Loss of Bmal1 decreases oocyte fertilization, early embryo development and implantation potential in female mice

SummaryBiological clock genes expressed in reproductive tissues play important roles in maintaining the normal functions of reproductive system. However, disruption of female circadian rhythm on oocyte fertilization, preimplantation embryo development and blastocyst implantation potential is still unclear. In this study, ovulation, in vivo and in vitro oocyte fertilization, embryo development, implantation and intracellular reactive oxygen species (ROS) levels in ovary and oviduct were studied in female Bmal1+/+ and Bmal1−/− mice. The number of naturally ovulated oocyte in Bmal1−/− mice decreased (5.2 ± 0.8 vs 7.8 ± 0.8, P < 0.001), with an increasing abnormal oocyte ratio (20.4 ± 3.5 vs 11.7 ± 2.0%, P = 0.001) after superovulation. Significantly lower fertilization rate and obtained blastocyst number were observed in Bmal1−/− female mice either mated with wild-type in vivo or fertilized by sperm from wild-type male mice in vitro (all P < 0.05). Interestingly, in vitro fertilization rate of oocytes derived from Bmal1−/− increased significantly compared with in vivo study (P < 0.01). After transferring blastocysts derived from Bmal1+/+ and Bmal1−/− female mice to pseudopregnant mice, the implantation sites of the latter decreased 5 days later (8.0 ± 0.8 vs 5.3 ± 1.0, P = 0.005). The intracellular ROS levels in the ovary on proestrus day and in the oviduct on metestrus day increased significantly in Bmal1−/− mice compared with that of Bmal1+/+ mice. Deletion of the core biological clock gene Bmal1 significantly decreases oocyte fertilization rate, early embryo development and implantation potential in female mice, and these may be possibly caused by excess ROS levels generated in ovary and oviduct.

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Oviductal response to gametes and early embryos in mammals

Reproduction ◽

10.1530/rep-16-0120 ◽

2016 ◽

Vol 152 (4) ◽

pp. R127-R141 ◽

Cited By ~ 34

Author(s):

Veronica Maillo ◽

Maria Jesus Sánchez-Calabuig ◽

Ricaurte Lopera-Vasquez ◽

Meriem Hamdi ◽

Alfonso Gutierrez-Adan ◽

...

Keyword(s):

Embryo Development ◽

Reproductive Tract ◽

Early Embryo ◽

Secretory Cells ◽

Oocyte Fertilization ◽

Early Embryos ◽

Significant Research ◽

Oviductal Fluid

The oviduct is a complex and organized thin tubular structure connecting the ovary with the uterus. It is the site of final sperm capacitation, oocyte fertilization and, in most species, the first 3–4days of early embryo development. The oviductal epithelium is made up of ciliary and secretory cells responsible for the secretion of proteins and other factors which contribute to the formation of the oviductal fluid. Despite significant research, most of the pathways and oviductal factors implicated in the crosstalk between gametes/early embryo and the oviduct remain unknown. Therefore, studying the oviductal environment is crucial to improve our understanding of the regulatory mechanisms controlling fertilization and embryo development. In vitro systems are a valuable tool to study in vivo pathways and mechanisms, particularly those in the oviducts which in livestock species are challenging to access. In studies of gamete and embryo interaction with the reproductive tract, oviductal epithelial cells, oviductal fluid and microvesicles co-cultured with gametes/embryos represent the most appropriate in vitro models to mimic the physiological conditions in vivo.

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Identification of a Novel Role for Endothelins within the Oviduct

Endocrinology ◽

10.1210/en.2009-1155 ◽

2010 ◽

Vol 151 (6) ◽

pp. 2858-2867 ◽

Cited By ~ 22

Author(s):

Myoungkun Jeoung ◽

Sungeun Lee ◽

Hee-kyung Hawng ◽

Yong-Pil Cheon ◽

Youn Kyung Jeong ◽

...

Keyword(s):

Epithelial Cells ◽

Embryo Development ◽

Early Embryo ◽

Receptor Subtypes ◽

Early Embryo Development ◽

Vitro Fertilization ◽

Protein Superfamilies ◽

Endothelin 3

Endothelins were first identified as potent vasoactive peptides; however, diversity in the biological function of these hormones is now evident. We have identified a novel role for endothelins: a requirement for these peptides within the oviduct during fertilization and/or early embryo development. In vivo, treatment after ovulation with a dual endothelin receptor antagonist (tezosentan) decreased the number of two-cell embryos that could be collected from within the oviducts. In vitro fertilization experiments showed that gamete viability and their ability to fertilize were not affected by treatment with this antagonist, suggesting that the effect observed in vivo was mediated by the oviduct itself. Expression of mRNA for all three isoforms of the endothelins and both receptor subtypes was detectable within the oviduct. Expression of mRNA for endothelin-3 was regulated by gonadotropins in epithelial cells of the oviduct and increased specifically within the isthmus of this structure. Immunostaining revealed localization of both endothelin receptors A and B to the columnar epithelial cells within the oviduct, suggestive of a local role for endothelins in the regulation of epithelial function and ultimately oviductal secretions. A microarray analysis revealed three likely endothelin-regulated protein networks for future analysis: the TGFβ, IL-10, and CCAAT/enhancer-binding protein superfamilies. Overall, these results suggest a novel and requisite role for endothelins within the oviduct during fertilization and/or early embryo development.

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Early embryonic development of bovine oocytes challenged with LPS in vitro or in vivo

Reproduction ◽

10.1530/rep-19-0316 ◽

2019 ◽

Vol 158 (5) ◽

pp. 453-463

Author(s):

Joao Alveiro Alvarado Rincón ◽

Patricia Carvalho Gindri ◽

Bruna Mion ◽

Ferronato Giuliana de Ávila ◽

Antônio Amaral Barbosa ◽

...

Keyword(s):

Embryonic Development ◽

Embryo Development ◽

Cumulus Cells ◽

Early Embryo ◽

Cleavage Rate ◽

Early Embryo Development ◽

Lps Challenge ◽

Bovine Oocytes

The aim of this study was to evaluate the effect of exposing bovine oocytes to lipopolysaccharides (LPS) in vivo and in vitro on early embryo development. In experiment 1, cumulus oocyte complexes (COCs, n = 700/group) were challenged with 0, 0.1, 1.0 or 5.0 μg/mL of LPS during in vitro maturation (IVM). Later, in vitro fertilization (IVF) and in vitro culture (IVC) were performed. In experiment 2, COCs (n = 200/group) matured and in vitro fertilized without LPS were subjected to IVC with the same doses of LPS from experiment 1. In experiment 3, heifers received two injections of saline solution (n = 8) or 0.5 μg/kg of LPS (n = 8) 24 h apart, and 3 days later, COCs were recovered and submitted to IVM, IVF, and IVC. In experiments 1 and 3, the expression of TLR4, TNF, AREG and EREG genes in cumulus cells was evaluated. Exposure to 1 and 5 μg/mL of LPS during IVM decreased nuclear maturation (39.4 and 39.6%, respectively) compared with control (63.6%, P < 0.05). Despite that, no effect on cleavage and blastocyst rates were observed. Exposure to LPS during IVC did not affect embryonic development. In vivo exposure to LPS decreased the in vitro cleavage rate (54.3 vs 70.2%, P = 0.032), but cleaved embryos developed normally. Number of cells per embryo and gene expression were not affected by the LPS challenge in any experiment. In conclusion, although in vitro exposure to LPS did not affect early embryo development, in vivo LPS exposure reduced cleavage rate.

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