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.

Links

Publisher Full Text

Authors

Seekallu SV, Toosi BM, Grazul-Bilska AT, Rawlings NC

Institution

Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.

Source

Reproduction (Cambridge, England) 140:4 2010 Oct pg 559-68

MeSH

Animals
Connexin 43
Dinoprost
Estradiol
Estrous Cycle
Factor VIII
Female
Follicle Stimulating Hormone
Granulosa Cells
Immunohistochemistry
Medroxyprogesterone Acetate
Ovarian Follicle
Ovulation
Progesterone
Proliferating Cell Nuclear Antigen
RNA, Messenger
Reverse Transcriptase Polymerase Chain Reaction
Sheep
Theca Cells
Vascular Endothelial Growth Factor A

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

20634390