title: Effect of bone morphogenetic protein-4 on in vitro growth, steroidogenesis and subsequent developmental competence of the oocyte-granulosa cell complex derived from bovine early antral follicles.
abstract: BACKGROUND
  Bone morphogenetic proteins (BMPs) play important regulatory roles during folliculogenesis. Theca-derived BMP-4 may be beneficial to in vitro growth culture of early antral follicle-derived oocyte-granulosa cell complexes (OGCs), which is lacking in theca-derived products.
  
  
  METHODS
  BMP-4 (0 [control], 10 and 50 ng/mL) was added to growth culture medium. Growth, steroidogenesis and the subsequent developmental competence of OGCs derived from bovine early antral follicles (0.5-1 mm) were examined.
  
  
  RESULTS
  At 4, 8 and 12 days of growth culture, progesterone production by granulosa cells was suppressed by the addition of BMP-4 compared to the control (P < 0.05). At 12 days, both the OGC survivability and granulosa cell number in the 50 ng/mL BMP-4 treated group were lower than those of control (48.2 % vs. 67.8 %; 4.96 × 10(4) vs. 8.5 × 10(4) cells; P < 0.05, respectively), while no difference was found between 10 ng/mL and the control. The mean diameters of granulosa cell in the BMP-4 treated groups were smaller than that of the control (P < 0.05). However, the granulosa cell viability, oocyte diameter, oocyte nuclear maturation rate and normal fertilization rate were similar in all of the experimental groups, regardless of the amount of BMP-4 addition (P ˃ 0.05). BMP-4 treated in vitro-grown oocytes showed lower blastocyst rates than untreated ones (P < 0.05).
  
  
  CONCLUSIONS
  BMP-4 addition during in vitro growth culture suppressed progesterone production and decreased the diameter of granulosa cells, suggesting its effect on steroidogenesis; importantly, it did not affect oocyte growth, nuclear maturation and fertilization. However, BMP-4 impaired subsequent embryonic development, and in higher concentration (50 ng/mL) even compromised OGC viability by suppressing proliferation of granulosa cells.
authors.affiliation: Laboratory of Theriogenology, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, 060-0818, Japan. young@vetmed.hokudai.ac.jp.
authors.forename: Yinghua
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Laboratory of Theriogenology, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, 060-0818, Japan. c.kanno@vetmed.hokudai.ac.jp.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Kanno
authors.affiliation: Laboratory of Theriogenology, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, 060-0818, Japan. huang@vetmed.hokudai.ac.jp.
authors.forename: Weiping
authors.initials: W
authors.lastname: Huang
authors.affiliation: Laboratory of Theriogenology, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, 060-0818, Japan. ricafo@vetmed.hokudai.ac.jp.
authors.forename: Sung-Sik
authors.initials: SS
authors.lastname: Kang
authors.affiliation: Laboratory of Theriogenology, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, 060-0818, Japan. yoji-y@vetmed.hokudai.ac.jp.
authors.forename: Yojiro
authors.initials: Y
authors.lastname: Yanagawa
authors.affiliation: Laboratory of Theriogenology, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, 060-0818, Japan. mnaga@vetmed.hokudai.ac.jp.
authors.forename: Masashi
authors.initials: M
authors.lastname: Nagano
mesh_terms: D000818:Animals; D055415:Bone Morphogenetic Protein 4 / Q000494:pharmacology*; D002417:Cattle; D018929:Cell Culture Techniques; D048429:Cell Size / Q000187:drug effects; D005260:Female; D005306:Fertilization; D006107:Granulosa Cells / Q000166:cytology / Q000187:drug effects*; D009865:Oocytes / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development; D006080:Ovarian Follicle / Q000166:cytology / Q000187:drug effects*
chemical_list: D055415:Bone Morphogenetic Protein 4