Journal: bioRxiv

Article Title: ECgo: All-Optical Induction of Single Endothelial Cell Injury and Capillary Occlusion in the Brain

doi: 10.1101/2025.05.27.656398

Figure Lengend Snippet: (A) Quantification of patent capillaries subjected to irradiation in the presence of Ps2P , either pretreated with anticoagulants to prevent occlusion or post-treated with rtPA to promote recanalization. All treatments failed to prevent blood flow cessation or to restore blood flow, respectively. (B) Reduction in blood flow upon capillary irradiation in the presence of anticoagulant drugs (left): Aspirin (N = 2, n = 10), heparin (N = 3, n = 17), clopidogrel (N = 4, n = 12) or blood flow recovery following reperfusion therapy with rtPA (N = 2, n = 18; right). Points represent single capillaries. (C) Representative two-photon images showing stalled blood cells inside the targeted capillary (left: leukocyte, middle: red blood cells (RBCs), right: platelets). Channels are displayed separately, with the merged image in the top left. Scale bars: 10 μm. (D) Representative maximum intensity two-photon 30-µm-z-projections of a Claudin5-EGFP reporter mouse. White arrowheads indicate individual EC nuclei. Scale bar: 10 μm. (E) Representative two-photon images of an EC injured capillary, showing pre-irradiation EC morphology (left) and post-irradiation damage (right). Line scan kymographs (cyan rectangles) using third-harmonic generation (THG) imaging confirm the presence and absence of blood flow pre- and post-irradiation, respectively. White arrowhead points towards injured EC nuclei. Scale bars: 10 μm. N = number of animals, n = number of capillaries.

Article Snippet: Clopidogrel (Tocris, Cat.# 1820) administration included either a 4-day treatment at a lower dose (20 mg/kg; one i.p. injection per day over 4 d) or a higher single dose injection (100 mg/kg, i.p.) on the capillary irradiation day, with a minimum 3-h waiting period between injection and capillary irradiation.

Techniques: Irradiation, Imaging