A method for measuring the oxygen consumption of intact cell monolayers

This report describes an open-air method for measuring the O-2 consumption (Q) over dot O-2) of intact monolayers of cultured cells. This method is ba sed on Fick's second law of diffusion. It requires only a micromanipulator and a miniature O-2 electrode to measure the Po-2, gradient in the culture medium in the well. It was compared with the conventional oxygraph chamber method. Both methods gave the same value for (Q) over dot O-2 in freshly is olated rat type II cells: 166 +/- 15.3 nmol . h(-1). 10(6) cells(-1) for th e open-air method and 151 +/- 11.6 nmol . h(-1). 10(6) cells(-1) for the ox ygraph chamber method (n = 11 experiments). But the open-air method gave si gnificantly larger values for (Q) over dot O-2 in cells cultured for 2 days (236 +/- 8.8 nmol . h(-1). 10(6) cells(-1)) than the oxygraph method (71 /- 15.2 nmol . h(-1). 10(6) cells(-1); P < 0.001; n = 12 experiments). This suggests that the way cells are detached from their substratum to be place d in the oxygraph chamber affects their Q (2). The open-air method may be u seful for studies on the metabolic properties of monolayers because the cel ls do not risk being damaged.