Effects of Connexin Expression on Unstable Bladder after Relief of Bladder Outlet Obstruction in Rat

Kim, Joon Chul; Kim, Doo Bae; Seo, Seong Il; Park, Yong Hyun; Hwang, Tae Kon

Abstract

PURPOSE: Connexins (Cx) constitute a family of transmembrane proteins that form gap junction channels, and allow metabolic and electrical coupling of cellular networks. This study was undertaken to evaluate the regulation of Cx expression, according to bladder function, after the relief of a bladder outlet obstruction in rat.
MATERIALS AND METHODS
50 Wistar male rats were used for this study. They were divided into two groups: 10 in a control group, and 40 in an experimental group. The experimental group was partially obstructed for 3 weeks, after which the obstruction was relieved by urethral deligation. 3 weeks after the deligation, cystometrograms (CMG) were performed. On the basis of the CMG results, the experimental group was subdivided into the normalized and unstable groups. The bladders from each group were dissected after the CMG, and weighed. The expressions of Cx43 and Cx40 mRNA in each group were analyzed by a reverse transcriptase polymerase chain reaction (RT-PCR).
RESULTS
The bladder weights of both the normalized and unstable groups increased compared with the control group (p<0.05). On CMG, the contraction interval of the unstable group was markedly decreased compared with that of the control and normalized groups (p<0.05). The semiquantitative RT-PCR revealed that there was no significant difference in the expressions of Cx43 mRNA between the control and normalized groups. However, the expression of Cx43 mRNA of the unstable group was significantly increased compared with the control and normalized groups. The expression of Cx40 mRNA was no different between the groups.
CONCLUSIONS
Our results show that there is a change in the expressions of the onnexins according to bladder function, which may be related to a persistent unstable bladder or irritative symptoms following the relief of a bladder outlet obstruction.