IMMUNOCYTOCHEMICAL IDENTIFICATION OF PROLIFERATING CELLS IN VASCULAR TISSUE (ANTI-BrdU); Vector Red Detection

1. Sections of paraformaldehyde fixed, OCT-embedded vascular tissue are sectioned at 7 to 10 mm and stored, desiccated at -70°C until needed.
2. Thaw slides immediately before use, usually 10-30 min. prior to beginning the protocol.
3. Fix in acetone 5 min., air dry for approximately 20 min., RT.
4. Immerse in Proteinase K/ 1xPBS for 10 min., RT (7.5µl Proteinase K of 20 mg/ml stock in 150ml 1x PBS for a final concentration of 1µg/ml).
5. Rehydrate in 1x PBS twice for 5 min. each, RT.
6. Immerse in 4N HCl for 10 min., RT.
7. Immerse in 1x TBE, pH 8.4 for 5 min., RT. Check pH of buffer with pH paper to see if it is neutral.
8. Immerse in 1x PBS. Check pH of buffer after 2 min. Apply primary antibody when pH is 7.0-7.5.
9. Prepare the working dilution of the primary antibody in 1.0% crystalline-grade Bovine Serum Album (BSA) in 1x PBS. Use BrdU antibody (Dako Catalog No. M744) at 1:20 dilution. Blot off PBS and apply 150µl of working dilution. Incubate sections in a humid chamber for 1 hour, RT. Blot off antibody, wash 2 times 5 min. each in 1x PBS.
10. Prepare the working dilution of the secondary antibody (Horse anti-mouse IgG-Vector Catalog No. BA2001) in 1.0% BSA/PBS, 2.0% normal horse serum. Prepare the secondary antibody at a 1/400 dilution. Apply 150µl and incubate 30 min., RT in a humid chamber. Blot off the antibody, wash 2 times 5 min. each in 1x PBS.
11. Prepare the working dilution of ABC-Vector Red complex from the Vector ABC kit (Catalog No. AK-5000) before finishing the previous step. Mix 5ml PBS, two drops of Solution A, and two drops of Solution B, and allow to sit at 4°C for 30 min. prior to use. Apply enough to cover the sections on the slide, and incubate for 1 hour. Blot off the solution, wash 2 times 5 min. each in 1x PBS, followed by 1 wash in 100mM Tris pH 8.2 for 5 min.
12. Make up Vector Red substrate solution (Catalog No. SK-5100) immediately before use. Incubate in the dark for 20-30 min, stop color reaction by blotting off substrate and rinsing in dH2O for 5-10 min.
13. Counterstain with hematoxylin, 1% acid-alcohol, Scott's solution, dehydrate through graded alcohols, then xylenes per protocol below, and coverslip for viewing.

Solutions:

Proteinase K

Dissolve Proteinase K (Sigma Catalog No. P-4914) in dH2O for a concentration of 20mg/ml.

1% BSA/PBS

1g Fraction V BSA in 100ml 1x PBS. Mix in a beaker with low heat. Aliquot in 15ml tubes and store at -20°C.

Hematoxylin

75ml Gill's hematoxylin no.2 in 75ml dH2O.

1% Acid-alcohol

2ml HCl in 198ml of 70% ethanol.

Scott's Solution

NaHCO3, 2g

MgSO4.7H2O, 20g

dH2O, 1000ml