title: Effect of pressure at primary drying of freeze-drying mouse sperm reproduction ability and preservation potential.
abstract: Freeze-dried spermatozoa are capable of participating in normal embryonic development after injection into oocytes and thus useful for the maintenance of genetic materials. We recently reported that long-term preservation of freeze-dried mouse spermatozoa by conventional methods requires temperatures lower than -80 degrees C. Successful permanent preservation of mouse spermatozoa at much higher temperatures requires thorough investigation of the freeze-drying procedure. Thus, we examined the relationship between the pressure at primary drying and the preservation potential of freeze-dried mouse spermatozoa. Three different primary drying pressures were applied to evaluate the effect of pressure on freeze-dried spermatozoa under varying storage conditions and the rate of development measured. The developmental rate of embryos to the blastocyst stage from intracytoplasmic sperm injection by freeze-dried spermatozoa at pressures of 0.04, 0.37, and 1.03 mbar without storage were 59% (337/576), 71% (132/187), and 33% (99/302) respectively. When stored at 4 degrees C for 6 months, the rate was 13% (48/367), 50% (73/145), and 36% (66/182) respectively. These results show that primary drying pressure is an influential factor in the long-term preservation of freeze-dried mouse spermatozoa.
authors.affiliation: Chugai Research Institute for Medical Science, Inc., Shizuoka, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Kawase
authors.forename: Toshio
authors.initials: T
authors.lastname: Hani
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kamada
authors.forename: Kou-ichi
authors.initials: K
authors.lastname: Jishage
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D020552:Comet Assay; D004249:DNA Damage; D004624:Embryo Transfer; D047108:Embryonic Development / Q000502:physiology; D005260:Female; D005612:Freeze Drying / Q000379:methods; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D011247:Pregnancy; D011312:Pressure; D012662:Semen Preservation / Q000379:methods*; D020554:Sperm Injections, Intracytoplasmic; D013094:Spermatozoa / Q000502:physiology*