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Differential development of rabbit embryos following microinsemination with sperm and spermatids
Author(s) -
Ogonuki Narumi,
Inoue Kimiko,
Miki Hiromi,
Mochida Keiji,
Hatori Masanori,
Okada Hironori,
Takeiri Shuji,
Shimozawa Nobuhiro,
Nagashima Hiroshi,
Sankai Tadashi,
Ogura Atsuo
Publication year - 2005
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.20363
Subject(s) - biology , spermatid , blastocyst , andrology , embryo , germ cell , oocyte , sperm , human fertilization , embryogenesis , spermatogenesis , inner cell mass , microbiology and biotechnology , anatomy , genetics , endocrinology , medicine , gene
Abstract Microinsemination is the technique of delivering male germ cells directly into oocytes. The efficiency of fertilization after microinsemination and subsequent embryo development may vary with the animal species and male germ cells used. The present study was undertaken to observe the in vitro and in vivo developmental ability of rabbit embryos following microinsemination with male germ cells at different stages. First, we assessed their oocyte‐activating capacity by injecting them into mouse and rabbit oocytes. The majority of mouse oocytes were activated irrespective of the type of rabbit male germ cell injected (61–77%), whereas rabbit oocytes were activated differently according to the type of male germ cells (89%, 75%, and 29% were activated by spermatozoa, elongated spermatids, and round spermatids, respectively; P < 0.05). After 120 hr in culture, 66%, 45%, and 13%, respectively, of these activated rabbit oocytes (pronuclear eggs) developed into blastocysts ( P < 0.05). Additional electric pulse stimulation of round spermatid‐injected oocytes increased the blastocyst rate to 43%. After 24 hr in culture, some four to eight cell embryos were transferred into the oviducts of pseudopregnant females. Normal pups were born from spermatozoa and elongated spermatids, but not from round spermatids. Karyotypic analysis at the morula/blastocyst stage revealed that the majority of round spermatid‐derived embryos had abnormal ploidy (8 out of 12 embryos). Our study indicates that rabbit male germ cells acquire the ability to activate oocytes and to support subsequent embryo development as they undergo spermiogenesis. As these differential developmental patterns are similar to those reported for humans in vitro and in vivo, rabbits may provide an alternative small animal model for studying the biological nature and molecular basis of human microinsemination techniques, especially those using immature male germ cells. Mol. Reprod. Dev. © 2005 Wiley‐Liss, Inc.