The Change of Mast Cell and Smooth Muscle Contractility of Trachea, Intestine and Urinary Bladder in Sensitized Rats

Abstract

Purpose: We used the sensitized rat model to study the effect of the inflammation evoked by immune response on the smooth muscles of the urinary bladder, trachea and intestine and changes of mast cell.Materials and Methods: The rats were divided into 3 groups (group 1: control - not-sensitized. no antigen challenge, group 2: sensitized, no antigen challenge, group 3: sensitized, antigen challenge). Each group was divided into two subgroups of male and female. Rats were sensitized by intraperitoneal injection of ovalbumin (10mg/ml/kg) given on days 1, 3 and 5, 4 weeks after last injection, sensitized rats were treated with intravesical ovalbumin for 1 hour (antigen challenge) and controls runned simultaneously with the unsensitized rats by intravesical instillation of normal saline. After intravesical instillation contractility and number of mast cells of each organ were measured.Results: Only female-sensitized group showed significantly increased contractility of bladder muscle (p＜0.05) while no significant difference in trachea and intestine among groups. In male rats there were no significant differences between groups and organs. In male and female groups, there was increased contractility in female rats than male but showed no significant difference between sexes. In histologic study, sensitized, ovalbumin group showed more mast cells in detrusor muscle and submucosa than non-sensitized, saline group in both male and female rats. Also there were significant differences in female rats than male rats. Detrusor to submucosa mast cell ratio was significantly higher in sensitized, ovalbumin group.Conclusions: We concluded that there might be some other factors that made differences in response to antigen challenge between sexes and among the organs. We observed increased contractility in female rat bladder and this may explain higher incidence of interstitial cystitis in female than male.