Without boring everyone by quoting a lot of studies, let's just say that the process of having UCPPS does seem to make some permanent changes to the organs in the pelvis. While these changes are very small, they do seem to lead to increased reactivity to any noxious stimuli.
The actual physical changes are probably an increase in mast cells in places like the epithelium (lining) of the bladder and/or urethra and/or prostate. These mast cells are created by the overactivity of the nerve endings in these structures, because of cross-talk with perpetually activated nerves elsewhere (to put it very simply). We know that bladders of IC patients contain a higher number of mast cells than control patients (study, study etc). These mast cells make the linings of the organs and structures more reactive to irritants in the urine, for instance, or more reactive to further stimulus from the nerves.
I'm not sure I'm explaining this well, and I caution you all that I am a couple of steps ahead of fully accepted UCPPS theory here. But I am putting 2 and 2 together for you here, based on known science. I welcome comments, questions, corrections and refutations.There were significantly more nerve fibres within the sub-urothelium and detrusor muscle in chronic IC than there were in non-ulcerative IC. The bladder washings from all patients with IC contained mast cells and histamine, while only occasional mast cells and traces of histamine were found in washings from patients with non-ulcerative IC. There was a good correlation between the number of nerve fibres and number of mast cells as well as between the number of nerve fibres and the amount of histamine. (source)
