To begin, remove the tissue from the bones of the euthanized dissected mouse. Place the cleaned bones into a new six-well plate containing FACS buffer placed on ice. Transfer the bones into a mortar with two to five milliliters of FACS buffer.
Grind the bones in a circular motion until the bone marrow is released. With a three milliliter syringe, pull up and flush down the bone marrow to homogenize it. Pull the homogenate into another syringe, then filter it through a 70 micrometer cell strainer into a 50 milliliter tube.
Rinse the tissue chunks from their filter back into the mortar with FACS buffer before homogenizing a second time. Filter the rinsed tissue as before. Next, rinse the remaining bone spicules back into the mortar with FACS buffer.
Then flush the pieces into a 15 milliliter tube to ensure maximum yield. To digest the bone marrow, first centrifuge it at 300 G for five minutes at four degrees Celsius. Resuspend the bone marrow pellet in two milliliters of digestion mixture.
Transfer the mixture to a 15 milliliter tube. Then incubate it at 37 degrees Celsius for 45 minutes on a rotator. Now, add 10 milliliters of FACS buffer to stop the enzymatic digestion.
Filter the mixture through a 70 micrometer cell strainer into a 50 milliliter tube. Centrifuge the suspension at 400 G for seven minutes at four degrees Celsius. Resuspend the pellet in one milliliter of RBC lysis buffer.
Next, add 10 milliliters of FACS buffer to halt the lysis. Then filter the mixture as before into a 50 milliliter tube. Lastly, centrifuge the mixture at 300 G for five minutes at four degrees celsius.
After discarding the supernatant, resuspend the pellet in 100 microliters of FACS buffer. For the digestion of bone spicules, first, vortex the bone spicules. Decant the supernatant and retain the bones at the bottom.
Next, resuspend the spicules in one milliliter of the bone spicule digestion mixture. Incubate the tube on a rotator for 60 minutes at 37 degrees Celsius. Finally, stop the digestion with 10 milliliters of FACS buffer.
Filter the mixture into the 50 milliliter tube containing RBC lysed and digested bone marrow.