Novel video method for acquiring and modeling in vivo hemodynamic data from arteriolar networks of rat gluteus maximus skeletal muscle

Experiment based mathematical models of skeletal muscle arteriolar hemodynamics are currently limited. Thus, we developed a skeletal muscle preparation to acquire in vivo hemodynamic data across arteriolar networks to compare to a steady‐state computational flow model. Our rat gluteus maximus muscle preparation enabled complete evaluation of microvascular networks (feed artery to capillary network) within the same focal plane. Using fluorescently labeled RBCs, we developed a novel means to measure single RBC velocities across arteriolar lumens. In vivo velocity profiles were fit to quadratic curves and used to calculate flow and RBC velocity ratios (Vmax/Vmean) for 6 vessel segments (diameters: 70 to 117 μm). Mass balance at arteriolar bifurcations and flow calculations at two levels within the same segment had errors of 0.28% and 7.67% respectively. Goodness of fit (r2) of luminal RBC velocities to the quadratic function ranged from 0.82 to 0.87 and velocity ratios ranged from 1.51 to 1.97. Images from arteriolar networks were assembled into photomontages and translated into the flow model. Flow model and experimental values were 80.3±10.3% and 80.5±12.5% congruent for segment flow and segment Vmean respectively. We have a novel method for acquiring in vivo hemodynamic data from skeletal muscle arteriolar networks as a basis for developing computational models. Support: NSERC.