Maintenance of liver functions in rat hepatocytes cultured as spheroids in a rotating wall vessel.

Rat hepatocytes were cultured initially as spheroids on culture plates and then transferred into a rotating wall vessel (high-aspect ratio vessel [HARV]) for further culturing. Morphological evaluation based on electron microscopy showed that hepatocyte spheroids cultured for 30 d in the HARV had a compact structure with tight cell-cell junctions, numerous smooth and rough endoplasmic reticulum, intact mitochondria, and bile canaliculi lined with microvilli. The viability and differentiated properties of the hepatocytes cultured in the HARV were further substantiated by the presence of both phase I oxidation and phase II conjugation drug-metabolizing enzyme activities, as well as albumin synthesis.