Abstract
The developmental competence of oocytes during in vitro maturation (IVM) is compromised due to asynchronous nuclear and cytoplasmic maturation. To improve IVM efficiency, a pre-maturation culture or two-step maturation strategy has been established, involving meiosis arrest induced by pharmacological agents to provide oocytes with sufficient time to synchronize the maturation of the nucleus and cytoplasm. C-type natriuretic peptide (CNP), which has been demonstrated to function as an oocyte maturation inhibitor (OMI) in many species, provides a new alternative to improve the developmental capacity of oocytes matured in vitro. However, the effect of CNP on meiosis arrest and the maturation of goat oocytes remains unclear. In the present study, CNP was shown to function as an OMI in goat oocytes. CNP could temporarily maintain the meiotic arrest of goat oocytes cultured in vitro for 4 hours. This transient effect was partly due to the reduction of natriuretic peptide receptor 2 (Npr2). Estradiol could delay the decrease in Npr2 expression and prolong the duration of meiosis arrest up to 6 hours. Based on the above results, a two-step method was established for goat oocyte maturation, in which the oocyte maturation rate was significantly increased. After parthenogenetic activation, the cleavage rate, blastocyst rate and total cell number of blastocysts were significantly improved. Our results suggested that CNP can be used to delay meiotic resumption and enhance the developmental competence of goat oocytes matured in vitro.
Highlights
In mammalian animals, oocytes in antral follicles are arrested at meiotic prophase, known as the germinal vesicle (GV) stage, for a prolonged period [1]
Because the meiotic arrest function of C-type natriuretic peptide (CNP) depends on its receptor natriuretic peptide receptor 2 (Npr2), the expression of Npr2 mRNA in ovarian follicles at different developmental stages was determined
These results suggested that 100- and 150-ng/mL CNP could only temporarily inhibit the meiotic resumption of goat oocytes
Summary
Oocytes in antral follicles are arrested at meiotic prophase, known as the germinal vesicle (GV) stage, for a prolonged period [1]. Studies have suggested that oocyte maturation inhibitor (OMI) can be found in follicle fluid and maintains meiotic arrest [2]. CNP Improved Maturation and Developmental Competence of Goat Oocytes follicle fluid. Natriuretic peptide receptor 2 (Npr2), the receptor for CNP, is mainly expressed by cumulus cells. The binding of CNP to Npr increases the cyclic guanosine monophosphate (cGMP) level in cumulus cells. CGMP diffuses into oocytes through gap junctions and inhibits the activity of phosphodiesterase 3A (PDE3A), resulting in the prevention of cyclic adenosine monophosphate (cAMP) degradation. In response to the preovulatory luteinizing hormone (LH) surge, meiosis resumes by decreasing the expression of CNP and Npr and reducing the guanylyl cyclase activity of Npr2 [10,11]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
