TY - JOUR
T1 - Improvement in blastocyst quality by neurotensin signaling via its receptors in bovine spermatozoa during in vitro fertilization
AU - Umezu, Kohei
AU - Yajima, Risa
AU - Hiradate, Yuuki
AU - Yanai, Rin
AU - Numabe, Takashi
AU - Hara, Kenshiro
AU - Oikawa, Toshinori
AU - Tanemura, Kentaro
N1 - Funding Information:
The authors thank the staff at the Meat Inspection Office, Sen-dai, Japan. This work was supported by a Grant-in-Aid for JSPS Fellows (KAKENHI, grant No. JP17J02431). We thank Dr Masa-nori Koyago and Dr Keishi Mizutani (Livestock Improvement Association of Japan, Inc.) for providing the bovine testes; Dr You-suke Naniwa (Livestock Improvement Association of Japan, Inc.) for critical reading of the manuscript, and Charles Allan, PhD, from Edanz Group (www.edanzediting.com/ac) for editing a draft of this manuscript.
Publisher Copyright:
© 2019 by the Society for Reproduction and Development.
PY - 2019
Y1 - 2019
N2 - Previously, we reported that neurotensin (NT), which is expressed in the uterus and oviduct, enhanced bovine sperm capacitation and acrosome reactions. As NT mRNA expression in bovine oviducts increases dramatically in the follicular phase, we hypothesized that NT modulates fertilization and subsequent conception in cattle. The objective of this study was to evaluate the effect of NT on embryo development and blastocyst quality. The rate of embryo cleavage was significantly increased by the addition of NT to the fertilization medium. Furthermore, the total number of cells and numbers of cells in the inner cell mass of blastocysts were significantly increased by NT during in vitro fertilization (IVF). These results suggested that NT enhanced the efficiency of early bovine embryo development and blastocyst quality. The expression of NT receptors (NTRs) in sperm, testes, oocytes, and cumulus cells was evaluated to determine whether NT acted via NTRs in sperm alone or in both male and female reproductive cells during IVF. Immunocytochemistry and reverse transcription polymerase chain reaction revealed that NTR1 and NTR2 were expressed in sperm and testes, but not in oocytes and cumulus cells. We propose that NT selectively acts upon sperm via NTR1 and NTR2 during IVF to improve the cleavage rate and quality of blastocysts, which are important determinants of sperm quality for successful conception. This research supports our hypothesis that NT acts as a key modulator of fertilization and conception in cattle. Further studies are necessary to apply our findings to the industrial framework of bovine reproduction.
AB - Previously, we reported that neurotensin (NT), which is expressed in the uterus and oviduct, enhanced bovine sperm capacitation and acrosome reactions. As NT mRNA expression in bovine oviducts increases dramatically in the follicular phase, we hypothesized that NT modulates fertilization and subsequent conception in cattle. The objective of this study was to evaluate the effect of NT on embryo development and blastocyst quality. The rate of embryo cleavage was significantly increased by the addition of NT to the fertilization medium. Furthermore, the total number of cells and numbers of cells in the inner cell mass of blastocysts were significantly increased by NT during in vitro fertilization (IVF). These results suggested that NT enhanced the efficiency of early bovine embryo development and blastocyst quality. The expression of NT receptors (NTRs) in sperm, testes, oocytes, and cumulus cells was evaluated to determine whether NT acted via NTRs in sperm alone or in both male and female reproductive cells during IVF. Immunocytochemistry and reverse transcription polymerase chain reaction revealed that NTR1 and NTR2 were expressed in sperm and testes, but not in oocytes and cumulus cells. We propose that NT selectively acts upon sperm via NTR1 and NTR2 during IVF to improve the cleavage rate and quality of blastocysts, which are important determinants of sperm quality for successful conception. This research supports our hypothesis that NT acts as a key modulator of fertilization and conception in cattle. Further studies are necessary to apply our findings to the industrial framework of bovine reproduction.
KW - Blastocyst
KW - Bovine sperm
KW - Cumulus-oocyte complex
KW - In vitro fertilization
KW - Neurotensin
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U2 - 10.1262/jrd.2018-147
DO - 10.1262/jrd.2018-147
M3 - Article
C2 - 30662011
AN - SCOPUS:85064852630
VL - 65
SP - 147
EP - 153
JO - Journal of Reproduction and Development
JF - Journal of Reproduction and Development
SN - 0916-8818
IS - 2
ER -