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BAPTA‐AM dramatically improves maturation and development of bovine oocytes from grade‐3 cumulus‐oocyte complexes
Author(s) -
Hu Hongmei,
Mo Xianhong,
Li Xue,
Fu Xiangwei,
Hou Yunpeng
Publication year - 2018
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.22936
Subject(s) - oocyte , blastocyst , bapta , human fertilization , andrology , biology , in vitro maturation , oocyte activation , embryogenesis , embryo , endocrinology , intracellular , microbiology and biotechnology , anatomy , medicine
Intracellular free calcium ([Ca 2+ ] i ) is essential for oocyte maturation and early embryonic development. Here, we investigated the role of [Ca 2+ ] i in oocytes from cumulus‐oocyte complexes (COCs) with respect to maturation and early embryonic development, using the calcium‐buffering agent BAPTA‐AM (1,2‐bis[2‐aminophenoxy]ethane‐ N,N,N′,N′ ‐tetraacetic acid tetrakis [acetoxymethyl ester]). COCs were graded based on compactness of the cumulus mass and appearance of the cytoplasm, with Grade 1 indicating higher quality and developmental potential than Grade 3. Results showed that: (i) [Ca 2+ ] i in metaphase‐II (MII) oocytes from Grade‐3 COCs was significantly higher than those from Grade‐1 COCs, and was significantly reduced by BAPTA‐AM; (ii) nuclear maturation of oocytes from Grade‐3 COCs treated with BAPTA‐AM was enhanced compared to untreated COCs; (iii) protein abundance of Cyclin B and oocyte‐specific Histone 1 (H1FOO) was improved in MII oocytes from Grade‐3 COCs treated with BAPTA‐AM; (iv) Ca 2+ transients were triggered in each group upon fertilization, and the amplitude of [Ca 2+ ] i oscillations increased in the Grade‐3 group upon treatment with BAPTA‐AM, with the magnitude approaching that of the Grade‐1 group; and (v) cleavage rates and blastocyst‐formation rates were improved in the Grade‐3 group treated with BAPTA‐AM compared to untreated controls following in vitro fertilization and parthenogenetic activation. Therefore, BAPTA‐AM dramatically improved oocyte maturation, oocyte quality, and embryonic development of oocytes from Grade‐3 COCs.