Abstract: 【Abstract】 Objectives To investigate the role of estrogen and the mast cells in the pathogenesis of the interstitial cystitis patients,specifically with respect to activated bladder mast cells. Methods 18 cystoscopy biopsy specimens from patients with interstitial cystitis and 12 control subjects were analyzed blindly for the numbers of mast cells and the presence of estrogen receptors(ER). Immunohistochemical methods were used to detect ER and MC．And double immunohistochemical staining was used to manifest the expression of ER in interstitial cystitis MC． Results Bladder MC alone were shown to express high affinity ER，ER+cells in IC (3.77±3.03/HP) comparing with controls（0.88±0.76/HP）(t=3.870,P<0.01) and there was a higher number of MC present in patients with IC（5.59±3.40/HP）compared with controls（2.48±2.23/HP） (t=2.787,P<0.01).The unique finding that only MC express ER(R=0.884，P<0. 01),in spite of the inflammatory infiltrate present. Conclusions MC high affinity estrogen receptors may help to explain why interstitial cystitis occurs primarily in women,why IC and other associated symptoms tend to be worst at the midcycle. These results have shown that estrogen augment MC histamine secretion, which have a high prevalence in women such as IC.

Key words: Interstitial Cystitis, Mast Cell, Estrogen Receptor