The functional characteristics of tendon blood circulation in the rabbit hindlimbs.

Abstract

Neurohormonal, mechanical, and muscle exercise effects on tendon blood flow were studied in thirty-five rabbits. After anesthesia by urethane, experiments were performed on in situ preparation of the hindlimb under stable state in systemic blood pressure. Tendon and muscle blood flow were measured simultaneously by the hydrogen gas clearance method, and their temperature and Po t were continuously observed by thermocouple and oxygen sensor, respectively. The resting blood flow in the denervated tendon tibialis anterior, gastrocnemius, and soleus (ml/(100 g min)) was 39.0 + 4.0, 34.5 + 8.2, and 30.2 + 4.3, respectively, whereas in their muscles it was 17.8 + 1.5, 17.1 + 2.1, and 12.6 + 1.1, respectively. The tendon tissue temperature and Pot increased gradually until 15-20 min after cutting the sciatic nerve, and the increasing rate depended upon the initial control level before denervation. Intravenous injection of noradrenaline in the dose of 1-9.9 gig/kg produced a marked decrease in the tendon tissue temperature of the tibialis anterior, but a mild one in the muscle. The longitudinal tension force produced a decrease in the tendon tissue temperature of the tibialis anterior, but no change in the muscle. During muscle exercise, tendon blood flow and temperature tended to decrease, whereas the muscle blood flow and temperature increased markedly from the beginning of muscle exercise. There was no evidence to demonstrate the existence of exercise hyperemia in the tendon tissue. These data suggest that tendon blood circulation can be modified by many factors, and that mechanical and exercise effects may play a role in regulation of tendon blood flow channels and fluid transfer for the lubrication of tendon fiber movements.

IGF‐I activates PKB and prevents anoxic apoptosis in Achilles tendon cells

“…Hypoxia may also induce apoptosis through other pathways; for example, one report suggested that hypoxia-induced apoptosis requires the development of acidosis [36], but in our experiments apoptosis occurred with no change in the pH of the medium. In vivo, tendons undergo mechanical strain, and static tension held over several minutes reduces tendon oxygen levels [41]. It is unlikely that tension-induced hypoxia would induce apoptosis in tendons, as periods of complete hypoxia (anoxia) >24 h were required to induce substantial amounts of apoptosis 'in the current study.…”

The effects of reduced oxygen tension on cell proliferation and matrix synthesis in synovium and tendon explants from the rabbit carpal tunnel: an experimental study in vitro

“…Therefore, application of these findings to the pathogenesis of carpal tunnel syndrome may be limited. However, the relevance of testing the low oxygen levels was demonstrated by Takemiya and Maeda [28]. Using an oxygen electrode, in vivo recordings from the rabbit Achilles tendon revealed PO, levels of 4.1 f 2.0 kPa.…”

Heterogeneity of laser Doppler flowmetry in perfused muscle indicative of nutritive and nonnutritive flow

“…In addition, estimations of blood flow for muscle at rest suggested that approximately half of the total flow was nutritive and thus capable of clearing intramuscular injected markers (17). More recent estimates suggest this proportion may be even lower (16,36).…”