Fig. 1
Incomplete retinal microcirculatory reperfusion after ischemia. a The illustration depicts the placement of a small strip (0.3 × 1 mm) of 20% FeCl3–saturated filter paper over the optic nerve for 3 min to produce retinal ischemia by occluding the central retinal artery (CRA). ACA: anterior cilliary artery, LPCA: long posterior cilliary artery. b The diagram depicts in vivo ischemia/recanalisation experiments and preparation of retinae for ex vivo studies. c Raw (black and white) and relative (pseudo-colored) laser speckle contrast (LSC) images recorded within the first 10 min after FeCl3 application (upper row) or within 35 min of tPA infusion (lower row) show progress of retinal ischemia and reperfusion after recanalisation. Time (minutes) elapsed after FeCl3 placement is indicated on each panel. The relative LSC images at the end of each row were generated by comparing the raw image to the first images in each row to illustrate the relative changes in retinal blood flow. Cold colors (blue) depict a decrease, whereas hot colors (yellow, red) represent an increase in blood flow relative to the beginning of ischemia or tPA infusion. Note the blood flow decrease in vessels as well as retina during ischemia. d Illustrates the typical retinal blood flow drop measured in a mouse from 3 non-overlapping randomly selected region of interests over the retina within 10 min after induction of clot formation by FeCl3 in the central retinal artery as detected by LSC imaging. Red dots represent the individual measurements obtained every 10 s, and the red line and shaded area illustrate the mean and its standard deviation, respectively. e Illustrates the retinal blood flow recovery within 35 min following the beginning of tPA infusion relative to the maximum flow drop during ischemia. f-h In vivo fluorescence retinal angiograms obtained with infusion of FITC–dextran-70S (i.v.) before (pre-ischemia) (f) or during ischemia (g), and after successful recanalisation (h). Note less intense fluorescence emission from the retinal tissue (square) and draining venules (v1, v2) after recanalisation despite re-filling of the retinal arterioles (a1, a2), suggesting impaired microcirculatory reflow