| Abstract: | We reported previously that substances in interstitial cystitis urine, when infused into the rabbit bladder, induce changes that resemble bladders of interstitial cystitis (IC) patients. Here we report our investigation of the effect of additional molecular weight subfractions of IC urine and lower infusion volume in this rabbit bladder bioassay. Urine was pooled from symptomatic IC patients, asymptomatic IC patients (in remission), and normal volunteers. Two fractions of 20× concentrated urine were obtained for each of the 3 groups: a 10–100-kD fraction and a fraction > 100 kD but <0.22 μm. Six rabbits per group were infused twice per week with 6 ml of 1 of these 6 urine fractions or saline as a control. After 6 weeks, each rabbit was cystoscoped before and after hydrodistension, bladder capacity and urea permeability were determined, and the bladder was removed for histologic examination. A questionnaire revealed a significant difference (P < 0.01) regarding voiding symptom severity between symptomatic IC patients and both normal volunteers and IC patients in remission. There was no statistically significant difference among groups of rabbits in cystoscopic bladder appearance, bladder capacity, urea permeability, or bladder histology. If a urine-borne factor is in part responsible for IC symptoms, the rabbit bladder must be filled with urine to near capacity to be able to detect a difference between IC and normal urine in this rabbit bladder bioassay. Neurourol. Urodynam. 17:147–152, 1998. © 1998 Wiley-Liss, Inc. |
