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

Objective: To investigate the relationship of transforming growth factor beta1 (TGFbeta1) and basic fibroblast growth factor (bFGF) to detrusor underactivity following bladder outlet obstruction (BOO).

Methods: 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.

Results: 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].

Conclusion: 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.