Examples of blood flow monitoring and corresponding artery structure. Comparison between blood flow (A-C) and morphology of murine femoral perpendicular cross-sections (C,E) and longitudinal section (F, parallel to flow from deionized water; A, solvent control; B-C, FeCl3-treated mice). Both cross-sections were from the middle of the FeCl3 application area. (A) Mock-treated sample showing underlying intima (pale, low staining circumferential ring). Blue arrows indicate the folded smooth muscle layer, and red arrows indicate RBC inside the arterial lumen. The inset is zoomed out in Figure 3A. (B) The upper bar marks the FeCl3 application site. White arrows point to flattened endothelial layer indicative of vascular damage; black arrows point to normal corrugated/folded endothelial layer; and blue arrows point to the smooth muscle layer. The arterial lumen itself is filled by a platelet-rich clot. The insets are zoomed out in panels B, C, and D, respectively. (C) Blood flow in the femoral artery was monitored and measured with a transit-time perivascular flowmeter and sonic probe. Arrows indicate the timing of the mock treatment. The initial segment was the flow signal detected before the mock treatment. The flow probe signal dropped out as fluid in the vessel’s surroundings was removed to prevent mock dilution. Fluid was reintroduced upon removal of the mock filter paper, and the flow probe again became functional. Following mock application, ∼20 minutes of probe flow signal data were collected. No dip in flow signal following treatment indicates no occlusion. (D) In this instance, FeCl3 was used instead of deionized water. A complete cessation of the blood flow signal with FeCl3 treatment indicates an occlusive clot. At this image zoom, the pockets of loosely adherent platelets are most obvious in the longitudinally section sample in panel F.
