Tibial nerve stimulation diminishes mast cell infiltration in the bladder wall induced by interstitial cystitis urine.

Objectives: To investigate whether the urine of interstitial cystitis (IC) patients has a toxic effect on the bladder wall, as determined by mast cell infiltration, and to evaluate the preventive effect of tibial nerve electric stimulation (TNES) on bladder mastocytosis induced by IC urine.

Material And Methods: The bladders of female rats were catheterized and instilled with IC urine (Group IC; n=10) and normal urine (Group NU; n=5) obtained from humans, saline (Group S; n=5) and protamine sulphate (Group PS; n=10) for 6 weeks. Additionally, in five rats instilled with IC urine and five instilled with PS, TNES was also performed (Groups IC + TNES and PS + TNES).

Results: In the lamina propria of the bladder, the mean number of mast cells per square millimetre was significantly higher in Groups IC (32.5+/-12.3) and PS (39.4+/-11.1) than in Groups S (11.9+/-4.3) and NU (13.7+/-3.5). After TNES, the corresponding values were decreased significantly to 15.3+/-5.4 and 15.3+/-4.1 in Groups IC + TNES and PS + TNES, respectively (p<0.001). A significant reduction in mast cell infiltration in the detrusor was also determined after TNES compared with the value in Group IC (4.6+/-1.6 vs 12.1+/-3.0; p<0.001).

Conclusions: We demonstrated that IC urine may result in increased mast cell infiltration in the bladder wall. TNES may play a therapeutic role by diminishing the mast cell count in the bladder wall, which has a strong relationship with nociceptive neural endings.