Search

This study describes a co-culture system to produce a spheroid comprising rat hepatocytes and non-parenchymal cells by using a microchip consisting of 672 circular microwells (diameter, 300 μm; depth, 200 μm) on a polymethyl methacrylate plate. On inoculation of a suspension comprising rat hepatocytes and non-parenchymal cells, uniform co-cultured spheroids were formed in each microwell. Furthermore, the spheroid conformation and the albumin-secretory activity of the hepatocytes were stably maintained by increasing the proportion of non-parenchymal cells in the co-cultured spheroids. Our findings show that this co-culture system is a promising tool for use in biological research, pharmacokinetics, and toxicity assays.

This study describes a technique for micropatterning rat hepatocytes using a micro stencil. A poly-dimethylsiloxane (PDMS) microstencil, in which a thin membrane comprising 724 through-microholes (500 μm in diameter) in a triangle arrangement of 800 μm pitch was sealed onto the surface of glass plate (24 × 24 mm), was used as a microstencil chip. The surface of the microstencil chip was coated with type IV collagen in order to encourage cell adhesion. Rat hepatocytes micropatterned on the chip by the stencil were peeled off from the chip. The micropatterned conformation of rat hepatocytes on the chip was maintained for at least 5 days of culture. Furthermore, the albumin section and ammonia removal activities of hepatocytes in the micropatterned culture were higher than those in randomly distributed culture. This simple technique for a micropatterned culture may be applicable as a cellular platform for cell-based assay systems.

Primary hepatocytes of rats and dogs formed spheroids in the pores of Polyurethane foam (PUF) used as a culture substratum. The hepatocytes in monolayer and spheroid cultures of stationary state converted lidocaine to monoethylglycinexylidide (MEGX) which was N-deethylation of lidocaine. These metabolic activities of the hepatocytes/spheroid stationary culture system were 1.5∼2.0-fold higher than those of the hepatocyte monolayer culture for 10 days. Consequently, PUF/spheroid culture maintained high drug metabolizing activity for more than 10 days and seems to be promising as a drug metabolism simulator which will be used for cytotoxicity tests and drug screening.