IHC in Cartilage
Posted 29 June 2010 - 05:27 PM
I am attempting (unsuccessfully, as you may have guessed) to perform anti-caspase IHC on paraffin-embedded mouse cartilage. I am studying apoptosis in fracture calluses, and have previously gotten real-looking positive results using TUNEL, but have been unable to successfully perform IHC to confirm my results. I either have a maddening excess of background or no stain at all, and after tweaking pretty much all of the steps, I am at a loss as to what I should do.
Here are the conditions in which the tissues are prepared:
-Fixation in 4% PFA overnight
-Decalcification in 19% EDTA for 4 weeks at 4C then embedded in paraffin blocks
-Sectioned at 10um thickness
-I'm using 2 different polyclonal rabbit anti-caspase antibodies, the goat anti-rabbit secondary kit from vector (catalog number pk-6101), and the DAB kit from vector.
I have tried various dilutions of both the primary (1:25 up to 1:500) and secondary, various DAB incubation times, antigen retrieval with Proteinase K (37C for 15min), antigen retrieval with citrate buffer, blocking, no blocking, jumping 5 times on my left foot and spinning clockwise 3 times, praying to the IHC gods, and talking to my sections pleadingly, but nothing has worked.
Posted 30 June 2010 - 02:27 AM
Posted 06 July 2010 - 02:36 PM
That's one of the most frustrating things! When I run the same protocol at the same time on skin, I get a high background in the skin when I get no stain at all in the fracture callus.