X-Ray-Based 3D Histopathology of the Kidney Using Cryogenic Contrast-Enhanced MicroCT

Figure 3

Optimization of the freezing rate for cryo-CECT and quantitative structural characterization of the glomeruli. (a) Transverse cryo-CECT slices of Hf-WD POM-stained kidneys that were frozen by submersion in isopentane at either −160°C, −78°C, or −20°C. A zoom image of the cortex (white rectangle) is shown below. Glomeruli and tubuli are indicated by the red and blue arrows, respectively. Image histograms were windowed based on their dynamic range. Hence, images are not displayed as normalized grey values in-between different datasets. (b) Typical volume rendering of the cortical kidney microstructure (Hf-WD POM and isopentane −78°C). The Bowman’s capsule of a glomerulus is rendered in green. A magnification of the Bowman’s capsule (green transparent) and the glomerulus (grey) is shown. (c) Scatter plot showing the relationship between glomerular volume and the distance-to-capsule of each glomerulus measured for all samples (S1, S2, and S3) that were frozen using isopentane −78°C. The cortex is divided in three regions (superficial, middle, and juxtamedullary) according to Zhai et al. [39]. (d) Bar graph comparing the median glomerular volume between the juxtamedullary cortex ( mm) on the one hand and superficial and middle cortex ( mm) on the other hand. (e) Bar graph comparing the median glomerular volume (15 glomeruli per kidney; either superficial or middle) between the two freezing rates. Two-sided unpaired -tests were performed. Significant values () have been indicated in the bar graphs.

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