AB107. Effect of partial ureteral obstruction on the auto-rhythmicity and contractility of detrusor smooth muscle in rats

Objective: To analyze the effect of partial unilateral ureteral obstruction (PUUO) on the auto-rhythmicity and contractile function of detrusor smooth muscle in rats.

Methods: Eighty Wistar rats had been divided into four groups by random: 8-week experimental group (n=20) and sham control group (n=20), 16-week experimental group (n=20) and sham control group (n=20). Experimental animals left ureters (n=40) had been embedded the upper half into the psoas muscles. Sham control rats only received laparotomy. After the establishment of models, the rats were separated in different experimental time point to carry out the experiment strip of the ureter muscle in vitro, the contraction extent and frequency of the muscle strip were determined.

Results: The ureteral contractility and contractile frequency in 8-week experimental group were 0.62±0.38 g and (9.3±3.4) 30 s, and in the shamcontrol group were 0.25±0.59 g and (7.4±2.5) 30 s. There was a significant increase in the 8-week experimental group compared with sham control group (P<0.05). The ureteral contractility, and contractile frequency of 16-week experimental group were 0.15±0.10 g and (6.4±1.7) 60 s, while sham control group were 0.41±0.38 g and (8.2±1.7) 30 s. There was a significant decrease in the 16-week experimental group compared with sham control group (P<0.05).

Conclusions: The auto-rhythmicity and contractility of smooth muscle in PUUO rats were increased at eight weeks, while decreased at sixteen weeks. The reason that the auto-rhythmicity and contractility of smooth muscle in 8-week model rats increased may be due to compensation.

Keywords: Ureteral obstruction; auto-rhythmicity; detrusor; contractile function