@article{oai:soar-ir.repo.nii.ac.jp:00013411,
 author = {Abdalla,  H and Hirabayashi,  A and Hochi,  S},
 issue = {3},
 journal = {THERIOGENOLOGY},
 month = {Feb},
 note = {The objective was to investigate the ability of freeze-dried (FD) bull spermatozoa to induce calcium oscillations in mouse oocytes and meiosis resumption in in vitro-matured bovine oocytes after intracytoplasmic sperm injection (ICSI). Bull spermatozoa were freeze-dried and stored for 1 y at +25, +4, or -196 degrees C. In the first experiment, rehydrated sperm heads were microinseminated into hybrid mouse oocytes loaded with fluo-3/AM, and the kinetics of intracellular calcium concentration was monitored for I h. Repetitive increases of intracellular calcium concentration were recorded in the majority of injected oocytes, with exception of a few oocytes injected with FD sperm heads stored at +4 degrees C (11%) and +25 degrees C (8%) that exhibited a single increase or no response (non-oscillated). The proportion of oocytes that oscillated with high frequency (>= 10 spikes/h) was higher in the non-dried control group (79%; P < 0.05) than in the FD groups (58, 55, and 54% for storage at -196, +4, and +25 degrees C, respectively). In the second experiment, control and FD spermatozoa were microinseminated into in vitro-matured, denuded bovine oocytes. The oocytes were fixed and stained 12 h after ICSI. A higher proportion of bovine oocytes injected with control spermatozoa (70%; P < 0.05) resumed meiosis than those injected with +25, +4 and -196 degrees C stored FD spermatozoa (53, 48, and 57%, respectively). The proportion of ICSI oocytes that developed to the pronuclear stage (complete activation) was higher in the control group (64%; P < 0.05) than those in all the FD groups (34, 27, and 28% for storage at -196, +4, and +25 degrees C, respectively). Thus, the ability of bull spermatozoa to induce frequent intracellular calcium spikes in mouse oocytes was impaired by the process of freeze-drying, without differences among storage at +25, +4 or -196 degrees C, probably resulting in a lower proportion of bovine oocytes that resumed meiosis and/or developed to the pronuclear stage., Article, THERIOGENOLOGY. 71(3):543-552 (2009)},
 pages = {543--552},
 title = {The ability of freeze-dried bull spermatozoa to induce calcium oscillations and resumption of meiosis},
 volume = {71},
 year = {2009}
}