Anetzberger H, Thein E, Becker M, Walli A K, Messmer K
Department of Orthopaedics, Ludwig-Maximilians University, 81377 Munich, Germany.
J Appl Physiol (1985). 2003 Sep;95(3):1153-8. doi: 10.1152/japplphysiol.00299.2003. Epub 2003 May 2.
In this study, we compared bone blood flow values obtained by simultaneously injected fluorescent (FM) and radiolabeled microspheres (RM) at stepwise reduced arterial blood pressure. Ten anesthetized female New Zealand White rabbits received simultaneous left ventricular injections of FM and RM at 90, 70, and 50 mmHg mean arterial blood pressure (MAP). After the experiments, both kidneys and long bones of all four limbs were removed and dissected in a standardized manner. Radioactivity (corrected for decay, background, and spillover) and fluorescence were determined, and blood flow values were calculated. Relative blood flow values estimated for each bone sample by RM and FM were significantly correlated (r = 0.98, slope = 0.99, and intercept = 0.04 for 90 mmHg; r = 0.98, slope = 0.94, and intercept = 0.09 for 70 mmHg; r = 0.98, slope = 0.96, and intercept = 0.07 for 50 mmHg). Blood flow values (ml x min-1 x 100 g-1) of right and left bone samples determined at the different arterial blood pressures were identical. During moderate hypotension (70 mmHg MAP), blood flow in all bone samples remained unchanged compared with 90 mmHg MAP, whereas a significant decrease of bone blood flow was observed at severe hypotension (50 mmHg MAP). Our results demonstrate that the FM technique is valid for measuring bone blood flow. Differences in bone blood flow during altered hemodynamic conditions can be detected reliably. In addition, changes in bone blood flow during hypotension indicate that vasomotor control mechanisms, as well as cardiac output, play a role in setting bone blood flow.
在本研究中，我们比较了在逐步降低动脉血压时通过同时注射荧光微球（FM）和放射性标记微球（RM）所获得的骨血流值。十只麻醉的雌性新西兰白兔在平均动脉压（MAP）为90、70和50 mmHg时接受了左心室同时注射FM和RM。实验结束后，切除所有四肢的双肾和长骨，并以标准化方式进行解剖。测定放射性（校正衰变、本底和溢出）和荧光，并计算血流值。RM和FM估计的每个骨样本的相对血流值显著相关（90 mmHg时，r = 0.98，斜率 = 0.99，截距 = 0.04；70 mmHg时，r = 0.98，斜率 = 0.94，截距 = 0.09；50 mmHg时，r = 0.98，斜率 = 0.96，截距 = 0.07）。在不同动脉血压下测定的左右骨样本的血流值（ml·min⁻¹·100 g⁻¹）相同。在中度低血压（70 mmHg MAP）期间，与90 mmHg MAP相比，所有骨样本的血流保持不变，而在严重低血压（50 mmHg MAP）时观察到骨血流显著减少。我们的结果表明，FM技术可有效测量骨血流。在血流动力学条件改变期间骨血流的差异能够可靠地检测到。此外，低血压期间骨血流的变化表明，血管舒缩控制机制以及心输出量在设定骨血流中起作用。
