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Title:
Experimental studies on afferent bladder C-fiber in pathogenesis of overactive bladder
Author:
Subject:
lidocaine ; cyclophosphamid ; afferent C-fibres ; overactive bladder ; capsaicin
Abstract:
Cyclophosphamide (CYP) treatment induces chemical cystitis leading to bladder overactivity (OAB). Different types of unmyelinated afferent C-fibres, such as capsaicin-sensitive and capsaicin-resistant mediate the voiding reflex in OAB. This study investigates the urodynamic effect of primary afferent neuronal modulation on detrusor activity and the severity of neurogenic inflammatory response in normal and overactive bladder model rats. Experiments were performed on 66 female rats. OAB was induced by CYP. All the surgical procedures and urodynamic studies (UDS) were performed under urethane anaesthesia. We analyzed basic and additional urodynamic parameters. After UDS we performed histological examination. The severity of inflammation was examined according to mucosal abrasion, hemorrhage, leukocyte infiltration and edema. Additionally we estimated the activity of mastocytes. Our results show that acute and chronic CYP administration lead to extent neurogenic inflammation and activity of inflammatory cells then subsequently to OAB development. In healthy rats capsaicin causes complete inhibition of detrusor contractility resulting in improper voiding function, whereas lidocaine has no influence on micturition cycles in intact animals. Capsaicin and lidocaine reduces the severity of detrusor overactivity of OAB rats causing improvement of cystometric parameters. This observation ; supports the hypothesis, that in the pathophysiology of OAB two types of C-fibres: capsaicin-sensitive and capsaicin-resistant play an imperative role.