Pronuclear formation of freeze-dried canine spermatozoa microinjected into mouse oocytes.
OBJECTIVE
The aim of the present study was to investigate the fertilizing capacity of fresh, frozen-thawed and freeze-dried canine spermatozoa.


METHODS
After canine spermatozoa were injected into mouse oocytes, the rates of oocyte activation, male pronuclear formation and chromosomal aberrations were investigated.


RESULTS
The rates of oocyte activation were comparable (90.6-100%), no matter the sperm type injected. The percentage of male pronuclear formation was higher (P < 0.001) in the freeze-dried spermatozoa (92.3%) than the fresh (61.5%) and frozen-thawed (69.2%) spermatozoa. However, the chromosomal damage in the oocytes injected with freeze-dried spermatozoa was higher (72.9%: P < 0.001) than with fresh (26.9%) and frozen-thawed (21.4%) spermatozoa.


CONCLUSIONS
These data indicate using mouse oocytes that freeze-dried canine spermatozoa may potentially fertilize canine oocytes although chromosomal damage is frequently generated.
Department of Food Production Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan.
Hiroyuki
H
Watanabe
Tomoyoshi
T
Asano
Yasuyuki
Y
Abe
Yutaka
Y
Fukui
Hiroshi
H
Suzuki
D000818:Animals; D002467:Cell Nucleus / Q000502:physiology*; D015925:Cryopreservation; D004285:Dogs; D005260:Female; D005612:Freeze Drying / Q000379:methods*; D005615:Freezing; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008845:Microinjections / Q000379:methods*; D009865:Oocytes / Q000502:physiology*; D011247:Pregnancy; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods*; D013094:Spermatozoa / Q000502:physiology*