Most RNA preservation solutions are concentrated salt solutions that protect RNA by precipitating it inside the cell. The wash buffers etc. used in immunofluorescence are variations on physiologic saline, so the RNA preservation solution will get washed out during the immunos and will no longer protect the RNA. So you definitely won't be able to do immunos and RNA extraction on the same sample.

As to whether immunos would work at all, I'm really not sure. I think it depends entirely on whether your epitope survives the high salt condition and returns to its normal configuration once the salt is washed out. I would incubate the samples in PBS at 4C with gentle shaking to remove the RNA Save - I don't know how long that would take, you might need to try a few conditions. If your immunos typically require fixation, you will also need to do that, and I think you would probably want to wash out the salt first, and THEN fix the tissue. I also don't know what kind of effect being salted and then rehydrated will have on morphology. Hopefully it works, I'd be interested to hear how it went if you decide to try it!

Thx,

I don't think I will try it on these samples, I will try to collect new samples.