Histology TUNEL Staining

• Deparafinize sections.
• Block endogenous peroxidase with 6% H2O2 in methanol for 5 min. at room temp.
• Rinse with PBS for 1 min.
• Block avidin and biotin (15 min. each followed by 3x5 min. washes with PBS).
• Incubate slides in Proteinase K solution (1 mL Proteinase K in 50 mL deionized water) for 15 min. at room temp.
• Rinse with water 2x2 min.
• Incubate slides in 1X TdT labeling buffer (dilute the 10 stock with deionized water) for 5 min. at room temp.
• Cover section (bout 50 m l) with Labeling Reaction Mix (1 mL B-dNTP+1 mL TdT enzyme+50 mL 1X TdT labeling buffer from step 6) for 1 hour at 37 degrees C in humidity chamber (if necessary, use cover slips).
• Immerse slides in 1X TdT Stop buffer (dilute the 10 stock with deionized water) for 5 min. at room temp.
• Rinse 2x5 min PBS.
• Incubate slides with diluted anti-BrdU (1 mL Antibody + 50 mL streptavidin diluent) for 1 hour at room temp.
• Rinse slides 3x2 min PBS containing 0.05% Tween20.
• Incubate with straptavidin-HRP solution (50 mL streptavidin diluent + 1 mL Streptavidin-HRP) for 10 min. at room temp. 
• Rinse slides 3x2 min. PBS containing 0.05% Tween20.
• Incubate sections with DAB substrate fro 10 min. at 37 degrees C.
• Rinse in water.
• Counterstain for 15 sec. in Mayer's hematoxylin.
• Rinse with water.
• Mount in water-based medium.