Please find the following media preparation method:
PI Counterstain Solution
PI Stock Solution (1mg/ml or 1.5 mM):
To prepare, add 1 mg PI (Propidium Iodide) to 1 ml distilled water. Store stock solution at 4 C (or aliquot and store at -20 C), protecting from light. When handled properly, solutions are stable for many years.
RNase A Stock Solution (1mg/ml):
To prepare, add 1 mg RNase A to 1 ml distilled water. Aliquot and store at -20 C freezer.
PI Working Solution (1 ug/ml PI and 10 ug/ml RNase A in PBS):
To prepare, add 2 ul PI Stock Solution and 20 ul RNase A Stock Solution to 2 ml PBS
Incubate sections in dark for 30 minutes at room temperature or 20 minutes at 37 C.
Staining Pattern: Nuclei will be stained red.
Counterstain for immunofluorescence when green (FITC) or blue (AMCA) fluorescent marker is used.