Relationship of transforming growth factor beta1 and basic fibroblast growth factor to detrusor underactivity following bladder outlet obstruction: experiment with rats

Abstract

To investigate the relationship of transforming growth factor beta1 (TGFbeta1) and basic fibroblast growth factor (bFGF) to detrusor underactivity following bladder outlet obstruction (BOO). Female Wistar rats underwent ligation of the urethra to establish BOO models and were divided into BOO model 2-week group (11 rats) and BOO model 6-week group (10 rats). 8 rats underwent sham operation as control group. The detrusor urine was taken out and stimulated by carbachol to measure the detrusor contraction force (DCF). RT-PCR method was employed to measure the mRNA expression of TGFbeta1 and bFGF in the detrusor urine. Urine TGFbeta1 and bFGF were determined by ELISA. The maximum DCF levels of the BOO 2-week group under the 1 x 10(-4) mmol/L and 1 x 10(-3) mmol/L carbachol concentrations were 0.96 g +/- 0.11 g and 1.98 g +/- 0.21 g respectively, both significantly higher than those of the sham operation group (0.85 g +/- 0.18 g and 1.82 g +/- 0.19 g respectively, both P < 0.05). The maximum DCF levels of the BOO 6-week group under the 1 x 10(-5), 1 x 10(-4), 1 x 10(-3) and 1 x 10 (-2) mmol/L carbachol concentrations were 0.19 g +/- 0.02 g, 0.65 g +/- 0.06 g, 1.12 g +/- 0.08 g, and 1.40 g +/- 0.19 g respectively, all significantly lower than those of the BOO 2-week group (0.24 g +/- 0.03 g, 0.96 g +/- 0.11 g, 1.98 g +/- 0.21 g, and 2.16 g +/- 0.21 g respectively, all P < 0.05) and those of the sham operation group (0.23 g +/- 0.04 g, 0.85 g +/- 0.18 g, 1.82 g +/- 0.19 g, and 2.12 g +/- 0.26 g respectively, all P < 0.05). The mRNA expression of TGFbeta1 of the BOO 6-week group, BOO 2-week group, and sham operation group was 0.72 +/- 0.21, 0.34 +/- 0.10, and 0.32 +/- 0.01 respectively, there was a significant difference between the BOO 6-week group and the BOO 2-week group (P < 0.01). The mRNA expression level of bFGF of the BOO 6-week group was 0.38 +/- 0.13, significantly higher than those of the BOO 2-week group and sham operation group (0.21 +/- 0.07 and 0.10 +/- 0.05 respectively, both P <0.05). DCF was negatively correlated with the mNRA expression of TGFbeta1 and the mNRA expression bFGF in detrusor (both P < 0.05). The urine TGFbeta1 of the BOO 6-week group was (606 +/- 216) microg/mol Cr, significantly higher than that of the BOO 2-week group [(131 +/- 49) microg/mol Cr] and that of the sham operation group [(107 +/- 22) microg/mol Cr, both P <0.05]. With the progression of BOO, there is a sustained rise of bFGF mRNA expression in detrusor; however, the TGFbeta1 mRNA expression only increases during the decompensation stage. Urine TGFbeta1 level is very high 6 weeks after BOO, which may help predict the contraction function of bladder after BOO.