title: Steady-state level of insulin-like growth factor-I (IGF-I) receptor mRNA and the effect of IGF-I on the in vitro culture of caprine preantral follicles.
abstract: The objectives were to quantify insulin-like growth factor receptor-1 (IGFR-1) mRNA in preantral follicles on Days 0 and 18 of in vitro culture in the presence or absence of FSH, and to evaluate the effects of IGF-I on the rate of normal follicles, antral cavity formation, and in vitro growth and maturation of caprine oocytes on Days 0, 6, 12, and 18 of culture. The expression of IGFR-1 was analyzed using real-time RT-PCR before and after follicle culture. Preantral follicles were isolated from the cortex of caprine ovaries and individually cultured for 18 d in the presence or absence of bovine IGF-I (50 or 100 ng/mL). At the end of the culture period, the oocytes were submitted to IVM. The expression of IGFR-1 mRNA in preantral follicles cultured in vitro only approached being significantly higher in follicles supplemented with FSH when compared to follicles immediately after recovery (P<0.06) and cultured without FSH (P<0.1). There was a higher (P<0.05) percentage of normal follicles on Days 6, 12, and 18 of culture in IGF-I 50 (97, 92, 67%, respectively) and IGF-I 100 (100, 90, 80%) groups versus the control (90, 64, 36%). In addition, the rate of antrum formation at 6 and 12 d of culture was higher (P<0.05) in IGF-I groups (IGF-I 50: 72 and 90% and IGF-I 100: 69 and 85%) than the control group (41 and 59%). After 18 d of culture, the percentages of grown oocytes acceptable for IVM were higher (P<0.05) in follicles cultured in the presence of IGF-I (82 vs 49%). Furthermore, follicles cultured in the presence of IGF-I 50 and IGF-I 100 had higher (P<0.05) meiotic resumption rates (63 and 66%, respectively) than the control group (11%). In conclusion, treatment with FSH tended to increase IGFR-1 mRNA expression during the in vitro culture of preantral follicles and the addition of IGF-I to the culture medium clearly improved the in vitro development of caprine preantral follicles.
authors.affiliation: Laboratory of Manipulation of Oocytes Enclosed in Preantral Follicles (LAMOFOPA), Veterinary Faculty, State University of Ceará, Av. Paranjana, 1700, Campus do Itaperi, Fortaleza, 60740-000, CE, Brazil. dmmvet@hotmail.com
authors.forename: D M
authors.initials: DM
authors.lastname: Magalhães-Padilha
authors.forename: A B G
authors.initials: AB
authors.lastname: Duarte
authors.forename: V R
authors.initials: VR
authors.lastname: Araújo
authors.forename: M V A
authors.initials: MV
authors.lastname: Saraiva
authors.forename: A P
authors.initials: AP
authors.lastname: Almeida
authors.forename: G Q
authors.initials: GQ
authors.lastname: Rodrigues
authors.forename: M H T
authors.initials: MH
authors.lastname: Matos
authors.forename: C C
authors.initials: CC
authors.lastname: Campello
authors.forename: J R
authors.initials: JR
authors.lastname: Silva
authors.forename: M O
authors.initials: MO
authors.lastname: Gastal
authors.forename: E L
authors.initials: EL
authors.lastname: Gastal
authors.forename: J R
authors.initials: JR
authors.lastname: Figueiredo
mesh_terms: D000818:Animals; D002417:Cattle; D005260:Female; D006041:Goats / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects; D006080:Ovarian Follicle / Q000187:drug effects* / Q000254:growth & development; D012333:RNA, Messenger / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000235:genetics / Q000378:metabolism*; D046509:Tissue Culture Techniques / Q000662:veterinary*
chemical_list: D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1