The influence of castration on intramural neurons of the urinary bladder trigone in male pigs

Abstract

The present study investigated the influence of castration performed at neonatal age on neuronal elements in the intramural ganglia of the urinary bladder trigone (UBT) in male pigs using double‐labeling immunohistochemistry. The ganglia were examined in intact (IP) 7‐day‐old (castration day) pigs, and at 3 and 6 months after surgery. In IP and control (3‐ and 6‐month‐old noncastrated pigs) groups, virtually, all neurons were adrenergic (68%) or cholinergic (32%) in nature. Many of them (32%, 51%, and 81%, respectively; 56%, 75%, and 85% adrenergic; and 32%, 52%, and 65% cholinergic, respectively) stained for the androgen receptor (AR), and only a small number of nerve cells were caspase‐3 (CASP‐3)‐positive. In 3‐ and 6‐month‐old castrated pigs, an excessive loss (87.6% and 87.5%, respectively) of neurons and intraganglionic nerve fibers was observed. The majority of the surviving adrenergic (61% and 72%, respectively) and many cholinergic (41% and 31%, respectively) neurons expressed CASP‐3 and were also AR‐positive (61% and 66%, and 40% and 36%, respectively). This study revealed for the first time the excessive loss of intramural UBT neurons following castration, which could have resulted from apoptosis induced by androgen deprivation.

The Effect of Castration on Peripheral Autonomic Neurons Supplying Mammalian Male Genitourinary System

“…In both cases, they are "mixed" autonomic ganglia consisting of either sympathetic adrenergic or parasympathetic cholinergic neurons. Recent investigations of Kaleczyc et al [12] and earlier findings [61], which have revealed that the vast majority of UBT intramural neurons in male pigs are either adrenergic or cholinergic in nature, seem to further confirm this concept. No wonder then that changes in percentages of adrenergic and cholinergic neurons observed after castration [12] were similar to those found in the APG.…”

“…Recent investigations of Kaleczyc et al [12] and earlier findings [61], which have revealed that the vast majority of UBT intramural neurons in male pigs are either adrenergic or cholinergic in nature, seem to further confirm this concept. No wonder then that changes in percentages of adrenergic and cholinergic neurons observed after castration [12] were similar to those found in the APG. In the 3-and 6-month-old castrated male pigs, the percentages of adrenergic and cholinergic neurons were comparable (41% and 39%, and 58% and 58%, respectively) but they differed significantly from those determined in the non-castrated animals of the same age (68% and 68%, and 31% and 31%, respectively).…”

“…As stated earlier, information concerning gonadal steroid actions on peripheral neurons derives almost entirely from previous investigations performed in the male rat major pelvic ganglion (MPG) and, to a lesser extent, the hypogastric ganglion (HG) [ 8 ], and recent studies carried out on the male pig APG and intramural ganglia of the UBT [ 10 , 11 , 12 ].…”

“…In contrast to the male rat, in the male pig, castration at age 1 week results in the excessive loss of APG and UB intramural neurons in at least the trigone area [ 11 , 12 ]. The experiment involved 25 male pigs.…”

“…Recently, a few contributions in the field have been published [ 10 , 11 , 12 ], which provide some new and interesting findings. First, these studies were performed in male pigs; second, they considered elements of both above-mentioned approaches combining the surgical removal of testes (castration) with immunohistochemical and/or quantitative real-time PCR (qPCR) investigations of AR expression in neurons of the anterior pelvic ganglion (APG) and intramural ganglia of the urinary bladder (UB) trigone (UBT); third, the comparison of the corresponding findings obtained in male rats and pigs reveals substantial differences, which may be of great importance for planning further investigations aimed at obtaining results important for human and veterinary medicine.…”