Source: Hasegawa, S., et al. Whole-Kidney Three-Dimensional Staining with CUBIC. J. Vis. Exp. (2022).
This video demonstrates an assay for the whole-mount staining of murine kidneys using a tissue-clearing method called CUBIC (clear, unobstructed brain/body imaging cocktails and computational analysis) and immunofluorescent staining. The kidney is subjected to tissue clearing, wherein the kidney is delipidated, decolorized, and treated with a refractive index matching solution to make the tissue transparent for optimum three-dimensional imaging. The tissue is stained with fluorescently labeled antibodies to reveal sympathetic nerves and arteries in the tissue under a light-sheet microscope.
All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
1. Animal preparation and kidney fixation
2. Decolorization and delipidation
3. Whole-mount immunofluorescent staining
4. Refractive index (RI) matching
5. Image acquisition and reconstruction
Figure 1: Tissue clearing and whole-mount immunofluorescent staining. Tissue clearing by CUBIC is a two-step process: delipidation (CUBIC-L) and refractive index (RI) matching (CUBIC-R+). Whole-mount staining is performed after the delipidation process. Scale bar = 10 mm. The image is reproduced from Hasegawa et al.
Figure 2: Images of the handling process. (A) The sample is immersed in 7 mL of 50% or 100% CUBIC-L in a 14 mL round bottom tube. The tube is kept horizontal with gentle shaking during the delipidation process. (B) A dispensing spoon is used for sample handling. (C) The amount of the staining buffer needed for one kidney is 500-600 µL. The tube is kept vertical during the staining process. (D) Although the sample floats in 50% CUBIC-R+ at the beginning of the RI matching, it sinks and becomes transparent in CUBIC-R+ at the end of the process.
Figure 3: Light sheet fluorescent microscopy for whole-kidney 3D imaging. Light sheet fluorescent microscopy (LSFM) enables three-dimensional (3D) imaging of transparent samples. This image is reproduced from Hasegawa et al.9. Immersion oil is used during data acquisition. Light sheets from both sides illuminate the sample. The excitation signals are acquired through the objective lens located in a vertical position. The stage moves in the axial direction, and z-stack images are obtained. Scale bar = 10 mm.
The authors have nothing to disclose.
14 mL Round Bottom High Clarity PP Test Tube | Falcon | 352059 | Tissue clearing, staining, wash |
2,3-dimethyl-1-phenyl-5-pyrazolone/antipyrine | Tokyo Chemical Industry | D1876 | CUBIC-R+ |
37%-Formaldehyde Solution | Nacalai Tesque | 16223-55 | Post fixation |
4%-Paraformaldehyde Phosphate Buffer Solution | Nacalai Tesque | 09154-85 | Kidney fixation |
Alexa Flour 555-conjugated donkey anti-sheep IgG antibody | Invitrogen | A-21436 | Secondary antibody (1:100) |
Alexa Flour 647-conjugated donkey anti-rabbit IgG antibody | Invitrogen | A-31573 | Secondary antibody (1:200) |
Anti-aquaporin 2 (AQP2) antibody | Abcam | ab199975 | Primary antibody (1:100) |
Anti-podocin antibody | Sigma-Aldrich | P0372 | Primary antibody (1:100) |
Anti-sodium glucose cotransporter 2 (SGLT2) antibody | Abcam | ab85626 | Primary antibody (1:100) |
Anti-tyrosine hydroxylase (TH) antibody | Abcam | ab113 | Primary antibody (1:100) |
Anti-α-smooth muscle actin (α-SMA) antibody | Abcam | ab5694 | Primary antibody (1:200) |
Blocker Casein in PBS | Thermo Fisher Scientific | 37528 | Staining buffer |
Butorphanol Tartrate | Meiji | 5526 | Anesthetic |
C57BL/6NJcl | Nippon Bio-Supp.Center | N/A | Mouse strain |
Imaris | Bitplane | N/A | Imaging analysis software |
Macro-zoom microscope | OLYMPUS | MVX10 | The observation unit of the custom-built microscope |
Medetomidine Hydrochloride | Kyoritsu-Seiyaku | 8656 | Anesthetic |
Midazolam | SANDOZ | 27803229 | Anesthetic |
Mineral oil | Sigma-Aldrich | M8410 | Immersion oil |
N-buthyldiethanolamine | Tokyo Chemical Industry | B0725 | CUBIC-L, CUBIC-R+ |
Nicotinamide | Tokyo Chemical Industry | N0078 | CUBIC-R+ |
Polyethylene glycol mono-p-isooctylphenyl ether/Triton X-100 | Nacalai Tesque | 12967-45 | CUBIC-L, PBST |
Silicon oil HIVAC-F4 | Shin-Etsu Chemical | 50449832 | Immersion oil |
Sodium azide | Wako | 195-11092 | Staining buffer |