Nov 02, 2023

Public workspaceFree-floating Mouse Brain Immunohistochemistry V.2

  • 1University of Cambridge
Open access
Protocol CitationJonathan Breiter 2023. Free-floating Mouse Brain Immunohistochemistry. protocols.io https://dx.doi.org/10.17504/protocols.io.261ged3j7v47/v2Version created by Jonathan Breiter
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License,  which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: November 02, 2023
Last Modified: November 02, 2023
Protocol Integer ID: 90330
Keywords: ASAPCRN
Abstract
This protocol enables immunohistochemical staining of murine tissue with superior penetration of the tissue by the reagents due to the free-floating approach.

In this new version, the last step contains a supplemental video with extra context and tips, as part of the ASAP Protocol Particulars, featuring conversations with protocol authors
Materials
10x PBS pH 7.4, Gibco, Cat. No: 70011-036
Triton X-100, Merck, Cat. No: 648466-50ML
Bovine Serum Albumin heat shock fraction, Sigma-Aldrich, Cat. No: A9647 - 100G
Normal Goat Serum, Fisher Scientific, Cat. No: 11819220
Vectashield Antifade Mounting Medium PLUS, Vector Labs, Cat. No: H-1900
Mouse mAb to Alpha-synuclein pS129 (81A), Abcam, Cat. No: ab184674, RRID:AB_2819037
Donkey anti-Mouse IgG (H+L) Alexa Fluor 568, Thermo Fisher, Cat. No: A10037, RRID: AB_2534013
Millex Filter Unit 0.22 um, Merck, Cat. No: SLGP033RS
12 Well Cell Culture Plate, Corning, Cat. No: 3513
24 Well Cell Culture Plate, Thermo Scientific, Cat. No: 144530
Netwell Permeable Supports 15mm Diameter Insert 74 um Polyester Mesh, Costar, Cat. No: 3477
Micro Slides Single Frosted 75 x 25 mm, Corning, Cat. No: 2948-75X25
Cover Glass 22 x 50 mm Thickness No. 1, VWR, Cat. No: 631-0137

Tissue Preparation
Tissue Preparation
Remove PFA-fixed tissue from storage solution and add to mesh bottom netwell insert inside of 12 well plate that is filled with 0.22 μm filtered 1x PBS.

Place the 12 well plate with the tissue on a horizontal shaker and wash tissue 3x 5 min at approx. 150 rpm, moving the netwell insert to the next well down after each 5 min period to immerse the tissue in new 1x PBS. TemperatureRoom temperature

Buffer Preparation
Buffer Preparation
Per well of tissue make a minimum of 3.5 mL of blocking solution, consider this is needed for blocking, primary and secondary antibody incubation. All reagents should be 0.22 μm filtered:

1x PBS
5% Normal Goat Serum
2.5% Bovine Serum Albumin
0.2% Triton-X

Make in excess and keep on ice. Keep at 4 degrees celcius overnight. Temperature4 °C

Primary Antibody Incubation
Primary Antibody Incubation
In a new 12 well plate, add 2-3 mL per well of blocking solution and transfer the washed tissue sections inside their netwell inserts into these wells. Incubate for 1h - 2.5 h on horizontal shaker at approx 150 rpm. TemperatureRoom temperature

Meanwhile, dilute primary antibodies in blocking solution to appropriate concentrations and keep TemperatureOn ice .

E.g.
- Mouse monoclonal anti pS129 (81A) (ab184674) @ 1:750
Add approx 250 ul of primary antibody solution to the approriate number of wells of a 24 well plate for the number of brain sections.
When blocking is finished, move brain tissue sections from the netwell inserts to their appropriate primary antibody well using a fine paintbrush, being careful not to destroy the tisssue.
Incubate on horizontal shaker at approx. 150 rpm overnight. Temperature4 °C

Secondary Antibody Incubation
Secondary Antibody Incubation
Prepare a new 12 well plate with clean netwell inserts and fill all wells with 0.22 μm filtered 1x PBS.
Transfer brain tissue sections from 24 well plate into netwell inserts inside 12 well plate and wash 4x 10 minutes on a horizontal shaker at approx. 150 rpm. TemperatureRoom temperature

Meanwhile, make appropriate dilutions of secondary antibody in blocking solution. Keep away from light and keep TemperatureOn ice .

E.g.
- Donkey anti-Mouse Alexa Fluor 568 (A10037) @ 1:500
Add approx 250 ul of secondary antibody solution to the approriate number of wells of a 24 well plate for the number of brain sections.
When washing step is finished, move brain tissue sections from the netwell inserts to their appropriate secondary antibody well using a fine paintbrush, being careful not to destroy the tisssue.

Keep the well plates covered from now to avoid bleaching of fluorophores.
Incubate 24 well plate on a horizontal shaker at room temperature at approx. 150 rpm for 1 h - 2.5 h. TemperatureRoom temperature

Transfer brain tissue sections from 24 well plate into netwell inserts inside 12 well plate and wash 4x 10 minutes on a horizontal shaker at room temperature at approx. 150 rpm. TemperatureRoom temperature

Microscope slide preparation & Imaging
Microscope slide preparation & Imaging
Plasma-clean microscope cover slips in Argon plasma for 15 minutes.
Using a fine paintbrush, transfer brain tissue sections from 1x PBS onto a microscope slide, using excess 1x PBS to mount multiple sections next to each other and making sure they are not folded over.
Leave sections on microscope slides to dry out in the dark (they will turn white).
Add approx. 150 uL of mounting media on top of each tissue section and apply the plasma-cleaned cover slip on top of the tissue, closing the slide.
Leave the mounting media to dry in the dark.
Seal the edges of the coverslip with nail varnish and let dry for approx. 30 minutes in the dark.
Immediately take finished microscope slides to imaging, avoiding unecessary light exposure.
ASAP Protocol Particulars: context and tips
ASAP Protocol Particulars: context and tips