Oct 15, 2025
JAX-Sen: Placenta collection, processing, and shipment protocol
- Alicia Warren1,
- Vicki Ingalls1,
- Susan Sheehan1
- 1The Jackson Laboratory, Bar Harbor, ME, USA
- Cellular Senescence Network (SenNet) Method Development Community
Protocol Citation: Alicia Warren, Vicki Ingalls, Susan Sheehan 2025. JAX-Sen: Placenta collection, processing, and shipment protocol. protocols.io https://dx.doi.org/10.17504/protocols.io.81wgbw9jygpk/v1
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: October 14, 2025
Last Modified: October 15, 2025
Protocol Integer ID: 229781
Keywords: placenta collection, mouse samples, genotyping, sex determination, limb staging, JAX-Sen, shipment of mouse placenta sample, mouse placenta sample, placenta sample, mouse placenta, shipment protocol this protocol, shipment protocol, protocol, jax, shipment, procedures for the collection, processing, procedure
Funders Acknowledgements:
National Institute on Aging (NIA) JAX-Sen Senescence Tissue Mapping Center
Grant ID: U54 AG079753
Abstract
This protocol outlines the procedures for the collection, processing, and shipment of mouse placenta samples.
Troubleshooting
Safety warnings
Follow all institutional guidelines for animal handling and euthanasia. Use personal protective equipment (PPE) when handling reagents and samples.
Reagents and Materials:
Reagents
Buffer MAC's buffer - Used for preserving placenta samples
Fixative 10% Neutral Buffered Formalin (NBF) - Used for tissue fixation
Buffer RNAlater - Preserves RNA in samples
Buffer PBS
Materials
Dissecting scissors (Sharp, stainless steel)
Petri dishes
Vials (5 mL and scintillation vials)
Ice (For wet ice preparation)
Cold packs (For sample shipping)
Procedure:
Collection:
Euthanize mice via cervical dislocation.
a. Record start time
Open the female's abdomen carefully as to not damage any fetuses.
a. Euthanize fetuses via decapitation if they are older than E15
Remove the hind left limb from one animal per litter.
Keep in 1x PBS until ready to take a image for limb staging
Separate individual yolk sac containing fetus and embryos
Remove any un-needed tissue (such as yolk sac and uterine wall) from placenta. There will be a layer of tissue on the side on the placenta connecting to the umbilical cord that will need to be removed. Similar looking layer of tissue on the other side is part of the placenta and should not be removed.
a. Step 6 to 9 can either be done in order of embryo or all steps for all embryos at once
Take appropriate measurements in mm
a. Diameter of the placenta
b. Crown to rump length (CRL) of embryo
Process Placenta
| A | B | C | D | |
| MAC's buffer | place placenta in 5 mL vial filled with the buffer | Ensure that the placenta is completely submerged | Place tube in wet ice | |
| 10% NBF | place placenta is scintillation vial filled with FFPE (10% NBF) | Ensure that the placenta is completely submerged | ||
| RNA later | place placenta in 5 mL vial filled with the buffer | Ensure that the placenta is completely submerged | Place tube in wet ice |
Take piece of the embryo (ideally tail) for genotyping and another piece as back-up. Place on wet ice.
Record time when the last sample was collected
Clean tools and proceed to next animal
Limb Staging:
Cut the left hind limb from the embryo
Put the limb in a Petri dish with PBS (palm side down)
Take an image of the limb and save it as a JPEG.
Upload the image and use 'pan and zoom mode' so that the limb fills the whole box
Trace the limb as accurate as possible
Press 'Stage Embryo' and record the result.
Sample Storage:
| A | B | C | |
| MACs Buffer | Keep at 4C (wet ice) | Ship same day on cold packs | |
| RNALater | Keep at 4C (wet ice) | Ship same day on cold packs. | |
| FFPE | Keep at 4C (wet ice) | Transfer to a shaker at room temperature to fix for 24 hours. Then transfer and submit samples while keeping them at 4C and RNase free | |
| Embedded Placentas | Keep at 4C/RNase free | until ready for shipping |
Sample Shipping:
Ship via same day shipping to the Robson Lab on cold packs to keep the samples at 4C.