Failure of perfusion with oxygenated Krebs-Ringer solution to preserve the eccrine function of the vascular endothelium in bone
✍ Scribed by Christopher G. Moran; Dr. Michael B. Wood
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 464 KB
- Volume
- 10
- Category
- Article
- ISSN
- 0736-0266
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✦ Synopsis
Abstract
An ex vivo canine tibia preparation was perfused at a constant rate with aerated (95% O~2~‐5% CO~2~) Krebs‐Ringer solution for 24 h. Bolus injections of norepinephrine (0.125‐0.5 μg) were given and then acetylcholine (5 × 10^−5^ M) was used to stimulate endothelial production of smooth muscle relaxing factors. Following 1 h of perfusion the addition of acetylcholine resulted in significant attenuation of the response to norepinephrine (p < 0.001). After 4 h perfusion acetylcholine did not attenuate the norepinephrine response, but addition of I‐arginine (the precursor of endothelial‐derived relaxing factor) resulted in significant attenuation in the presence of acetylcholine (p < 0.005). At 6, 12, and 24 h the acetylcholine did not attenuate the norepinephrine response. It is concluded that normothermic, continuous perfusion with oxygenated Krebs‐Ringer solution results in normal endothelial eccrine activity up to 1 h. Following this period there is substrate depletion but endothelial eccrine function can be demonstrated for up to 4 h. At 6 h this function cannot be demonstrated, suggesting degradation of the functional integrity of the endothelium.