Trypan blue as an indicator of urothelial integrity

Defects in the urinary bladder urothelium may be an etiological factor in conditions such as recurrent urinary tract infection and interstitial cystitis. Initial studies have demonstrated that the colloidal dye trypan blue can be used as a marker for defects in the integrity of the mucosal epithelium. Male white New Zealand rabbits were separated into 4 groups: Control, in vivo overdistension (via saline infusion), intravesical acetone (20 ml 50% for 1 minute), and intravesical 50% DMSO (20 ml “RIMSO‐50” for 30 minutes). Both intravesical instillations were followed by 3–20 ml saline washes. Immediately following acetone or DMSO, 20 ml 1% trypan blue in saline was instilled and left in the bladder for up to 1 hour. After overdistension, 1% trypan blue in saline was infused into the bladder at the same rate until the volume reached that previously defined as the overdistension volume. Control bladders were rinsed with 20 ml saline, twice, before being filled with 20 ml of the trypan blue solution.