title: Microvascular and interstitial PO(2) measurements in rat skeletal muscle by phosphorescence quenching.
abstract: To clarify the transport of O(2) across the microvessels in skeletal muscle, we designed an intravital laser microscope that utilizes a phosphorescence quenching technique to determine both the microvascular and tissue PO(2). After we injected the phosphorescent probe into systemic blood, phosphorescence excited by a N(2)-dye pulse laser was detected with a photomultiplier over a 10 microm in diameter area. In vitro and in vivo calibrations confirmed that the present method is accurate for PO(2) measurements in the range of 7-90 Torr (r = 0.958) and has a rapid response time. This method was then used to measure the PO(2) of microvessels with different diameters (40-130 microm) and of interstitial spaces in rat cremaster muscle. These measurements showed a significant drop in PO(2) in the arterioles after branching (from 74.6 to 46.6 Torr) and the presence of a large PO(2) gradient at the blood-tissue interface of arterioles (15-20 Torr). These findings suggest that capillaries are not the sole source of oxygen supply to surrounding tissue.
authors.affiliation: Department of Biomedical Engineering, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan. shibatam@m.u-tokyo.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Shibata
authors.forename: S
authors.initials: S
authors.lastname: Ichioka
authors.forename: J
authors.initials: J
authors.lastname: Ando
authors.forename: A
authors.initials: A
authors.lastname: Kamiya
mesh_terms: D000818:Animals; D001692:Biological Transport; D005110:Extracellular Space / Q000378:metabolism*; D008163:Luminescent Measurements; D008297:Male; D008833:Microcirculation; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000378:metabolism*; D010100:Oxygen / Q000097:blood / Q000378:metabolism*; D010313:Partial Pressure; D051381:Rats; D017208:Rats, Wistar
chemical_list: D010100:Oxygen