The change of COX-2 expression in rats with stress urinary incontinence and its significance / 医学研究生学报

ABSTRACT

Objective　There are a few researches on the mechanism of stress urinary incontinence (SUI). The article aimed to examine the changes of COX-2 expression in the urethra, vagina and urethral smooth muscle of SUI rat mode to evaluate the effect of estrogen on COX-2 expression. Methods　Sixty unbearing healthy female SD rats and fifteen male SD rats were gathered for spontaneous delivery. SUI rat models were constructed using expanded vagina, expanded vagina + ovariectomy respectively after delivery, which were expanded vagina group and expanded vagina + ovariectomy group. Six successfully modeled rats were chosen for the follow-up experiment. SD rats modeled after normal pregnancy were the control group. Sneezing experiment and urodynamic examination were used to examine the maximum bladder capacity (MBC) and abdominal leak point pressure (ALPP). Fluorescent quantitative PCR and western blot were applied to detect the expressions of COX-2 mRNA and protein, and immunohistochemistry was used to detect the expressions of COX-2 in urethra, vagina and urethral smooth muscle. Results Compared with control group, ALPP in two experimental groups were significantly decreased, among which ALPP in expanded vagina + ovariectomy group was significantly decreased in comparison to expanded vagina group(P<0.05). Compared with control group, the expressions of COX-2 mRNA and protein in expanded vagina group and expanded vagina+ovariectomy group were significantly higher, among which the figures in expanded vagina+ovariectomy group were significantly higher than those in expanded vagina group(P<0.05). The result of immunohistochemistry showed staining intensity integral expression of COX-2 in vaginal tissues of control group, expanded vagina group and expanded vagina+ovariectomy group were 0.50±0.54, 5.55±0.54, 9.33±0.81, so differences between any two groups were of statistical significance(P<0.05); staining intensity integral expression of COX-2 in urethral smooth muscle of control group, expanded vagina group and expanded vagina+ovariectomy group were 0.66±0.51, 5.33±0.51, 8.50±0.54, so differences between any two groups were of statistical significance (P<0.05). Conclusion The expression of COX-2 was related to the mechanism of SUI. The decrease of estrogen may increase the expression of COX-2 in SUI rats, which supports the treatment of SUI.