Microcarrier-attached rat hepatocytes as a xenobiotic-metabolizing system in cocultures.

A method for the primary culture of rat liver cells on collagen-coated dextran microcarriers is described. Ethoxycoumarin deethylase (EOD) activity 24 hr after inoculation was comparable for liver cells cultured on microcarriers and on collagen-coated dishes. Cells were cultured on microcarriers for up to 48 hr and retained 25% of the initial EOD-activity that was seen in freshly isolated liver cells. Microcarrier-attached hepatocytes were cocultured with BALB/c 3T3 cells to study the metabolism-mediated cytotoxicity of cyclophosphamide (CPA). In the absence of hepatocytes, growth of 3T3 cells was not affected by CPA at concentrations up to 3600 microM. In coculture with hepatocytes, cytotoxicity of CPA was expressed in a time- and concentration-dependent manner. At high concentrations, CPA slightly depressed the EOD-activity of hepatocytes. Our results indicate that cocultivation of microcarrier-attached rat liver cells with target cells represents a valuable approach to the study of the metabolism-mediated toxicity of xenobiotics in vitro.