Dynamics of angiogenic factors in corpora lutea of pregnant and pseudopregnant bitches

Author(s)

Anderson Alves Ribeiro

• Document type: Master's Dissertation
• Press: Botucatu. 2018-11-28.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Medicina Veterinária e Zootecnia. Botucatu
• Defense date: 2018-11-20
• Advisor: Maria Denise Lopes

Abstract

The objective of this study is to obtain a deeper understanding of regulatory mechanisms of maintenance and especially of the end of the luteal function in pregnant and non-pregnant bitches. The profile of P4 is very similar in pregnant and non-pregnant bitches, but it begins to diverge approximately on day 60 of the luteal phase. At this moment, an abrupt decline of P4 is evidenced in the pregnant bitches, signaling the prepartum luteolysis: associated to an increase of the PGF2α and great apoptotic activity inside the corpus luteum (CL). Differently from non-pregnant bitches, where luteal regression is passive and preprogrammed. In the present work, it was validated the expression of the main angiogenic factors - VEGFA, IGFBP5, Endothelin, THBS2 and TGFB1 in CLs of cyclic and pregnant bitches. For this, the estral cycle of females in cyclic diestrus (n = 20) was monitored and the females of the pregnant group were artificially inseminated (n = 20). All females were submitted to ovariohysterectomy (OSH) on days 10, 20, 40 and 60 after the preovulatory LH surge. The collected CLs were submitted to qRT-PCR and immunofluorescence techniques. For statistical analysis, the student's t-test was applied, the data analyzed by the program GraphPadPrism 6 and it was considered significant when p <0.05. The results showed that the selected angiogenic factors were differentially expressed on days 40 and 60, especially in the group of pregnant bitches. No differences were observed in the other moments evaluated. The anti-angiogenic factors THBS2, TGFB1, VEGFA and IGFBP5 presented marked expression at the time 60 days of gestational diestrus. Endothelin was most expressed on day 60 in the group of pseudopregnants. These results reinforce the hypothesis that the mechanisms associated with luteolysis are different in pregnant and pseudopregnant (AU)

• FAPESP's process: 16/15767-3 - Characterization of angiogenic factors present in corpora lutea of pregnant and non-pregnant dogs
• Grantee: Anderson Alves Ribeiro
• Support Opportunities: Scholarships in Brazil - Master