Expression of hypoxia-inducible factors and vascular endothelial growth factor during pregnancy in the feline uterus Ozgecan Korkmaz Agaoglu a, * , Ali Reha Agaoglu b , Aydin Guzeloglu c , Ercan Kurar c , Seyit Ali Kayis d , Ozlem Ozmen e , Sabine Schäfer-Somi f , Selim Aslan g a Department of Animal Science, Faculty of Veterinary Medicine, Mehmet Akif Ersoy University, Burdur, Turkey b Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Mehmet Akif Ersoy University, Burdur, Turkey c Department of Genetics, Faculty of Veterinary Medicine, Selcuk University, Konya, Turkey d Department of Biostatistics, Faculty of Medicine, Karabuk University, Karabuk, Turkey e Department of Pathology, Faculty of Veterinary Medicine, Mehmet Akif Ersoy University, Burdur, Turkey f Centre for Artificial Insemination and Embryo Transfer, University of Veterinary Medicine, Vienna, Austria g Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Ankara University, Ankara, Turkey article info Article history: Received 14 August 2014 Received in revised form 3 February 2015 Accepted 5 February 2015 Keywords: Hypoxia-inducible factor Feline Uterus Real-time PCR Vascular endothelial growth factor abstract Hypoxia-inducible factors (HIFs) and vascular endothelial growth factor (VEGF) have critical roles during the development of the fetomaternal unit. The HIFs regulate placen- tation and vascularization by stimulation of VEGF gene expression. This study aimed to investigate the expression profiles of HIF gene family and VEGF in the cat uterus during pregnancy. Tissue samples of the whole uterine wall were collected after ovariohyster- ectomy and allocated to the following groups: embryo positive (group 1 [G1], n ¼ 7, 7 days after mating), early pregnancy (group 2 [G2], n ¼ 7, 20 days after mating), mid-pregnancy (group 3 [G3], n ¼ 7, 24 days after mating), late pregnancy (group 4 [G4], n ¼ 7, 30–45 days after mating), and oocyte positive groups (group 5 [G5], n ¼ 7, 7 days after induction of ovulation with GnRH analog). Relative mRNA levels were determined by real-time poly- merase chain reaction. As housekeeping gene, glyceraldehyde-3-phosphate dehydroge- nase was used. The relative gene expression of HIF1A in G5 was found to be significantly higher than that of other groups (G1, G2, G3, and G4) (P < 0.05). In addition, the expression of HIF2A in G5 was higher than that of G1 and HIF2A gene expression at placentation sites of G4 was higher than in G1, G2, and G3 (P < 0.05). Immunohistochemistry indicated that HIF1A, HIF2A, and VEGF expressions were observed in different cell types of uterine and placental tissues in late pregnancy and oocyte groups. The expression of HIF3A did not change significantly in any group investigated. These observations suggest that HIFs and VEGF may play a role in the establishment and development of pregnancy. Ó 2015 Elsevier Inc. All rights reserved. 1. Introduction Development of placenta is a complex process and occurs as a result of a complex interaction between embryo and uterus. This process is regulated by many factors, such as cytokines [1], growth factors [2], steroid hormones [3], prostaglandins [4], and environmental conditions [5] of This work was presented in the 18th European Society of Domestic Animal Reproduction, Helsinki, Finland. * Corresponding author. Tel.: þ90 248 2132074; fax: þ90 248 2132001. E-mail address: ozgecanagaoglu@mehmetakif.edu.tr (O.K. Agaoglu). Contents lists available at ScienceDirect Theriogenology journal homepage: www.theriojournal.com 0093-691X/$ – see front matter Ó 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.theriogenology.2015.02.009 Theriogenology 84 (2015) 24–33