Arteriolar oxygenation in tumour and subcutaneous arterioles: Effects of inspired air oxygen content

Journal Article

Carbogen is thought to be more effective than normobaric oxygen in reducing tumour hypoxia because it may reduce hyperoxic vasoconstriction. In this study, tumour and normal arteriolar diameters were measured simultaneously with perivascular pO during air breathing followed by either carbogen or 100% oxygen to determine whether the action of carbogen is the result of alterations in feeding vessel diameter. Fischer-344 rats bearing dorsal flap window chambers, with or without implanted R3230AC tumours, were the experimental subjects. Arteriolar diameters were measured using optical techniques and perivascular pO was measured using recessed-tip electrodes (3-6 μm tip diameter). Baseline arteriolar pO averaged 30-50% of blood gas pO (mean = 97 mmHg). Both hyperoxic gases increased blood gas pO by 4- to 5-fold, but relative improvements in arteriolar pO were ≤ 2.5 for all arterioles studied. This means that these normobaric high O gases are not very efficient in increasing O delivery to tumours. In addition, improvements in tumour arteriolar pO were transient for both hyperoxic gases. Oxygen and carbogen caused no change and mild vasodilatory responses in tumour arterioles, respectively. Normal arterioles on the other hand, tended toward vasoconstriction by carbogen breathing. Peri-arteriolar pO in tumours increased within the first 5 min of breathing either hyperoxic gas, followed by a decline back toward values seen with air breathing. These results suggest that temporal changes in tumour oxygenation after exposure to carbogen or O may not be due to changes in perfusion. Other factors, such as changes in O consumption rate may be involved. 2 2 2 2 2 2 2 2 2 2 2 2

Duke Authors

Cited Authors

  • Dewhirst, MW; Ong, ET; Rosner, GL; Rehmus, SW; Shan, S; Braun, RD; Brizel, DM; Secomb, TW

Published Date

  • January 1, 1996

Published In

Volume / Issue

  • 74 / SUPPL. XXVII

International Standard Serial Number (ISSN)

  • 0007-0920

Citation Source

  • Scopus