title: Procedure for bovine ICSI, not sperm freeze-drying, impairs the function of the microtubule-organizing center.
abstract: This study was designed to investigate whether freeze-dried (FD) bull spermatozoa maintained the function of the microtubule-organizing center (MTOC) after rehydration and intracytoplasmic sperm injection (ICSI). In a preliminary attempt, the cleavage and blastocyst formation rates in FD-ICSI zygotes (36 and 1%, respectively) were found to be considerably lower than those in control ICSI zygotes (67 and 21%, respectively) or in IVF zygotes (78 and 43%, respectively). An alkaline comet assay indicated that the DNA fragmentation index (length of comet tail % DNA liberated) was not significantly different between fresh and FD spermatozoa. In the main experiment, formation of sperm-asters in the FD-ICSI oocytes 7 h postinsemination occurred at a similar rate when compared with the control ICSI oocytes (41 vs. 49%). Among the oocytes exhibiting sperm aster formation, the extent of microtubule network assembly was comparable between the FD-ICSI and control ICSI groups. However, the MTOC of the ICSI oocytes was not as functional as that of IVF oocytes in terms of the aster formation rate (97%) and the fluorescent intensity of the microtubule network (2.0 folds). These results suggest that the freeze-drying process per se had no adverse effect on maintaining the MTOC function in bull spermatozoa.
authors.affiliation: Graduate School of Science and Technology, Shinshu University, Nagano, Japan.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Hara
authors.forename: Hany
authors.initials: H
authors.lastname: Abdalla
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Morita
authors.forename: Masashige
authors.initials: M
authors.lastname: Kuwayama
authors.forename: Masumi
authors.initials: M
authors.lastname: Hirabayashi
authors.forename: Shinichi
authors.initials: S
authors.lastname: Hochi
mesh_terms: D000818:Animals; D001755:Blastocyst; D002417:Cattle; D053938:DNA Fragmentation; D047108:Embryonic Development; D005612:Freeze Drying; D008297:Male; D022101:Microtubule-Organizing Center / Q000502:physiology*; D012662:Semen Preservation / Q000379:methods*; D020554:Sperm Injections, Intracytoplasmic / Q000009:adverse effects*; D013094:Spermatozoa / Q000502:physiology*