Effect of the Chinese traditional prescription Suo Quan Wan on TRPV1 expression in the bladder of rats with bladder outlet obstruction

BACKGROUND Suo Quan Wan (SQW) is a Chinese traditional prescription that has been used in clinical treatment of lower urinary tract symptoms for centuries. However, scientific basis of SQW efficacy and mechanism is still needed. This study investigated the effect of SQW on bladder function and transient receptor potential vanilloid 1 (TRPV1) expression in the bladder of rats with bladder outlet obstruction (BOO). The induced changes in bladder function in overactive bladder (OAB) rat model were observed following different periods of outlet obstruction to obtain an appropriate rat model. METHODS This study was carried out in two parts. In the first part, female Sprague-Dawley rats received sham operations or partial BOO operations. Two, four, and six weeks later, the OAB model groups and control were subjected to urodynamic tests to measure differences in bladder functions. Once the appropriate rat model was obtained, the second part of the experiment was performed. The rat model was recreated and treated with SQW. Urodynamic assessment was conducted, and the bladders of the rats were then removed. Immunofluorescence staining, real-time PCR, and Western blot were performed to localize and quantify the expression of TRPV1 in the bladder. RESULTS Results of the first part indicated that at 2 and 4 weeks, the OAB model group exhibited significant differences in urodynamic parameters, including bladder pressure, maximum voiding pressure, and maximum bladder capacity, compared with the sham group. At 4 and 6 weeks, the OAB model group exhibited significant differences in residual volume (RV) and non-voiding contraction frequency. Six-week OAB model group showed much more RV but less voiding efficiency when compared with 6-week sham group or 2-and 4-week OAB model group. Rats that underwent BOO exhibited similarities with the compensated state before four weeks and may have entered decompensated state at six weeks. Studies conducted with 4-week OAB model were appropriate. In part two of the experiment, unstable bladder in the OAB model group recovered bladder stability after SQW treatment, accompanied by improved bladder hypertrophy, as well as corrected urodynamic parameters. Expression of TRPV1 mRNA and proteins in the bladder was significantly greater in the OAB model group than that in the control group, which subsequently decreased significantly with SQW treatment in BOO-induced rats. CONCLUSIONS SQW can modulate the expression of TRPV1 in accordance with the recovery of bladder function.