Techniques for Measurement of Oxygen Consumption Rates of Hepatocytes during Attachment and Post-Attachment

Abstract

Three techniques for measuring oxygen consumption rate (OCR) of cultured cells relevant to the development of bioartificial liver devices are reported. In an oxystat apparatus, HepG2 cells immobilised on Cytodex 3 microcarriers at a concentration of 10⁶ cells ml^-1 had a mean OCR of 0.7 nmol s^-1/10⁶ cells. The OCR decreased with increasing cell density, a characteristic previously reported for other cell lines. Rat hepatocytes immobilised on single collagen layers in a flow cell and challenged with ammonia had a mean OCR of 0.59 nmol s^-1/10⁶ cells. A novel two-compartment oxystat system was used to determine the OCR of rat hepatocytes during the attachment phase. OCR declined from 1.0 nmol s^-1/10⁶ immediately after seeding to 0.7 nmol s^-1/10⁶ cells at nine hours. The low OCR for HepG2 reflects loss of certain oxygen dependent metabolic pathways. The OCR measured for rat hepatocytes during and post-attachment are significantly higher than those reported elsewhere and have major implications for the development of bioartificial liver devices.