Published-Ahead-of-Print January 22, 2009, DOI:10.2164/jandrol.108.006395
Journal of Andrology, Vol. 30, No. 3, May/June 2009
Copyright © American Society of Andrology
DOI: 10.2164/jandrol.108.006395
Effect of Egg Yolk on Cryopreservation of Rhesus Monkey Ejaculated and Epididymal Sperm
QIAOXIANG DONG*,
AND
CATHERINE A. VANDEVOORT*,
From the * California National Primate Research
Center, University of California, Davis, California; the
School of Environmental Science and Public
Health, Wenzhou Medical College, Wenzhou, China; and the
Department of Obstetrics and Gynecology,
School of Medicine, University of California, Davis, California.
|
Correspondence to: Dr Catherine A. VandeVoort, PhD, California National
Primate Research Center, University of California, Davis, CA 95616 (e-mail:
cavandevoort{at}ucdavis.edu). |
Sperm cryopreservation in rhesus monkeys has not been successful when
applied in standard, intravaginal artificial insemination; thus, there is a
need for substantial improvement in current cryopreservation protocols. The
present study was part of our systematic approach to optimize the
cryopreservation procedure. Specifically, we tested whether modification of
the concentration of egg yolk, the dilution method, and the time delay between
ejaculation and adding egg yolk would result in significant improvement of
postthaw motility for ejaculated sperm. We also tested the effects of presence
and absence of egg yolk on cryopreservation of ejaculated and epididymal
sperm. Our findings indicated that the concentration of egg yolk
(2%–50%, vol/vol), the dilution method, and the delay (1–5 hours)
in addition of egg yolk had no significant effect on postthaw motility of
ejaculated rhesus monkey sperm. The presence of egg yolk yielded significantly
higher motility after thawing than samples without egg yolk for ejaculated and
epididymal sperm. The present study suggests that as long as egg yolk is
present in the extender, details such as the amount of egg yolk, as well as
when and how to add the egg yolk, have little impact on the ultimate freezing
outcomes for ejaculated rhesus monkey sperm. We also discuss the possible
mechanism of the protective role of egg yolk in sperm cryopreservation.
Key words: Epididymides, assisted reproduction, semen, Macaca mulatta, nonhuman primates
Copyright © 2009 by The American Society of Andrology.