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
The Immunohistochemistry (IHC) Staining for Mouse Brain Sections protocol details the blocking, primary, and secondary antibody staining of 50-100 micron mouse brain tissue slices fixed in 4% PFA. The protocol includes suggested staining duration based on slice thickness for each staining step and tables of the most frequently requested blocking serums and primary and secondary antibody stains and dilutions.
Recipes - blocking and DAPI solutions should be made depending on experimental need
1L 1xPBS:
Combine the following reagents into a container with a stir bar. A graduated cylinder may be used to measure MilliQ water and a graduated cylinder or serological pipet may be used to measure 10xPBS. Mix well on a stir plate at high speed (300 RPM or higher) for 00:02:00 or until solution is mixed. Store at Room temperature for 1 month.
Reagent
Volume
Milli-Q water
900 mL
10xPBS
100 mL
1L 1xPBS & Sodium Azide 0.01% :
Combine the following reagents into a container with a stir bar, using a graduated cylinder to measure the 1xPBS and a P5000 pipette to measure the 5% sodium azide. Mix well on a stir plate at high speed (300 RPM or higher) for 00:02:00 or until solution is mixed. Store at Room temperature or 4 °C for up to 1 year.
Reagent
Volume
1xPBS
998 mL
0.01% Sodium Azide
2 mL
1L 1xPBS & Triton X-100 0.2%:
Measure 1xPBS into a container with a stir bar using a graduated cylinder and slowly pipet Triton X-100 in using a P5000 pipette. Mix well on a stir plate at high speed (300 RPM or higher) for 00:15:00 to ensure Triton X-100 goes into solution. Store at Room temperature for 1 month.
Reagent
Volume
1xPBS
998 mL
Triton X-100
2 mL
1L 1xPBS & Triton X-100 0.06%:
Measure 1xPBS into a container with a stir bar using a graduated cylinder and slowly pipet Triton X-100 in using a P5000 pipette. Mix well on a stir plate at high speed (300 RPM or higher) for 00:15:00 to ensure Triton X-100 goes into solution. Store at Room temperature for 1 month.
Reagent
Volume
1xPBS
994 mL
Triton X-100
6 mL
2mL 5mg/mL DAPI solution:
Add Milli-Q water to DAPI powder in 10mg vial using P5000 pipette. Vortex until powder completely mixes into solution. Store at 4 °C and vortex before use.
Reagent
Volume
Milli-Q water
2 mL
DAPI powder
10 mg
200 mL 5% Normal Goat Serum & Triton X-100 0.06% & 4M Urea (NGSTU)
Measure urea on scale and add into a container for mixing NGSTU. Add 10x PBS into the container with a serological pipet, then add normal goat serum, Triton and water to container using manual pipette. Add stir bar to container and mix on stir plate at high speed (300 RPM or higher) for 00:15:00 to ensure all reagents fully homogenize. This working solution can be stored at 4 °C and used for up to 1 week. Beyond this time, there would be concern for possible microbial contamination that would affect performance.
*Amount of blocking serum made should be determined by number of sections to be stained.
Reagent
Amount
Normal Goat Serum
10 mL
Urea
48 g
10X PBS
20 mL
Triton X-100
120 uL
Milli-Q Water
Fill to 200 mL
200 mL 5% Normal Donkey Serum & Triton X-100 0.2% in PBS (NDST)
Measure 10X PBS into container with a serological pipet, then add Normal Donkey Serum, Triton, and water to container using manual pipette. Add stir bar to container and mix on stir plate at high speed (300 RPM or higher) for 00:15:00 to ensure all reagents fully homogenize. This working solution can be stored at 4 °C and used for up to 1 week. Beyond this time, there would be concern for possible microbial contamination that would affect performance.
*Amount of blocking serum made should be determined by number of sections to be stained.
Reagent
Amount
Normal Donkey Serum
10 mL
10X PBS
20 mL
Triton X-100
400 uL
Milli-Q Water
Fill to 200 mL
200 mL 5% Normal Goat Serum & Triton X-100 0.06% (NGST):
Measure 10X PBS into container with a serological pipet, then add normal goat serum, Triton, and water to container using manual pipette. Add stir bar to container and mix on stir plate at high speed (300 RPM or higher) for 00:15:00 to ensure all reagents fully homogenize. This working solution can be stored at 4 °C and used for up to 1 week. Beyond this time, there would be concern for possible microbial contamination that would affect performance.
*Amount of blocking serum made should be determined by number of sections to be stained.
Reagent
Amount
Normal Goat Serum
10 mL
10X PBS
20 mL
Triton X-100
400 uL
Milli-Q Water
Fill to 200 mL
Safety warnings
DAPI is a mutagen and should be handled with care. Wear PPE and dispose into hazardous waste stream. Please consult your immediate supervisor or the EH&S manager/representative if you have questions or concerns.
Sodium Azide is toxic and carcinogenic. It should be handled and prepared with care. Do not breathe dust, do not use metal utensils. Wear gloves when handling this chemical.
Paraformaldehyde is carcinogenic. Wear gloves at all times when handling specimen tissue slices fixed in paraformaldehyde, as the tissue may contain trace amounts of the chemical.
