Journal of Andrology, Vol. 26, No. 2, March/April 2005
Copyright © American Society of Andrology
Effect of Vasectomy on Sperm Nuclear Chromatin Condensation in the Rabbit
KLAUS STEGER*,
MILEN SLAVOV*,
,
KLAUS FAILING
,
WOLFGANG WEIDNER* AND
MARTIN BERGMANN
From the * Department of Urology and Pediatric
Urology,
Research Training Group 533,
Cell-Cell-Interaction in Reproductive Medicine, German Research Foundation;
Institute of Veterinary Physiology, Department
of Biomathematics;
Institute of Veterinary
Anatomy, Histology and Embryology, Giessen, Germany.
|
Correspondence to: Dr Klaus Steger, Department of Urology and Pediatric
Urology, Rudolf-Buchheim-Strasse 7, D-35385 Giessen, Germany. (e-mail:
Klaus.Steger{at}chiru.med.uni-giessen.de). |
Histone-to-protamine exchange in haploid spermatids is known to play a
central role for male fertility. The present study investigates, for the first
time, the effects of vasectomy on the expression of protamines in the rabbit.
During normal spermatogenesis, protamine-1 and protamine-2 mRNA were expressed
from step 5 round spermatids to step 11 elongated spermatids. In unilaterally
vasectomized animals, control testes revealed normal spermatogenesis with
normal protamine expression, while vasectomized testes exhibited both normal
spermatogenesis and spermatogenic arrest. Some testes with normal
spermatogenesis revealed delayed expression of both protamine-1 and
protamine-2. Furthermore, multinucleated round spermatids were a regular
finding in these testes. In both treated and untreated animals, a higher
percentage of spermatozoa from the cauda epididymis had highly condensed
chromatin when compared with those from the testis. The percentage of
spermatozoa with highly condensed chromatin from testes and epididymides from
the vasectomized side of treated animals remained unchanged from controls. As
the integrity of nuclear chromatin is important for oocyte fertilization,
especially in intracytoplasmic sperm injection (ICSI), where most of the
natural selection mechanisms are bypassed, our data add valuable information
for the treatment of infertility by ICSI, showing that vasectomy may affect
nuclear chromatin integrity of testicular spermatids but not epididymal
spermatozoa. Microsurgical epididymal sperm aspiration (MESA), therefore, may
be superior to testicular sperm extraction (TESE) in vasectomized
patients.
Key words: Protamine, spermatogenesis, vasectomy
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Copyright © 2005 by The American Society of Andrology.