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Developmental competence of porcine parthenogenetic embryos relative to embryonic chromosomal abnormalities
Author(s) -
Hao YanHong,
Lai LiangXue,
Liu ZhongHua,
Im GiSun,
Wax David,
Samuel Melissa,
Murphy Clifton N.,
Sutovsky Peter,
Prather Randall S.
Publication year - 2006
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.20358
Subject(s) - blastocyst , embryo , biology , andrology , zygote , parthenogenesis , embryogenesis , embryo culture , in vitro maturation , anatomy , genetics , medicine
Parthenogenetically activated (PA) embryos exhibit delayed development, a lower blastocyst rate, and less successful development in vitro compared to in vitro fertilized (IVF) embryos. To investigate the possible mechanisms for unsuccessful parthenogenetic development, this study analyzed the chromosome abnormalities and developmental potential of porcine PA embryos. Mature oocytes were electrically activated and cultured in Porcine Zygote Medium‐3 (PZM 3 ) supplemented with 3 mg/ml BSA for 6, 7, or 8 days. The percentage of PA blastocysts was lower than that of IVF embryos on days 6 and 7 (16.4 ± 7.4 vs. 28.7 ± 3.7; 10.9 ± 2.8 vs. 21.5 ± 4.7, P < 0.05; respectively), and the PA blastocysts had significantly fewer nuclei than IVF blastocysts (23.2 ± 1.8 vs. 29.7 ± 0.8; 29.7 ± 3.3 vs. 32.0 ± 2.4, P < 0.05). The percentage of abnormal PA embryos (including embryos with condensed nuclei, arrested embryos and fragmented embryos) was higher than that of IVF embryos (PA: 52.9 ± 12.8 vs. 16.4 ± 7.4 on day 6), and increased with culture time (71.9 ± 12.1 vs. 10.9 ± 2.8. on day 7,and 75.0 ± 22.6 vs. 12.1 ± 2.3 on day 8, P < 0.05). The Day‐6 PA blastocysts (n = 147) were divided into three classes according to the total number of nuclei (<20, 20–39, >40) and into three groups according to the morphological diameter (<150, 150–180, >180 µm). Of the haploid blastocysts, 56.1% had less than 20 nuclei, and 71.5% were less than 150 µm in diameter. Of all (114) blastocysts suitable for analysis, 55.5% displayed chromosomal abnormalities. Among chromosomal abnormalities in PA blastocysts, haploid blastocysts were most prevalent (43.6%), while polyploidy (4.4%) and mixoploidy (7.7%) embryos were less prevalent. Chromosomal abnormalities of porcine PA embryos might contribute to a higher rate of abnormal embryonic development. We suggest that a careful consideration should be given when using the blastocysts with smaller size, and establishing the optimum culture condition for PA embryos development in vitro. Mol. Reprod. Dev. © 2005 Wiley‐Liss, Inc.