Bioactivation and toxicity of acetaminophen in a rat hepatocyte micropatterned coculture system.

We have recently shown that primary rathepatocytesorganizedinmicropatternedcocultures with murine embryonic fibroblasts (HepatoPac TM ) maintain high levels of liver functions for at least 4 weeks. In this study, rat HepatoPac was assessed for its utility to study chemical bioactivation and associ- ated hepatocellular toxicity. Treatment of HepatoPac cultures with acetaminophen (APAP) over a range of concentrations (0-15 mM) was initiated at 1, 2, 3, or 4 weeks followed by the assessment of morpho- logical and functional endpoints. Consistent and re- producible concentration-dependent effects on hepa- tocyte structure, viability, and basic functions were observedoverthe4-weekperiod,andwereexacerbated by depleting glutathione using buthionine sulfox- imine or inducing CYP3A using dexamethasone, pre- sumably due to increased reactive metabolite-induced stress and adduct formation. In conclusion, the results from this study demonstrate that rat HepatoPac rep- resents a structurally and functionally stable hepatic model system to assess the long-term effects of bioac- tivated compounds. C 2013 Wiley Periodicals, Inc. J Biochem Mol Toxicol 27:471-478, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.21512