OBJECTIVE: This study was designed to evaluate the effect of testosterone replacement on the fibrotic process of the detrusor bladder muscle during the normal aging process. METHODS: 15 Wistar senile rats, aged between 18 and 20 months were divided into two groups: testosterone group - 11 animals submitted to the administration of testosterone undecanoate (50 mg/kg intramuscular), once per month; and, Control group - four animals underwent a sham procedure. At the end of eight weeks, animals from both groups were sacrificed; bladders were removed and subsequently stereologically evaluated to determine the volumetric density of collagen fibers. The success of testosterone administration was confirmed by the measurement of serum testosterone at the beginning and end of the experiment. RESULTS: In the replacement group, testosterone average was 3.2 ng/ml, whereas in the control group, the mean testosterone at the end of the experiment was 0.64 ng/ml (p < 0.05). Analysis of stereological collagenous fiber showed higher density in the control group compared to the testosterone group I (56% versus 37.02%, respectively). The difference of volume concentration of collagen between both groups was statistically significant (p < 0.000). CONCLUSION: Bladder wall fibrosis was reduced in senile rats subjected to testosterone replacement.
OBJECTIVE: This study was designed to evaluate the effect of testosterone replacement on the fibrotic process of the detrusor bladder muscle during the normal aging process. METHODS: 15 Wistar senile rats, aged between 18 and 20 months were divided into two groups: testosterone group - 11 animals submitted to the administration of testosterone undecanoate (50 mg/kg intramuscular), once per month; and, Control group - four animals underwent a sham procedure. At the end of eight weeks, animals from both groups were sacrificed; bladders were removed and subsequently stereologically evaluated to determine the volumetric density of collagen fibers. The success of testosterone administration was confirmed by the measurement of serum testosterone at the beginning and end of the experiment. RESULTS: In the replacement group, testosterone average was 3.2 ng/ml, whereas in the control group, the mean testosterone at the end of the experiment was 0.64 ng/ml (p < 0.05). Analysis of stereological collagenous fiber showed higher density in the control group compared to the testosterone group I (56% versus 37.02%, respectively). The difference of volume concentration of collagen between both groups was statistically significant (p < 0.000). CONCLUSION: Bladder wall fibrosis was reduced in senile rats subjected to testosterone replacement.