The effect of partial zona dissection on the fertilizing capacity of chronically obstructed mouse caput epididymal sperm
Having observed that sperm from the chronically obstructed caput epididymis fertilize poorly in vitro,we investigated the effect of partial zona dissection (PZD) on fertilization in a murine model of unilateral proximal epididymal obstruction. Cleavage rates were compared for zona-intact oocytes and PZD oocytes incubated with sperm from the following epididymal segments: the obstructed caput, the contralateral nonobstructed caput, the contralateral cauda, and a sperm-free preparation to control for parthenogenesis.
Unilateral epididymal obstruction resulted in significantly higher sperm counts in the obstructed caput compared to the nonobstructed caput, although there was no difference in motility. Cleavage rates for ova incubated with sperm from the obstructed caput and the nonobstructed caput were uniformly poor and did not differ significantly from those for the sperm-free controls. Cauda sperm fertilized significantly better than all other sperm groups (P<0.05). Partial zona dissection did not improve cleavage rates in any group.
We conclude that sperm from the chronically obstructed caput epididymis, like sperm from the normal caput, are unable to fertilize ova, and PZD does not enhance this poor fertilizing capacity. Furthermore, the finding that PZD does not improve the fertilizing capacity of the presumably mature cauda sperm in our mouse model suggests that any beneficial effect of PZD may be strain-specific.
Key wordsinfertility in vitro fertilization micromanipulation spermatozoa epididymis
Unable to display preview. Download preview PDF.
- 1.Bedford JM: Effects of duct ligation on the fertilizing ability of sperm from different regions of the rabbit epididymis. J Exp Zool 1966;166:271–282Google Scholar
- 5.Temple-Smith PD, Southwick GJ, Yates CA, Trounson AO, DeKretser DM: Human pregnancy by in vitro fertilization (ivf) using sperm aspirated from the epididymis. J Vitro Fert Embryo Transfer 1985;2:119–122Google Scholar
- 10.Davis NS, Miller KF, Stowe NT, Thomas AJ: Characterization of a mouse model for chronic proximal epididymal obstruction. J Urol 1993;149(4 Suppl):477AGoogle Scholar
- 16.Stockton JD, Lipshultz LI, Findley W, Lamb DJ: Enhancement of male fertility through gamete micromanipulation. J Urol 1992;147(4 Suppl):397AGoogle Scholar