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Intracellular cathepsin B activity is inversely correlated with the quality and developmental competence of bovine preimplantation embryos
Author(s) -
Balboula A.Z.,
Yamanaka K.,
Sakatani M.,
Hegab A.O.,
Zaabel S.M.,
Takahashi M.
Publication year - 2010
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.21250
Subject(s) - blastocyst , biology , andrology , cathepsin b , embryo , cathepsin , embryogenesis , embryo culture , embryo quality , zygote , human fertilization , tunel assay , microbiology and biotechnology , immunohistochemistry , immunology , anatomy , enzyme , biochemistry , medicine
Recently, the activity of cathepsins B was found to be correlated inversely with the developmental competence of bovine oocytes. In this study, we investigated (1) the role of intracellular cathepsin B expression and developmental competence as well as the quality of bovine preimplantation embryos, and (2) the effect of cathepsin B inhibitor (E‐64) during in vitro culture (IVC) on the development and quality of bovine embryos. After in vitro fertilization (IVF) followed by IVC for 7 days, good and poor quality embryos classified by morphology and developmental rate on days 2, 4, and 7 were assessed for cathepsin B expression and activity. To investigate the effect of cathepsin B inhibition on embryonic development, putative zygotes were cultured with or without E‐64, followed by evaluation of cleavage and blastocyst rates on days 2 and 7, respectively. Embryonic quality was evaluated by both TUNEL staining and total cell number in day‐7 blastocysts. In each developmental stage, cathepsin B expression and activity were significantly higher in poor quality embryos than good quality ones. Moreover, addition of E‐64 during IVC significantly increased both the blastocyst rate and the total cell number. TUNEL staining revealed that inhibition of cathepsin B significantly decreased the number of apoptotic nuclei in day‐7 blastocysts. These results indicate that cathepsin B activity can be useful as a marker for inferior quality embryos. Moreover, inhibition of cathepsin B greatly improves the developmental competence of preimplantation embryos and increases the number of good quality embryos. Mol. Reprod. Dev. 77:1031–1039, 2010. © 2010 Wiley‐Liss, Inc.