Calzavacca Paolo, Evans Roger G, Bailey Michael, Lankadeva Yugeesh R, Bellomo Rinaldo, May Clive N
Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia; Department of Intensive Care and Department of Medicine, Austin Health, Heidelberg, Victoria, Australia; Department of Anesthesia and Intensive Care, AO Melegnano, PO Uboldo, Cernusco sul Naviglio, Italy;
Department of Physiology, Monash University, Clayton, Victoria, Australia; and.
Am J Physiol Regul Integr Comp Physiol. 2015 May 15;308(10):R832-9. doi: 10.1152/ajpregu.00515.2014. Epub 2015 Mar 11.
The role of renal cortical and medullary hypoxia in the development of acute kidney injury is controversial, partly due to a lack of techniques for the long-term measurement of intrarenal oxygenation and perfusion in conscious animals. We have, therefore, developed a methodology to chronically implant combination probes to chronically measure renal cortical and medullary tissue perfusion and oxygen tension (tPO2) in conscious sheep and evaluated their responsiveness and reliability. A transit-time flow probe and a vascular occluder were surgically implanted on the left renal artery. At the same operation, dual fiber-optic probes, comprising a fluorescence optode to measure tPO2 and a laser-Doppler probe to assess tissue perfusion, were inserted into the renal cortex and medulla. In recovered conscious sheep (n = 8) breathing room air, mean 24-h cortical and medullary tPO2 were similar (31.4 ± 0.6 and 29.7 ± 0.7 mmHg, respectively). In the renal cortex and medulla, a 20% reduction in renal blood flow (RBF) decreased perfusion (14.6 ± 8.6 and 41.2 ± 8.5%, respectively) and oxygenation (48.1 ± 8.5 and 72.4 ± 8.5%, respectively), with greater decreases during a 50% reduction in RBF. At autopsy, minimal fibrosis was observed around the probes. In summary, we have developed a technique to chronically implant fiber-optic probes in the renal cortex and medulla for recording tissue perfusion and oxygenation over many days. In normal resting conscious sheep, cortical and medullary tPO2 were similar. The responses to and recovery from renal artery occlusion, together with the consistent measurements over a 24-h period, demonstrate the responsiveness and stability of the probes.
肾皮质和髓质缺氧在急性肾损伤发生发展中的作用存在争议，部分原因是缺乏在清醒动物中长时间测量肾内氧合和灌注的技术。因此，我们开发了一种方法，用于在清醒绵羊体内长期植入组合探头，以长期测量肾皮质和髓质组织灌注及氧分压（tPO2），并评估其反应性和可靠性。将一个渡越时间血流探头和一个血管阻塞器手术植入左肾动脉。在同一次手术中，将双光纤探头插入肾皮质和髓质，该探头包括一个用于测量tPO2的荧光光极和一个用于评估组织灌注的激光多普勒探头。在恢复后的清醒绵羊（n = 8）呼吸室内空气时，皮质和髓质的平均24小时tPO2相似（分别为31.4 ± 0.6和29.7 ± 0.7 mmHg）。在肾皮质和髓质中，肾血流量（RBF）降低20%会导致灌注分别降低（分别为14.6 ± 8.6%和41.2 ± 8.5%）和氧合降低（分别为48.1 ± 8.5%和72.4 ± 8.5%），当RBF降低50%时降低幅度更大。尸检时，在探头周围观察到最小程度的纤维化。总之，我们开发了一种在肾皮质和髓质中长期植入光纤探头以记录组织灌注和氧合情况达数天的技术。在正常静息的清醒绵羊中，皮质和髓质的tPO2相似。对肾动脉阻塞的反应及恢复情况，以及24小时内的一致测量结果，证明了探头的反应性和稳定性。
