title: Effect of pH value of freeze-drying solution on the chromosome integrity and developmental ability of mouse spermatozoa.
abstract: The nuclei of freeze-dried mouse spermatozoa are able to retain their chromosome integrity and developmental potential. To optimize the conditions of freeze-drying, we examined whether pH values of the freeze-drying solution affect the chromosome integrity and developmental potential of sperm nuclei. The sperm freeze-drying solution we used contained a high concentration (50 mM) of calcium-chelating EGTA. Sperm chromosomes were examined at the metaphase of the first mitosis after injection of freeze-dried spermatozoa into matured oocytes. The developmental potential of sperm nuclei was assessed by examining the development of fetuses in midgestation. The results showed that both sperm chromosomes and sperm developmental potential are maintained better when the freeze-drying solution was slightly alkaline (pH 8.0) rather than near neutral or acidic (pH 7.4-6.0). The data indicated that the chromosome integrity and developmental ability of mouse spermatozoa are affected by the pH value of freeze-drying solution.
authors.affiliation: The Institute for Biogenesis Research, Department of Anatomy and Reproductive Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96822, USA. takehito@hawaii.edu
authors.forename: Takehito
authors.initials: T
authors.lastname: Kaneko
authors.forename: David G
authors.initials: DG
authors.lastname: Whittingham
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Yanagimachi
mesh_terms: D000818:Animals; D002614:Chelating Agents; D002875:Chromosomes; D003451:Cryoprotective Agents; D004533:Egtazic Acid; D004624:Embryo Transfer; D005314:Embryonic and Fetal Development; D005260:Female; D005612:Freeze Drying / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D011247:Pregnancy; D012662:Semen Preservation / Q000379:methods*; D012996:Solutions; D020554:Sperm Injections, Intracytoplasmic; D013091:Spermatogenesis; D014325:Tromethamine
chemical_list: D002614:Chelating Agents; D003451:Cryoprotective Agents; D012996:Solutions; D014325:Tromethamine; D004533:Egtazic Acid