[Development of hepatocyte cultures in toxicity testing]

Area of Science:

• Hepatology
• Drug Metabolism
• Toxicology

Background:

• The liver is crucial for drug and xenobiotic metabolism, making liver cell cultures ideal for toxicity testing.
• Standard cell cultures rapidly degrade key metabolic enzymes, limiting their usefulness.
• Maintaining tissue-like oxygen levels and using co-cultures can improve xenobiotic metabolism in vitro.

Purpose of the Study:

• To enhance the maintenance of xenobiotic metabolism in liver cell cultures.
• To investigate the impact of controlled oxygen tension and heterotypic cell cultures on liver cell function.
• To explore ploidy shifts as indicators of chemical-induced toxicity in hepatocytes.

Main Methods:

• Utilized teflon membrane culture dishes to achieve stable, tissue-like oxygen tensions (4% and 13% O2).
• Established co-cultures of hepatocytes with auxiliary cells from young rat livers.
• Analyzed hepatocyte DNA and protein content using flow cytometry to detect ploidy shifts.

Main Results:

• Teflon membrane dishes successfully maintained tissue-like oxygen levels.
• Co-cultures preserved liver-specific cytochrome P-450 dependent aldrin epoxidase activity for up to one week (40% of original).
• Low oxygen, fetal calf serum, phenobarbital, and dimethylsulfoxide induced specific ploidy shifts in hepatocytes.

Conclusions:

• Controlled oxygen tension and co-culturing significantly improve the longevity of xenobiotic metabolism in hepatocyte cultures.
• Chemically induced ploidy alterations in hepatocytes may serve as biomarkers for compounds affecting cell growth and differentiation.
• This enhanced in vitro model offers a more reliable system for drug metabolism and toxicity studies.