Personal Protective Equipment (PPE) should be used at all times while operating this protocol. If you are unsure what PPE you should be using, see your immediate supervisor.
Before start
This protocol details staining of mouse brain tissue that has already been sectioned. Reference the following protocol for instructions on sectioning a whole mouse brain fixed in 4% PFA: Sectioning Mouse Brain with Sliding Microtome
For all steps, protect tissue from light in order to preserve fluorescence by wrapping well plate in foil between steps and during washes and stains.
Setup
Setup
Well plate setup:
Select either a plastic well plate or Netwell cell culture inserts for tissue section staining.
Note
A plastic well plate may be helpful for conducting multiple different stains simultaneously, while a Netwell kit may be efficient for applying the same stain to a large number of tissue sections.
Fill wells with 1xPBS and place tissue sections to be stained into wells.
If there are a large amount of tissue sections, the sections may be double or triple stacked in each well in the well plate (or more if using Netwell insert), but ideally sections in the same well should be separated by at least a few hundred microns (ex: every 6th section or more) so it is easier to see anatomical differences and determine section order when mounting.
If tissues will be stained in different conditions (ex: staining sections with different primary or secondary antibodies) it is best to draw a map of these conditions on the plastic well plate lid and a corresponding map in lab notebook.
Staining
Staining
3d 0h 10m
3d 0h 10m
Wash mouse brain sections three times in 1xPBS for 00:05:00 at Room temperature on shaker using either a plastic well plate or Netwell kit with mesh inserts.
Note
In this step and all subsequent steps, protect tissue from light to prevent bleaching by wrapping well plate in foil while it is on the shaker.
15m
Blocking:
Select blocking solution. See examples of frequently requested blocking solutions below:
Choose a blocking duration based on section thickness. See table below. Note that suggested blocking durations are minimums and sections may be blocked up to Overnight
Section thickness
Blocking duration
50 microns
1 hour
100 microns
2 hours
Wash sections in chosen blocking solution for chosen blocking duration on shaker at Room temperature
Primary staining:
Choose a primary antibody and dilution based on tissue labeling. See table below for commonly requested primary antibodies and dilutions. If using NDST, NGST, or NGSTU as blocking serum, dilute the primary antibody in tube with blocking serum. If using Block Aid as blocking serum, dilute the primary antibody in tube with 1xPBS & Triton X-100 0.2%. Mix primary antibody dilution mixture in tube by gently swirling.
Chose a staining duration based on section thickness. Note that the durations below are minimums and sections may be stained up to 72:00:00
Section thickness
Primary antibody staining duration minimums
50 microns
24+ hours
100 microns
48+ hours
3d
Remove blocking solution and incubate tissue in chosen primary antibody solution on shaker at 4 °C or Room temperature for chosen staining duration.
Note
If no secondary antibody stain is required, skip to step 7.
Wash sections in new wells containing 1xPBS & Triton X-100 0.2% five or more times for 00:05:00 on shaker at Room temperature
25m
Secondary staining:
Choose a secondary antibody and dilution based on the primary antibody used. See table below for commonly requested secondary antibodies and dilutions. If using NDST, NGST, or NGSTU as blocking serum, dilute the secondary antibody in tube with blocking serum. If using Block Aid as blocking serum, dilute the secondary antibody in tube with 1xPBS & Triton X-100 0.2%. Mix secondary antibody dilution mixture in tube by gently swirling.
Frequently requested secondary antibodies
Suggested dilution
DAPI (5 mg/mL stock concentration, then diluted to working concentration) combine with secondary antibody
Jackson Immuno goat anti-chicken 488 (703-545-155)
1:500
Invitrogen goat anti-rabbit 594 (A-11012)
1:500
Invitrogen donkey anti-goat 647 (A-21447)
1:500
Note
If additional DAPI stain is required in combination with secondary antibody, continue with step 6.2. If not, skip to step 6.3.
Vortex 5 mg/mL DAPI solution and dilute it to preferred concentration in secondary antibody solution. 1:5000 is a common dilution for DAPI.
Safety information
DAPI is a mutagen, so wear PPE (gloves, lab coat, safety goggles) and dispose in hazardous waste stream.
Choose a staining duration based on section thickness. Suggestion below are minimums and secondary staining duration may run up to 48:00:00 :
Section thickness
Secondary staining duration minimuns
50 microns
1+ hour
100 microns
2+ hours
2d
Incubate sections in chosen secondary antibody solution for chosen staining duration on shaker at Room temperature
Wash sections in 1xPBS & Triton X-100 0.2% three times for 00:05:00 on shaker at Room temperature
25m
Wash sections in 1xPBS two times for 00:30:00 on shaker at Room temperature
30m
Store samples in 1xPBS for short term use or 1xPBS & Azide 0.01% for long term use (Overnight or up to several weeks) at 4 °C until ready for mounting.
Safety information
Sodium Azide is toxic and carcinogenic. It should be handled and prepared with care. Do not breathe dust, do not use metal utensils. Wear gloves when handling this chemical.