Interaction between hepatocytes and collagen gel in hollow fibers

Gel entrapment culture of primary mammalian cells within collagen gel is one important configuration for construction of bioartificial organ as well as in vitro model for predicting drug situation in vivo. Gel contraction in entrapment culture, resulting from cell-mediated reorganization of the extracellular matrix, was commonly used to estimate cell viability. However, the exact influence of gel contraction on cell activities has rarely been addressed. This paper investigated the gel contraction under varying culture conditions and its effect on the activities of rat hepatocyte entrapped in collagen gel within hollow fibers. The hepatocyte activities were reflected by cell viability together with liver-specific functions on urea secretion and cytochrome P450 2E1. Unexpectedly, no gel contraction occurred during gel entrapment culture of hepatocyte under a high collagen concentration, but hepatocytes still maintained cell viability and liver-specific functions at a similar level to the other cultures with normal gel contraction. It seems that cell activities are unassociated with gel contraction. Alternatively, the mass transfer resistance induced by the combined effect of collagen concentration, gel contraction and cell density could be a side effect to reduce cell activities. The findings with gel entrapment culture of hepatocytes would be also informative for the other cell culture targeting pathological studies and tissue engineering.