Long-Term Stable Cultures of Rat Hepatocytes: An in Vitro Model to Study Acute and Chronic Hepatic Inflammation

Abstract

Engineered tissues provide an opportunity to investigate important physiological processes difficult to study in whole perfused organs and animal models. For example, a hepatocyte culture model consisting of rat hepatocytes cultured in a collagen sandwich configuration, which exhibits stable differentiated liver-specific functions, may be useful to investigate liver pathophysiology. To investigate systemic inflammation-related hepatic failure, we chronically exposed hepatocytes to the inflammatory mediators interleukin-1β (IL-1β) and interleukin-6 (IL-6) for up to 4 weeks. IL-6 (2.5 ng/mL) transiently suppressed albumin (-90%) and chronically increased fibrinogen (+6-fold) production. IL-6 inhibited urea synthesis at 2.5 ng/mL and stimulated it at 0.025 ng/mL. IL-1β (10 ng/mL) inhibited albumin (-90%), urea (-40 to 50%), and IL-6-stimulated fibrinogen (-90%) secretion. The inhibitory effect of IL-1β on urea secretion was dose-dependent. Furthermore, IL-1β transiently stimulated nitric oxide (NO) synthesis; however, NO did not mediate the effect of IL-1β on albumin and fibrinogen production, and played a minor role in IL-1β-mediated urea synthesis suppression. In conclusion, IL-1β and IL-6 exert, via a direct effect on hepatocytes, long-term inhibitory effects on hepatic functions that are potentially important for the survival of the host, which may contribute to hepatic dysfunction in prolonged inflammatory states.