Oxymini fibre optic oxygen meter

Hypoxic conditions in HUVEC were induced using a modified version of our recently described enzymatic model [36 (link), 75 (link)]. In the present study concentrations of the hypoxia inducing enzymes were adapted to 4 U/ml glucose oxidase (GO), and 120 U/ml catalase (CAT) and cell culture plates were transferred into an airtight chamber, which was flooded with 1 bar, 10 l/min nitrogen gas until oxygen was reduced to 1 %. The box was then kept inside an incubator at 37 °C. Oxygen levels were monitored directly in the culture medium using an OxyMini fibre optic oxygen meter (World Precision Instruments, USA, Sarasota) and OxyMicro Software v.00 04/2003.

Hypoxia was induced by enzymatic oxygen depletion using 4 U/ml glucose oxidase and 120 U/ml catalase as previously described [18 (link)]. For this study, the concentration of hypoxia-inducing enzymes was optimised after measuring oxygen levels in cell culture medium using the OxyMini fibre optic oxygen meter (World Precision Instruments, USA, Sarasota) and OxyMicro Software v.00 04/2003. After hypoxia induction, cell culture plates were put in an airtight chamber (Billups-Rothenberg, Del Mar, CA, USA), flushed with nitrogen until the oxygen concentration was < 1% and kept in the incubator at 37 °C for 24 h.