title: Effect of C-type natriuretic peptide pretreatment on in vitro bovine oocyte maturation.
abstract: C-type natriuretic peptide (CNP) has been considered as a physiological meiotic inhibitor that stimulates the cGMP production by cumulus cell natriuretic peptide receptor 2 (NPR2), which inhibits oocyte phosphodiesterase type 3 activity and increases cAMP. In this study, we explored the effect of CNP pretreatment on the in vitro maturation (IVM) of bovine oocytes by examining changes in cleavage rate, blastocyst formation, mitochondrial DNA (mtDNA) copy number, reactive oxygen species (ROS) level, glutathione (GSH) content, and redox state. Our results showed that 200 nM CNP could effectively maintain meiotic arrest of bovine oocytes in vitro within 6 h. The two-step IVM system in which oocytes were pretreated with 200 nM CNP for 6 h and then cultured IVM for 28 h yielded a significantly (P < 0.05) increased blastocyst rate and cell number after in vitro fertilization (IVF) while compared to the conventional one-step IVM method. In addition, in comparison with the conventional 24-h matured oocyte, oocytes pretreated with 200 nM CNP for 6 h followed by 28 h IVM resulted in significantly (P < 0.05) higher mtDNA copy number and ROS levels in oocytes, while GSH level significantly (P < 0.05) decreased. Remarkably, regardless of treatment, no changes were observed in FAD++, NAD(P)H autofluorescence intensity, and redox ratio (FAD++/NAD(P)H) within the oocytes, maintaining a healthy metabolic equilibrium of redox throughout the two-step IVM. In conclusion, these results indicate that CNP pretreatment could dramatically improve the quality of bovine oocytes during in vitro maturation.
authors.affiliation: Key Laboratory of Animal Genetics, Breeding and Reproduction, College of Animal Science, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia, 010018, China.
authors.forename: Tong
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Animal Genetics, Breeding and Reproduction, College of Animal Science, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia, 010018, China.|Wulanchabu Medical College, Wulanchabu, Inner Mongolia, 012000, China.
authors.forename: Chunqiang
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Animal Genetics, Breeding and Reproduction, College of Animal Science, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia, 010018, China.|Basic Medical College, Inner Mongolia Medical University, Hohhot, Inner Mongolia, 010110, China.
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Fan
authors.affiliation: Key Laboratory of Animal Genetics, Breeding and Reproduction, College of Animal Science, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia, 010018, China.
authors.forename: Ruilan
authors.initials: R
authors.lastname: Li
authors.affiliation: Key Laboratory of Animal Genetics, Breeding and Reproduction, College of Animal Science, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia, 010018, China. zjxcau@163.com.
authors.forename: Jiaxin
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000187:drug effects; D002417:Cattle; D047108:Embryonic Development / Q000187:drug effects; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods; D059471:In Vitro Oocyte Maturation Techniques / Q000379:methods*; D008540:Meiosis / Q000187:drug effects; D020098:Natriuretic Peptide, C-Type / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects / Q000254:growth & development*; D009866:Oogenesis / Q000235:genetics*
chemical_list: D020098:Natriuretic Peptide, C-Type
keywords: Bovine oocyte; C-type natriuretic peptide; GSH; Mitochondrial DNA; ROS; Redox balance