Endocrine, molecular and ultrasonography characterization of the ovarian activity after the treatment with different inductor hormones of ovulation and during the complete or partial luteolysis in mares

• Grant number: 12/12288-6
• Support Opportunities: Regular Research Grants
• Start date: December 01, 2012
• End date: May 31, 2015
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Cezinande de Meira
• Grantee: Cezinande de Meira
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Associated researchers: José Buratini Junior

Abstract

The purpose of the present study will be: 1) to evaluate the ovulatory inductors effects on the follicular hemodynamics and plasma LH concentration, 2) to describe the effect of sub-doses of hCG on the functionality of the corpus luteum (CL), and 3) to quantify the expression of angiogenic factors of the CL and the plasma hormonal concentration throughout the luteolysis total and partial. In Experiment 1, follicular vascularity and concentration of LH will be evaluated during the last 48 hours previously to ovulation using 24 mares (n=8 mares/group) treated with 2.500UI of hCG, 1.5mg of deslorelin or 2mL of saline. In Experiment 2, 24 mares (n=6 mares/group; 4 groups) will be used to determine the effect of sub-doses of hCG on the vascular perfusion of pre-ovulatory follicles. In Experiment 3, CL functional and structural status post-treatment with hCG will be study. 60 mares will be divided according to the day of treatment and dose of hCG. In Experiments 4 and 5, a total of 56 mares (28 mares and 4 groups/experiment; n=7 mares/group) will be treated with saline or different doses of PGF2± during the luteogenesis (Exp.4) and CL maintenance phases (Exp.5). The end point evaluated will be luteal vascularity and plasma progesterone (P4) concentration. Doppler ultrasonography exam and blood samples will be performed every 24 hours from day of ovulation (D0) until day of luteolysis. Additionally, end points will be evaluated every 6 hours and during the first 48 hours post-treatment (h0). In Experiment 6, five groups of mares (n=7 mares/group) will be treated with saline or with the dose of PGF2± required to induce luteolysis total or partial during the luteogenesis (D2) or luteal maintanance phase (D8). Blood sample will be collected hourly during the first 48 hours post-treatment to measure plasma concentration of P4, PGFM, prolactin, LH, estradiol and oxytocin. In Experiment 7, luteal fragments of 72 mares treated with different doses of PGF2± will be collected by biopsy to quantify the genic and proteic expression of angiogenic factors (VEGFA, VEGFR-1, VEGFR-2, Ang-1, Ang-2, receptor Tie-2, NO, eNOS, iNOS, GUCY1B3 e HIF-1±) in the luteal tissue during the regression total or parcial using RT-PCR and Western blotting. Byopsis of the CL and blood sample will be performed on hours 0, 6 and 24 post-treatment. A single sample of luteal tissue per mare will be collected. (AU)