Changes in the contractile activity of the male genital tract as a consequence of vasectomy

Abstract

The contractile activity of the cauda epididymidis and vas deferens was registered in the rat under a video camera at intervals up to 180 days after vasectomy. A rhythmic peristaltic activity was detected as early as 24 hours after operation, specially in the distal cauda epididymidis. The contractions increased progressively during the first 30 days after vasectomies. Thereafter, the activity remained stabilized as far as 180 days following the surgery. The contractions were more frequent in the genital tracts without granulomas than in those with this complication. When the ductus exhibited an excessive distention their muscle walls did not show any contractility, which was not recovered even when a partial incision was made in the vas deferens to diminish the tube dilatation. Since a normal pattern of sperm transport would be necessary to achieve sperm maturation, it could be speculated that persistence of infertility after vasovasostomies in human could be related with a loss of an adequate ductal activity.

PIP: By means of a video recording system, the contractile muscle activity in the cauda peididymidis and vas deferens of male Wistar rats after vasectomy was studied over time. A rhythmic peristaltic activity was detected in the genital tracts of vasectomized rats as early as 24 hours after the procedure, with a mean frequency of 9.5 contractions/10 minutes. This activity increased progressively in the 1st 30 days after vasectomy and then stabilized as long as 180 days. By 30 days after surgery, all genital tracts exhibited sperm extravasation. The proximal ligated end of the vas deferens was the most common site for granuloma. The contractions were more frequent in genital tracts without granulomas than in those with this complication. When the ductus exhibited excessive distention, there was no contractility in the muscle walls, even when a partial incision was made in the vas deferens to reduce tubal dilatation. This suggests that extreme distention can damage the contractibility of the muscle fibers. Since the advance and return of sperm inside the tubes could facilitate the interaction of sperm with secretions participating in its maturation, the persistent infertility after vasectomy could be related to the contractile alteration that follows the excessive tubal distention. The partial reduction of the high intravasal pressure occurring during sperm extravasation relieves extreme distention of the ductal muscle, suggesting that granuloma formation may prevent damage to the contractile components and reduce the effectiveness of vasectomy.