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| Author(s): |
Antenor Pereira Bonfim Neto
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) |
| Defense date: | 2014-09-12 |
| Examining board members: |
Paula de Carvalho Papa;
Mario Binelli;
Maria Denise Lopes
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| Advisor: | Paula de Carvalho Papa |
| Abstract | |
The 17β-estradiol (E2) plays an important role in the reproductive function and female fertility, however, its action is extended to most tissues. Knowing that E2 has pleiotropic roles in different organs and tissues, and that might be involved in both cell death and proliferation, our hypothesis is that E2 is one of the triggers of luteal regression in non-pregnant bitches. To test our hypothesis, corpora lutea (CL) from 28 dogs on days 10, 20, 30, 40, 50, 60, 70 and >70 after ovulation (n = 4/group) were used for ex vivo experiments. Pro-apoptotic proteins expression (CASPASES, 3, 8, 9 e BAX) were analyzed by immunohistochemistry and western blotting, and the gene expression of CASP3, 8, 9, BAX, FAS, MKI67, ESR1 and ESR2 were analyzed by real-time PCR. In the second step of this study, CL from 12 bitches on days 20, 40 and 60 (n = 4 per group) were used. Luteal cells were isolated and divided into six treatments: Control, E2 (treated with E2), ERα Blocker (treated with MPP), ERβ Blocker (treated with PHTPP), ERα + E2 Blocker (treated with E2 + MPP) and E2 + ERβ Blocker (treated with E2 + PHTPP). The expression of the same genes from the in vivo experiment was evaluated, as well as that of CYP19A1, CYP11A1, HSD3B1 and SLC2A4. In general, the expression of pro-apoptotic factors was higher from day 40 and reached highest expression on days 60 and 70 after ovulation, coinciding with increasing in expression of ERS2. This correlation was also observed in the cells from the group E2 + ERα blockade, which also showed HSD3B1down-regulation. When ERβ was blocked, cells of days 20 and 40 post ovulation responded increasing the expression of steroidogenesis and proliferation related genes. Thus, we deduce that the ERα blockade promotes the increase of pro-apoptotic and that o ERβ of luteotrophic genes expression. Our findings confirm the pleiotropic role of estradiol in canine CL and include this hormone, as well as the balance between its two receptors, among the factors controlling canine CL lifespan. (AU) | |
| FAPESP's process: | 12/17367-1 - The role of 17b-estradiol in the luteolytic process of non-pregnant bitches |
| Grantee: | Antenor Pereira Bonfim Neto |
| Support Opportunities: | Scholarships in Brazil - Master |