Fig. 1

Imaging of skeletal muscle microcirculation. a Example of a single SDF image of rat gastrocnemius microcirculation. b, In each microvessel that fitted the criteria of analysis (a) in focus, b) had a sufficient length and were not close to bifurcation, and c) were continuously filled with RBCs and did not contain plasma gaps) lines were placed ± every 10 µm perpendicular to the vessel direction (as shown by lines in image). c, Schematic illustration of the perfused boundary region (PBR) in relation to the glycocalyx barrier properties in a blood vessel. The PBR covers the cell-permeable part of the glycocalyx, to which RBCs have limited access, while the cell-impermeable part cannot be accessed at all. The PBR is the main readout parameter of the gastrocnemius SDF imaging, and calculated from the median RBC column width (P50) and outer diameter of RBC perfused lumen