Po2 changes in tendon and the synovial fluid of the rabbit hindlimbs during hypoxia and muscle exercise / 体力科学

ABSTRACT

In addition to the histological study of tendon blood circulation, high level of resting blood flows have been functionally observed in the in-vivo tendon tissue preparation. Interest has been directed to investigate the phenomenon from the measurement of tendon tissue Po2 changes which may indicate the activity of capillary blood flow. Simultaneous measurements were done in tendon synovial fluid, tendon and muscle tissues of the 15 rabbit hindlimbs, in conditions of hypoxia and hyperoxia. Continuous measurements of tissue Po<SUB>2</SUB> were performed by polarographic method using a pair of the wire platinum electrode (80μm in diameter) with polymer membrane to the indifferent silver electrode. Average Po<SUB>2</SUB> of tendon synovial fluid, tendon fiber and muscle tissues at rest (mean±SD, n) were 37.36±24.32 (10), 30.96±14.72 (10) and 19.54±8.05 (8), respectively. These data increased gradually to the maximal level of 45.46±27.46 (10), 39.23±16.23 (10) and 25.96±9.77 (8) after cutting of sciatic nerve. Reactive hyperemia-like Po<SUB>2</SUB> increase immediately after release of femoral arterial occlusion was observed neither in tendon synovial fluid nor in tendon tissue. There was no significant difference between each other of tissues in the process of Po<SUB>2</SUB> increase during oxygen intake and the decrease after cessation of oxygen flushing. During exercise, a marked decrease of Po2 was obtained in muscle, but not in tendon synovial fluid.<BR>These data indicate that high level of Po<SUB>2</SUB> in tendon and the surrounding tissuse may have some oxygen supply channels including segmental blood supply system with a short length of and/or a large size of capillary.