The periovulatory endocrine milieu affects the uterine redox environment in beef cows

Author(s)

Ramos, Roney S. ^[1] ; Oliveira, Milena L. ^[1] ; Izaguirry, Aryele P. ^[2] ; Vargas, Laura M. ^[2] ; Soares, Melina B. ^[2] ; Mesquita, Fernando S. ^[3] ; Santos, Francielli W. ^[2] ; Binelli, Mario ^[1]

Affiliation

^[1] Univ Sao Paulo, Sch Vet Med & Anim Sci, Dept Anim Reprod, BR-13635900 Pirassununga, SP - Brazil

^[2] Fed Univ Pampa, Lab Reprod Biotechnol Biotech, Uruguaiana - Brazil

^[3] Fed Univ Pampa, Sch Vet Med, Uruguaiana - Brazil

• Document type: Journal article
• Source: Reproductive Biology and Endocrinology; v. 13, MAY 10 2015.
• Web of Science Citations: 22

Abstract

Background: In cattle, recent studies have shown positive associations between pre-ovulatory concentrations of estradiol (E2), progesterone (P4) at early diestrus and fertility. However, information on cellular and molecular mechanisms through which sex steroids regulate uterine function to support early pregnancy is lacking. Based on endometrial transcriptome data, objective was to compare function of the redox system in the bovine uterus in response to different periovulatory endocrine milieus. Methods: We employed an animal model to control growth of the pre-ovulatory follicle and subsequent corpus luteum (CL). The large follicle-large CL group (LF-LCL, N = 42) presented greater levels of E2 on the day of GnRH treatment (D0; 2.94 vs. 1.27 pg/mL; P = 0.0007) and P4 at slaughter on D7 (3.71 vs. 2.62 ng/mL, P = 0.01), compared with the small follicle-small CL group (SF-SCL, N = 41). Endometrium and uterine washings (N = 9, per group) were collected for analyses of variables associated with the uterine redox system. Results: The SF-SCL group had lower endometrial catalase (0.5 vs. 0.79 U/mg protein, P < 0.001) and glutathione peroxidase (GPx; 2.0 vs. 2.43 nmol beta-nicotinamide adenine dinucleotide phosphate reduced/min/mg protein, P = 0.04) activity, as well as higher lipid peroxidation (28.5 vs. 17.43 nmol malondialdehyde/mg of protein, P < 0.001) and superoxide dismutase (SOD) activity (44.77 vs. 37.76 U; P = 0.04). There were no differences in the endometrial reactive species (RS) or glutathione (GSH) concentrations between the groups. The uterine washing samples showed no differences in the concentrations of RS or GSH or in total SOD activity (P > 0.1). Additionally, catalase, GPx4, SOD1 and SOD2 gene expression was lower in the SF-SCL group than in the LF-LCL group. Conclusions: We concluded that the intrauterine environment of cows from the LF-LCL group exhibited higher antioxidant activity than that of the cows from the SF-SCL group. We speculate that uterine receptivity and fertility are associated with an optimal redox environment, such as that present in the animals in the LF-LCL group. (AU)

• FAPESP's process: 12/23532-5 - Effect of the periovulatory endocrine milieu on polyamines synthesis pathway in endometrium during the first week of the estrous cycle in cattle
• Grantee: Roney dos Santos Ramos
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 11/03226-4 - Signatures of receptivity
• Grantee: Mario Binelli
• Support Opportunities: Research Projects - Thematic Grants