Functional and morphological changes in bovine corpus luteum during full and parcial luteolysis and luteal feature to low dose of cloroprostenol sodium during estrous cycle

Author(s)

Eduardo Trevisol

• Document type: Doctoral Thesis
• Press: Botucatu. 2015-05-14.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Medicina Veterinária e Zootecnia. Botucatu
• Defense date: 2014-09-02
• Advisor: João Carlos Pinheiro Ferreira

Abstract

We aimed describe the CL characteristics during partial luteolysis, in different days of estrous cycle, after cloprostenol sodium low-dose challenge. Therefore, two projects were conduct and describe in two articles. In the first article, 32 cows were submitted to ovulation synchronization (Ovsunch +P4), 28 cows ovulated between 24 and 32 hours (h) after last GnRH (Day 0) of ovulation synchronization protocol, and were used in the project. At D6, cows were randomly divided in three treatments (moment 0): Control (2 mL of saline 0.9%; IM, n=10), 2XPGF (two doses of 500 μg of cloprostenol sodium with 2 hours interval, n=8) and 1/6PGF (83.33 μg of cloprostenol sodium, IM, n=10). Blood samples and luteal volume were collect before treatments and every 8 h, during 48 h of observations. We also collect two CL biopsies at 24 and 40 h post-treatments. The data was considered statically different when P < 0.05. Animals from 2XPGF had progesterone concentration (P4) decreased 16 h after treatment and it remain low until 48 h after treatment. In 1/6PGF, we observe a partial luteolysis, with decrease on circulating P4 and luteal volume 16 h, after that, we observe an increase in the next moments. The COX-2 and PGDH staining were more intense at 24 and 40 h, however the staining for StAR was intense only on 40 h moment. Still in 1/6PGF treatment, the luteal volume also decrease after 24 h and this moment was characterized by large luteal cells (LLC) minor area than Control, also some positive cell for FAS and FAS-L staining. In the next moments, luteal volume increase as well as cell area tend increase. In the second article, 39 cows were submitted to ovulation protocol (last GnRH = D0), 34 ovulated between 24 and 32 h after GnRH of protocol. The cows were synchronized in a way that data collect were at the same day. Each estrous cycle day were submitted in the same 3 treatments described in Article I: D7 (n=5/2XPGF, n=5/1/6PGF e n=6/control) and ... (AU)

• FAPESP's process: 11/20449-7 - Role of LH during induced luteolysis and characterization of luteal sensitivity to PGF2alpha during estrus cycle and treatment with IFNt
• Grantee: Eduardo Trevisol
• Support Opportunities: Scholarships in Brazil - Doctorate