

Proceed to downstream cell separation, fluorescence activated cell sorting (FACS) or flow cytometry analysis (view our recommended surface and intracellular flow cytometry staining protocols) or other applications.Resuspend the cell pellet in 1X PBS and proceed to cell count on the cellometer.Add 3X the volume of 1X PBS to the microglia cells to dilute the percoll and centrifuge for 5 minutes at 365 x g at room temperature.Do NOT discard! Transfer these cells to a separate 15 mL conical tube. This layer contains microglia and leukocytes. Using another transfer pipette, remove the interphase between 70% and 37% percoll.With a transfer pipette, remove the interphase between 1X PBS and 30% Percoll.Centrifuge gradient for 40 minutes at 300 x g at room temperature WITHOUT brakes.Note: If processing more than 1 brain, do NOT scale up! Use multiple 15 mL polypropylene conical tubes to process 1 brain each. The final solution should contain (from top to bottom): 2 mL 1X PBS, 4 mL of 30% percoll, 4 mL of cells in 37% percoll, 4 mL of 70% percoll. Slowly add 4 mL of 70% percoll, 4 mL of 30% percoll, followed by 2 mL of 1X PBS.Transfer the 4 mL of cells in 37% SIP (from step 12) into a 15 mL polypropylene conical tube.37% percoll: 3.7 mL SIP + 5.3 mL 1X PBS.Stock Isotonic Percoll (SIP): Mix 1 part 10X PBS and 9 parts percoll.Prepare several percoll gradient solutions (warmed to room temperature):

Optional steps: Myelin Removal for Microglia, Leukocyte Isolation If you do not wish to remove myelin, resuspend in PBS and leave on ice. Otherwise, proceed to downstream cell separation, fluorescence activated cell sorting (FACS), flow cytometry analysis (view our recommended surface and intracellular flow cytometry staining protocols), or other applications of choice.

Filter the suspension through a 70 μm filter several times (3-4X) and manually gently homogenize the remainder of the clumps.To triturate, you may pipet up and down using either 12 or 50 mL serological pipettes, or glass pipettes. After 10 – 15 minutes, triturate the brain clumps until mostly dissociated and add 20-30 mL of complete RPMI.Note: Do NOT leave in trypsin for more than 15 minutes. Every 5 minutes gently shake and invert the tube or gentle pipette the tissue by using 10 mL or 50 mL pipette. Add 10 mL of trypsin to the tube containing the brain, and incubate at 37☌ in an incubator or water bath.Transfer the segments of the brain into a 50 mL polypropylene conical tube.Gently separate the brain into 6-8 pieces.below for additional information on this procedure. Note: Due to the effect of trypsin digestion on certain surface antigen epitopes, you may use a dounce homogenizer in lieu of trypsinization in step 7.

