title: Markers of ovarian antral follicular development in sheep: comparison of follicles destined to ovulate from the final or penultimate follicular wave of the estrous cycle.
abstract: Treatment of non-prolific western white-faced ewes with prostaglandin F(2α) (PGF(2α)) and medroxyprogesterone acetate (MAP) increases the ovulation rate as a result of ovulations from the penultimate wave in addition to the final wave of the cycle. The objective of the current study was to evaluate the expression of markers of vascularization/angiogenesis, a marker of intercellular communication, and cellular proliferation and apoptosis in follicles from the penultimate and final waves. On day 8 of the estrous cycle, 15 ewes were administered a single injection of PGF(2α) and an intravaginal MAP sponge, which remained in place for 6 days. Two days after sponge removal, ovaries which contained follicles from the penultimate and final waves were collected and processed for immunohistochemistry followed by image analysis, and for quantitative real-time RT-PCR. Expression of factor VIII (marker of vascularization), proliferating cell nuclear antigen, and GJA1 (Cx43; marker of gap junctional communication) was greater (P<0.05) in follicles from the final wave compared with follicles from the penultimate wave. For theca cells, mRNA expression for vascular endothelial growth factor (VEGF) was greater (P<0.05) and tended to be greater (P≤0.1 and ≥0.05) for GJA1 and endothelial nitric oxide synthase in follicles from the final wave compared with follicles from the penultimate wave. For granulosa cells, the mRNA expression for GJA1 was greater (P<0.05) and tended to be greater (P≤0.1 and ≥0.05) for VEGF in follicles from the final wave compared with follicles from the penultimate wave. In conclusion, extension of the lifespan of follicles in the penultimate wave reduces follicular viability in the ewe.
authors.affiliation: Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Srinivas V
authors.initials: SV
authors.lastname: Seekallu
authors.forename: Behzad M
authors.initials: BM
authors.lastname: Toosi
authors.forename: Anna T
authors.initials: AT
authors.lastname: Grazul-Bilska
authors.forename: Norman C
authors.initials: NC
authors.lastname: Rawlings
mesh_terms: D000818:Animals; D018031:Connexin 43 / Q000235:genetics / Q000502:physiology; D015237:Dinoprost / Q000494:pharmacology; D004958:Estradiol / Q000032:analysis; D030762:Estrous Cycle / Q000502:physiology*; D005169:Factor VIII / Q000235:genetics / Q000502:physiology; D005260:Female; D005640:Follicle Stimulating Hormone / Q000502:physiology*; D006107:Granulosa Cells / Q000502:physiology; D007150:Immunohistochemistry / Q000662:veterinary; D017258:Medroxyprogesterone Acetate / Q000494:pharmacology; D006080:Ovarian Follicle / Q000502:physiology*; D010060:Ovulation / Q000502:physiology*; D011374:Progesterone / Q000097:blood; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000502:physiology; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012756:Sheep / Q000502:physiology*; D013799:Theca Cells / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000502:physiology
chemical_list: D018031:Connexin 43; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D011374:Progesterone; D004958:Estradiol; D005169:Factor VIII; D005640:Follicle Stimulating Hormone; D015237:Dinoprost; D017258:Medroxyprogesterone Acetate