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Comparison of tumor and normal tissue oxygen tension measurements using OxyLite or microelectrodes in rodents

2001; American Physical Society; Volume: 280; Issue: 6 Linguagem: Inglês

10.1152/ajpheart.2001.280.6.h2533

1522-1539

Rod D. Braun, Jennifer L. Lanzen, Stacey A. Snyder, Mark W. Dewhirst,

Nitric Oxide and Endothelin Effects

In this study we compare oxygen tension (Po 2 ) histograms measured with O 2 microelectrodes and a new optical Po 2 measurement device, the OxyLite, in normal tissues (mouse spleen and thymus) and in tumors (R3230Ac in rats) ( n = 5–6). The transient response to glucose infusion or 100% O 2 breathing (hyperoxia) was also measured in tumors. Po 2 histograms of spleen and thymus with the two devices were not different. The OxyLite tumor Po 2 histogram, however, was left-shifted compared with the microelectrode (median Po 2 1.0 vs. 4.0 mmHg, P = 0.016). Both probes responded to acute hyperglycemia with a mean increase of 3–6 mmHg, but the microelectrode change was not significant. The OxyLite consistently recorded large Po 2 increases (∼28 mmHg) with hyperoxia, whereas the microelectrode response was variable. The OxyLite averages Po 2 over an area that contains interstitial and vascular components, whereas the microelectrode measures a more local Po 2 . This study demonstrates the importance of considering the features of the measurement device when studying tissues with heterogeneous Po 2 distributions (e.g., tumors).