PROPIDIUM IODIDE STAINING FOR CELL CYCLE (DNA) ANALYSIS BY FACS

PROCEDURE C 


The following procedure has been used successfully by David Killilea (Pharmacology) for cell cycle analysis of rat pulmonary artery smooth muscle cells (RPA-SMC)
 

     Grow up cell cultures and expose to appropriate experimental conditions.
     Trypsinize (0.25%, GIBCO) cells and collect in 15-ml conical tubes. At this point, many procedures call for the addition
     of buffer with serum to inactivate the trypsn; RPA-SMC apparently do not require this step.
     Centrifuge 5 min at 1,500 rpm
     Decant supernate and resuspend in 1 ml of PBS (pH 8)
     Remove 30µl from each sample and place in microfuge tubes with 30µl of 0.4% trypan blue. Mix gently.
     Count viable cells using a hemacytometer and calculate # cells/ml/
     Transfer volume of cell suspension necessary for 1-5 x 106 cells to a centrifuge tube (microfuge, if possible)
     Centrifuge 5 min at 1,500 rpm
     Decant supernate and resuspend in 150µl of 1x PBS (pH8)
     Add 375 µl of FACS buffer to each tube. Mix
     Add 250µl of RNAse to each tube.
     Add 100µl of 0.2% Triton-X 100 to each tube. Mix
     Incubate at 37C in 5% CO2 in air for 30 min
     Add 100 µl of propidium iodide solution to each tube. Cover with aluminum foil.
     Incubate at R.T. for 30 min.
     Transfer cell suspensions to Falcon 2063 tubes for FACS analysis. Samples may be stored O.N. at 4C
 
 

REAGENTS
 
FACS buffer: (250 ml: store at R.T.)  
      100 mM sodium acetate 3.4 g NaC2H3O2
       5.4 mM EDTA +0.5 g EDTA
  pH to 5.2  
  qs 250 ml  
   
RNAse: (for 1 ml; prepare fresh)  
      700 U/ml RNAse 10 mg of 70 U/mg RNAse
  +1 ml FACS buffer
   
0.2% Triton-X 100: (for 50 ml) 1 ml undiluted Trition-X 100
  +49 ml FACS buffer
   
propodium iodide solution: (for 2ml) 1 mg propodium iodide
  + 2 ml FACS buffer
   

[ Adapted from R.L. Vendor, et. al., Reduced oxygen tension induces pulmonary endothelium to release a pulmonary smooth muscle cell mitogen(s), Amer. Rev. Resp. Dis., 135:622-7, 1987.]