin-3-gallate (EGCG) is widely used as a weight controlling supplement. Concerns about its safety evoked after cases of hepatotoxicity occurred upon its use. The underlying factors that could be involved in EGCG associated hepatotoxicity are not fully studied. In this study, we investigated the possible impact of lipopolysaccharide (LPS), as an inflammagen, on the effect of EGCG on hepatocytes. HepG2 cells were treated with different concentrations of EGCG (100, 200, 500 μM), with and without LPS (10 nM)-presensitization of the cells. Viability of HepG2 cells decreased with the increased concentrations of EGCG; the viability was even lesser in LPS-presensitized cells. Oxidative stress (Ox.LDL and CXCL16), the expression of nuclear retinoic receptors (RAR, RXR) and the biomarkers of hepatocellular injury (TNFα, TGFβ1) were all relatively higher in LPS-presensitized cells compared to non-sensitized cells upon treatment with EGCG. Sensitization of HepG2 cells with LPS alone did not affect the viability or any of the other biomarkers considered in this study. In conclusion, EGCG alone can be harmful to liver at high concentrations and this effect may become more pronounced under the influence of an inflammagen.
- Klíčová slova
- epigallocatechin-3-gallate (EGCG),
- MeSH
- buňky Hep G2 chemie imunologie účinky léků MeSH
- hepatocyty * chemie imunologie účinky léků MeSH
- katechin * analogy a deriváty farmakologie toxicita MeSH
- polyfenoly farmakologie toxicita MeSH
- techniky in vitro metody statistika a číselné údaje MeSH
- viabilita buněk účinky léků MeSH
- zánět * MeSH
- Publikační typ
- hodnotící studie MeSH
- práce podpořená grantem MeSH
Epigallocatechin gallate (EGCG) is an antioxidant found in green tea. In this study, male Wistar rats were subjected either to partial hepatectomy (PHx), or a sham operation (LAP). Twenty-four hours after surgery, hepatocytes were isolated and treated with various concentrations of EGCG for up to 72 h. We then measured markers of cell viability, oxidative stress, DNA synthesis, and caspase activity. Morphological criteria, cell viability tests, and albumin synthesis revealed toxicity starting at 10 μmol/L. DNA synthesis was higher in hepatocytes isolated from rats after PHx and inhibited by EGCG. Furthermore, EGCG increased the activity of caspases 3 and 7, seen more in hepatocytes from PHx rats. In conclusion, EGCG at a concentration of 10 μmol/L was toxic for hepatocytes isolated from both PHx and LAP rats.
- MeSH
- antioxidancia aplikace a dávkování toxicita MeSH
- DNA biosyntéza MeSH
- hepatektomie * MeSH
- hepatocyty účinky léků enzymologie metabolismus MeSH
- kaspasa 3 metabolismus MeSH
- kaspasa 7 metabolismus MeSH
- katechin aplikace a dávkování analogy a deriváty toxicita MeSH
- krysa rodu rattus MeSH
- oxidační stres účinky léků MeSH
- potkani Wistar MeSH
- primární buněčná kultura MeSH
- viabilita buněk účinky léků MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Epigallocatechin gallate (EGCG) has been shown to be protective in various experimental models of liver injury, although opposite effects have also been reported. Since its effect on biliary physiology has not been thoroughly investigated, the present study evaluated effect of EGCG on bile flow and bile acid homeostasis in rats. Compared to controls, EGCG treatment decreased bile flow by 23%. Hepatic paracellular permeability and biliary bile acid excretion were not altered by EGCG administration, but biliary glutathione excretion was reduced by 70%. Accordingly, the main glutathione transporter on the hepatocyte canalicular membrane, multidrug resistance-associated protein 2 (Mrp2), was significantly decreased at the protein level. EGCG administration also doubled plasma bile acid levels compared to controls. While protein levels of the main hepatic bile acid transporters were unchanged, the rate-limiting enzyme in the bile acid synthesis, Cyp7a1, was significantly increased by EGCG. Enhanced bile acid synthesis in these animals was also confirmed by a 2-fold increase in plasma marker 7α-hydroxy-4-cholesten-3-one. In contrast, EGCG markedly downregulated major bile acid transporters (Asbt and Ostα) and regulatory molecules (Shp and Fgf15) in the ileum. When EGCG was coadministered with ethinylestradiol, a potent cholestatic agent, it did not show any additional effect on the induced cholestasis. This study shows ability of EGCG to raise plasma bile acid concentrations, mainly through Cyp7a1 upregulation, and to decrease bile production through reduction in Mrp2-mediated bile acid-independent bile flow. In conclusion, our data demonstrate that under certain conditions EGCG may induce cholestasis.
- MeSH
- ABC transportéry genetika MeSH
- cholestáza chemicky indukované MeSH
- cholestenony metabolismus MeSH
- cholesterol-7-alfa-hydroxylasa genetika metabolismus MeSH
- down regulace účinky léků MeSH
- ethinylestradiol farmakologie MeSH
- glutathion metabolismus MeSH
- hepatocyty účinky léků metabolismus MeSH
- homeostáza účinky léků MeSH
- ileum účinky léků metabolismus MeSH
- katechin analogy a deriváty toxicita MeSH
- krysa rodu rattus MeSH
- permeabilita MeSH
- potkani Wistar MeSH
- upregulace účinky léků MeSH
- žlučové kyseliny a soli biosyntéza metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- isomerie MeSH
- katechin analogy a deriváty toxicita MeSH
- kuřecí embryo MeSH
- teratogeny škodlivé účinky MeSH
- zvířata MeSH
- Check Tag
- kuřecí embryo MeSH
- zvířata MeSH
- Publikační typ
- srovnávací studie MeSH
