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Factors affecting fertilization of porcine oocytes following intracytoplasmic injection of sperm
Author(s) -
Lee JangWon,
Yang Xiangzhong
Publication year - 2004
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.20044
Subject(s) - intracytoplasmic sperm injection , blastocyst , andrology , sperm , human fertilization , percoll , oocyte , biology , oocyte activation , embryogenesis , embryo , in vitro fertilisation , anatomy , medicine , in vitro , genetics
The objective of this study was to optimize intracytoplasmic sperm injection (ICSI), and to assess the effects of membrane‐damaged sperm on development of porcine oocytes following ICSI. For optimization of development following the ICSI process, sperm injected oocytes were activated 0.5–1.0 hr after ICSI with 1 × 30 μs pulse of 1.2, 1.7, 2.2, and 2.7 kV/cm DC in experiment 1. After 7‐days of culture ICSI oocytes activated with [×1] 2.2 kV/cm produced more blastocyts ( [×2] 34.4%, P < 0.05) than other treatment groups. In experiment 2, oocytes were activated with 1 × 30 μs pulse of 2.2 kV/cm at either 0, 1.5, 3, or 6 hr after ICSI. Oocytes activated 1.5 hr after [×3] ICSI yielded more blastocysts (27.6%) [M4] than in other treatments. In experiment 3, sperm were briefly exposed to 0.1% Triton X‐100 to induce membrane damage. Live‐dead staining of Percoll‐sorted untreated spermatozoa (frozen‐thawed) used in this study showed that over 96% were “alive” whereas none were “alive” after Triton X‐100 treatment. The rate of development to blastocyst of oocytes injected with Triton X‐100 treated sperm combined with electrical activation (EA) at 1 × 30 μs pulse of 2.2 kV/cm (EA, 40.0%) was the best, when compared with those injected with untreated sperm plus EA ( P < 0.05). In experiment 4, the development rate of oocytes to the blastocyst stage ( [×5] 32.1%) following injection of a sperm head only was not significantly different from that of oocytes injected with whole sperm (31.0%). In conclusion, we found that an intact membrane and tail structures of pig spermatozoa are not essential for embryo development by ICSI, and furthermore, dead porcine spermatozoa, at an early stage of necrosis caused by plasma membrane damage, support better embryo development than do live non‐damaged sperm. Mol. Reprod. Dev. 68: 96–102, 2004. © 2004 Wiley‐Liss, Inc.