Stuck strut rod

I can't seem to get the nut off the front of the strut rod on the passenger side of my Duster. I've tried penetrating fluid, heat, hitting with a hammer etc and nothing seems to work. I put two nuts on the other side of the strut rod to hold it tight and tried getting the nut off the front and it just turns the strut and beings to muck up the threads on the other side of the rod so that method isn't going to work. Do you guys know of another method? I don't know if using vise grips to try and hold it still will mess up the rod but I'm not sure if that method would work anyway since the nut is stuck on so tight.