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Growth hormone inhibits apoptosis in in vitro produced bovine embryos
Author(s) -
Kölle Sabine,
Stojkovic Miodrag,
Boie Gudrun,
Wolf Eckhard,
Sinowatz Fred
Publication year - 2002
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.1145
Subject(s) - biology , blastocyst , apoptosis , tunel assay , embryo , inner cell mass , terminal deoxynucleotidyl transferase , embryogenesis , andrology , embryonic stem cell , bovine somatotropin , endocrinology , oviduct , medicine , microbiology and biotechnology , hormone , genetics , growth hormone , gene
Growth hormone (GH) has recently been shown to exert distinct effects on the differentiation and metabolism of early embryos. Up to now, however, it is not clear whether GH is able to modulate apoptosis during early embryogenesis. Differential cell staining of 8‐day‐old bovine embryos cultured with 100 ng bovine recombinant GH (rbGH) per ml medium (synthetic oviduct fluid–polyvinylalcohol) demonstrated that GH significantly increased the number of inner cell mass (ICM) and trophectoderm cells in bovine expanded blastocysts. As shown by terminal deoxynucleotidyl transferase mediated dUTP labeling (TUNEL) supplementation of bGH decreased the percentage of 8‐day‐old embryos showing at least one apoptotic cell from 58 to 21%. The percentage of apoptotic cells in one blastocyst was significantly ( P < 0.01) reduced from 4.6 to 1.1% by GH treatment. Incubation of the embryos with 150 mM vanillylnonanamide induced apoptosis in all embryos. Whereas in control embryos 14% of the embryonic cells were TUNEL‐positive, the percentage of apoptotic cells declined to 2.7% in the GH treated embryos. Expression of immunoreactive bcl‐2 in blastocysts was not affected by GH treatment. Synthesis of the bax protein which is known to promote apoptosis was reduced in embryos cultured with GH. Our results suggest that GH acts as survival factor during in vitro culture and reduces apoptosis by altering the bax to bcl‐2 ratio during early embryogenesis. Mol. Reprod. Dev. 61: 180–186, 2002. © 2002 Wiley‐Liss, Inc.