Spinal cord staining with samples isolated from formalin-fixed carcasses

I am working on immunostaining of spinal cord samples that are isolated from carcasses that have been fixed in formalin for a long period of time( about 4-6 month). The staining did not work pretty well( the signal was low with lots of background). I was wondering whether you have any recommendation on that.

That level of fixation is going to make IHC hard. You will need to look into antigen retrieval. I never have to do that b/c i do very short fixation. Good luck. @sshiers - Any thoughts?

I agree, antigen retrieval is necessary. I’d do a strong antigen retrieval treatment, like pepsin.

Take some sections and put them into 0.15mg/mL pepsin in 0.2N HCl at 37C for 5, 10, 20 minutes, etc. Wash after, and then proceed with blocking and antibody staining. See what looks best.