Fig. 5
Impaired NIR-II tracer influx in the brain and clearance from the brain. a Schematic illustrating the evaluation of NIR-II tracer distribution using coronal brain sections. The schematic diagram was created by using the online software https://biorender.com. b Representative brain slice images showing uniform tracer distribution in sham mice and uneven distribution in MCAO mice. c Ratio of brain slices, n = 4 per group, t test, P = 0.0098. Colored dot represents the ratio of individual animal. Center is median and quartiles shown by box and whiskers. d Schematic depicting the experiment for evaluating brain clearance levels. The schematic diagram was created by using the online software https://biorender.com. e NIR-II imaging through the intact skull for comparing the remaining NIR-II tracer between the MCAO group and the sham group 6 h post-infusion. White scale bar: 2 mm. f Impaired brain clearance in MCAO mice compared to sham mice, n = 7 for MCAO group, n = 8 for sham group, two-way ANOVA with Sidak’s multiple comparisons test, MCAO: P = 0.9822, Sham: P = 0.0046. Fluorescence signal at 6 h time point was normalized with the fluorescence signal at 0 min time point. g Brain tissue imaging for evaluating the residual NIR-II tracer of MCAO mice and Sham mice. White scale bar: 2 mm. The whole brain was manually outlined by Fiji software to measure the mean intensity. h Comparison of mean intensity of brain tissues between MCAO mice and sham mice 6 h post-infusion. The mean intensity quantifying the residual NIR-II tracer, n = 6 per group, t test, P = 0.0425. Colored dot represents the intensity of individual animal. Center is median and quartiles shown by box and whiskers. i NIR-II imaging of liver after 6 h clearance, n = 3 per group. White scale bar: 1 cm. The liver was manually outlined by Fiji software to measure the mean intensity. j-k Immunohistochemistry analysis of MCAO-induced glymphatic function impairment. Yellow represents AQP4, magenta represents vessels, and the overlap between AQP4 and vascular staining. White scale bar: 500 µm for j, White scale bar: 50 µm for k