From what I've read up on, HOT works effectively to repair a damaged bladder lining. They offer this to people who have chemical cystitis and I know of one who has done this. It involves rounds of daily sessions in the hyperbaric chamber - so maybe 6 days a week for 7 weeks.
Ozone is supposed to work in a similar way, but more direct if it goes inside the bladder. I once posted up a NZ study done on rabbits. It's in the Research section.
Again, I think it works to 'repair' a damaged bladder lining. But possibly doesn't deal with the cause of the damage in things like IC/PBS.