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UBC Theses and Dissertations

The effect of expression of estrus at artificial insemination on target genes in the endometrium, conceptus and corpus luteum of beef cows Davoodi, Saeideh


The aim of this study was to test the effect of expression of estrus at artificial insemination (AI) on the endometrium, conceptus and corpus luteum (CL) gene expression. Twenty-three multiparous non-lactating Nelore cows were enrolled on an estradiol (E2) and progesterone (P4) based timed-AI protocol (AI = d 0), then slaughtered for endometrium, CL and conceptus collection on d 19. Body condition score (BCS), blood samples and ultrasound examination was performed on d 0, 7 and 18 of the experiment followed by RNA extraction and quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis of 58 target genes. Data was checked for normality and analysed by ANOVA for repeated measures using proc GLM, MIXED and UNIVARIATE. Estrous expression had no correlation with parameters such as BCS, pre-ovulatory follicle and CL diameter, P4 concentration in plasma on d 7 and 18 after AI and IFN-tau concentration in the uterine flushing (P > 0.05); however, a significant increase was observed in conceptus size (P = 0.02; 38.3 ± 2.8 vs 28.2 ± 2.9). The majority of transcripts affected by estrous expression in the endometrium belong to the immune system and adhesion molecule family (MX1, MX2, MYL12A, MMP19, CXCL10, IGLL1 and SLPI) (P ≤ 0.05). Genes related to apoptosis, P4 synthesis and prostaglandin receptor were down-regulated (CYP11A, BAX and PGF2α receptor) (P < 0.05) in the CL tissue of cows in estrus. In addition, four genes were identified as differentially expressed in the 19 old conceptus from cows observed in estrous (ISG15, PLAU, BMP15 and EEF1A1; P<0.05). There was also a significant effect of P4/d7 mainly affecting immune system, adhesion molecules and wnt signaling pathway of endometrium (IGLL1, MX2, SLPI, TRD, APC, WNT2, GLYCAM1 and MYL12A) (P<0.05). A significant interaction between estrus expression and P4 concentration on d 7 was more pronounced in immune system genes (MX1, MX2, TRD, SLPI and IGLL1; P<0.05). This study demonstrated that estrous expression at the time of AI, in spite of ovulation being induced by E2, could alter the gene expression profile in reproductive tissues during the pre-implantation phase.

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