McClatchey Penn Mason, Mignemi Nicholas A, Xu Zhengang, Williams Ian M, Reusch Jane E B, McGuinness Owen P, Wasserman David H
Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee.
Division of Endocrinology, University of Colorado Medical School, Aurora, Colorado.
Microcirculation. 2018 Aug;25(6):e12482. doi: 10.1111/micc.12482. Epub 2018 Jul 15.
Changes in microvascular perfusion have been reported in many diseases, yet the functional significance of altered perfusion is often difficult to determine. This is partly because commonly used techniques for perfusion measurement often rely on either indirect or by-hand approaches.
We developed and validated a fully automated software technique to measure microvascular perfusion in videos acquired by fluorescence microscopy in the mouse gastrocnemius. Acute perfusion responses were recorded following intravenous injections with phenylephrine, SNP, or saline.
Software-measured capillary flow velocity closely correlated with by-hand measured flow velocity (R = 0.91, P < 0.0001). Software estimates of capillary hematocrit also generally agreed with by-hand measurements (R = 0.64, P < 0.0001). Detection limits range from 0 to 2000 μm/s, as compared to an average flow velocity of 326 ± 102 μm/s (mean ± SD) at rest. SNP injection transiently increased capillary flow velocity and hematocrit and made capillary perfusion more steady and homogenous. Phenylephrine injection had the opposite effect in all metrics. Saline injection transiently decreased capillary flow velocity and hematocrit without influencing flow distribution or stability. All perfusion metrics were temporally stable without intervention.
These results demonstrate a novel and sensitive technique for reproducible, user-independent quantification of microvascular perfusion.
许多疾病中都有微血管灌注变化的报道，但灌注改变的功能意义往往难以确定。部分原因是常用的灌注测量技术通常依赖间接或手工方法。
我们开发并验证了一种全自动软件技术，用于测量小鼠腓肠肌荧光显微镜采集视频中的微血管灌注。静脉注射去氧肾上腺素、硝普钠或生理盐水后记录急性灌注反应。
软件测量的毛细血管流速与手工测量的流速密切相关（R = 0.91，P < 0.0001）。软件估算的毛细血管血细胞比容也与手工测量结果基本一致（R = 0.64，P < 0.0001）。检测限为0至2000μm/s，静息时平均流速为326±102μm/s（均值±标准差）。注射硝普钠可使毛细血管流速和血细胞比容短暂增加，并使毛细血管灌注更稳定、更均匀。注射去氧肾上腺素在所有指标上产生相反的效果。注射生理盐水可使毛细血管流速和血细胞比容短暂降低，但不影响血流分布或稳定性。所有灌注指标在无干预情况下随时间保持稳定。
这些结果证明了一种用于微血管灌注可重复、独立于用户的定量分析的新颖且灵敏的技术。
