after fixation of slide with 4% formalin, how to stain them to see anti-protease proteins. i.e. Antibody of respective enzyme and secondary anti-body labelled with FITC?
Attached is the protocol you are looking for. Specific answer to your query is
"Livers were fixed in freshly prepared 4% paraformaldehyde (BDH Chemicals Ltd., Poole, UK) in PBS, pH 7.4, for 1 h in room temperature, then washed three times in PBS followed by cryoprotection in 20% sucrose in PBS overnight at 4degC. Pieces of the organs were mounted in OCT Tissuetek (Miles Laboratories Inc., Elkhart, IN), then snap-frozen in cold. The livers were cut in 3um sections on a cryostat. The sections were kept floating in PBS 1 0.05% sodium-azide (Sigma Chemical Co., St. Louis, MO) at 4degC until analyze"
I have copied this section from the attached paper.