RESUMO
Objective To investigate the role of transient receptor potential vanilloid tpye 1 (TRPV1) in the pathological process of detrusor overactivity (DO) induced by partial bladder outlet obstruction (BOO).Methods Between June 2014 and December 2014,40 female Wistar rats received partial urethral ligation and urodynamic analysis 6 weeks after.Urinary bladder and dorsal root ganglion (DRG) were removed and RT-PCR,Western Blot and IHC were performed to investigate the expression and location of TRPV1 in control and DO rats.Effect of different concentrations of TRPV1 agonist,as well as TRPV1 antagonist,was also evaluated with isolated detrusor strips.Results 40 female Wistar rats received BOO surgery and 26 of them developed DO.Immunohistochemistry observed linear TRPV1-reactive staining mainly in sub-urothelial and muscular layer.Expression of TRPV1 mRNA and protein in urinary bladder [(0.18±0.02) vs.(0.36 ±0.03),P＜0.05] and dorsal root ganglia (DRG) [(0.41 ±0.05) vs.(0.66 ±0.04),P ＜ 0.05] significantly increased in BOO induced OAB rats.In isolated detrusor strips studies,the amplitude [(0.26 ±0.05)g vs.(0.69 ±0.11)g,P ＜0.05] and frequency [(5.91 ±0.59) Hz vs.(8.75 ± 0.54) Hz,P ＜ 0.05] of contractions of DO tissues were significantly higher than that of control ones.Capsaicin significantly increased the amplitude but not frequency of detrusor intrinsic contractility and this effect was enhanced in OAB conditions.All changes induced by capsaicin were blocked by capsazepine pre-incubated.Conclusions In BOO induced DO rats,over-expressed TRPV1 was involved in DO pathological process by directly sensitizing bladder afferent fibers or indirectly enhancing detrusor intrinsic properties.
