How do you store stained (fluorescent antibody) tissue slides after mounting?

Slide storage is becoming a problem in my lab. Typically, we use fixed frozen tissues (DRG/SC) and then do a standard IHC protocol and use fluorescent secondary antibodies. I then use Prolong Gold (Invitrogen) to mount. I usually take images within a few hours to a day. But for long term storage, there are mixed opinions about storing at -20C or at 4C in the dark. What do you do?

@tberta Do you have any thoughts? it’d be easier to store in a cold room in racks than in the -20C space, which is limited.

Hey Alex,

I’ve always done -20C and found that they stay pretty well when I have pulled them out a few weeks/months later. I don’t know how well 4C in the dark works. How long do you want to preserve them for? I’ve heard some of groups storing samples even in -80 for very long term storing (also probably depends on the type of tissue you are referring to)

I have recently done some IHC and we typically keep our stained slides at 4C in black slide boxes. I looked at my slides from 4 weeks ago today and have not found any difference to how they looked when I first stained them.
I use Fluoromount G to mount my slides with a coverslip on top. I think it depends on how well your slides are sealed.

Thanks @fmoehring and @LegakisL. I usually stored at -20C and stuff looks good. But recently I also stored at 4C for well over a month, and the staining (IHC and ISH) actually looked great. Which is why I brought up the question. For tissue slices that haven’t been stained, we do -20C and I know some people do -80C. But once mounted, I think I may go 4C.

I imagine there are cases where -20C or -80C would be superior. Perhaps for a labile antigen or fluorscent protein. GFP would benefit I think from the cold. Already native GFP signal is somewhat weak. But with antibody staining, I think 4C would be adequate.

We do store unstained slides at -80C and wrap tape around the slide box so that they are sealed until we are ready to stain them.

FYI. I’ve been looking at some slides stored 4C for 2-3 months and they’re still looking good! Both IHC and ISH.