Progesterone dose during synchronization treatment alters luteinizing hormone receptor and steroidogenic enzyme mRNA abundances in granulosa cells of Nellore heifers

The objective was to investigate effects of progesterone (P₄) dose on abundance of luteinizing hormone receptor (LHCGR), aromatase (CYP19A1), 3β-hydroxysteroid dehydrogenase (HSD3B1), and other steroidogenic mRNA transcripts in granulosa cells from dominant follicles. Nellore heifers were assigned to one of six groups: new, first-use controlled internal drug release device (CIDR1) inserted for 5 days (Large-P₄-dose-D5; n = 7) or 6 days (Large-P₄-dose-D6; n = 8), prostaglandin (PG)F_2α administered on D0 and 1 previously-used CIDR (CIDR3) inserted for 5 days (Small- P₄-dose-D5; n = 8) or 6 days (Small-P₄-dose-D6; n = 8), CIDR1 inserted on D0 and removed plus PGF_2α on D5 (Large-P₄-dose-proestrus (PE); n = 7), and CIDR3 and PGF_2α on D0 and 1, CIDR3 removed plus PGF_2α on D5 (Small-P₄-dose-PE; n = 7). Duration of P₄ treatment (D5 compared to D6) affected abundances of CYP19A1 mRNA transcripts, with there being greater abundances on D6 than D5 (P ≤ 0.05). Heifers treated with the large dose of P₄ had a smaller dominant follicle, less serum and intra-follicular estradiol (E₂) concentrations (P ≤ 0.05) and lesser LHCGR, CYP19A1, and HSD3B1 transcript abundances (P ≤ 0.05). Heifers treated to induce PE had a larger follicle diameter (P = 0.09), greater intra-follicular E₂ concentrations and larger abundances of CYP19A1 mRNA transcript (P ≤ 0.05) than heifers of the D6 group. Overall, treatment with larger doses of P₄ resulted in lesser abundances of LHCGR, HSD3B1, and CYP19A1 mRNA transcripts; thus, potentially leading to development of smaller dominant follicles and lesser E₂ concentrations.

Molecular and cellular effects of insulin-like growth factor-1 and LongR3-IGF-1 on in vitro maturation of bovine oocytes: comparative study

Addition effects of insulin-like growth factor-1 (IGF-1) and its synthetic analogue insulin-like growth factor-1 recombinant-3 (LongR3-IGF-1) after in vitro maturation (IVM) of cattle cumulus-oocyte complexes (COCs) were compared and evaluated on meiotic progression, apoptosis and profile genes of oocyte competence (GDF9, BMP15, BAX, BCL2, OOSP1, IGFBP2, IGBFP4 and IGFBP5), and their respective cumulus cells (AREG, EGFR, FSHR, COX2, BAX, BCL2, IGFBP2, IGFBP4 and IGFBP5). The 739 COCs (n = 10 pools) of bovine ovaries were collected, selected and matured with IGF-1 (100 ng/mL), LongR3-IGF-1 (100 ng/mL), and in two control groups with 0.1% polyvinyl alcohol (PVA) or 10% fetal bovine serum (FBS), for 22-24 h. The statistical analysis was performed by a linear mixed effects model, ANOVA and Tukey tests. There was no statistical difference between experimental groups taken into account the meiotic progression and apoptosis (P > 0.05). Nevertheless, there were statistical differences (P ≤ 0.05) among FBS, IGF-1 and LongR3-IGF-1 groups for IGFBP4 gene expression, and among PVA, IGF-1 and LongR3-IGF-1 for COX2 gene expression in cumulus cells. Moreover, statistical difference was found for BCL2 gene expression between IGF-1, FBS and PVA groups and for IGFBP4 gene expression between LongR3-IGF-1, PVA and FBS in oocytes. There was no statistical difference between experimental groups for other genes evaluated. These results showed a good performance of IVM of bovine oocytes in the presence of LongR3-IGF-1 and the possibility of replacement of IGF-1 and FBS.

Partial luteolysis during early diestrus in cattle downregulates VEGFA expression and reduces large luteal cell and corpus luteum sizes and plasma progesterone concentration

Our objectives were to investigate potential changes in the size of steroidogenic large luteal cells (LLC) during partial luteolysis induced by a sub-dose of cloprostenol in early diestrus and to determine transcriptional variations in genes involved in corpus luteum (CL) functions. Cows were subjected to an Ovsynch protocol, with the time of the second GnRH treatment defined as Day 0 (D0). On D6, cows were randomly allocated into three treatments: Control (2 mL saline, im; n = 10), 2XPGF (two doses of 500 μg of cloprostenol, im, 2 h apart; n = 8) or 1/6PGF (single dose of 83.3 μg of cloprostenol, im; n = 10). Before treatments and every 8 h during the 48-h experimental period, blood samples were collected and CL volumes measured. Furthermore, two CL biopsies were obtained at 24 and 40 h post-treatment. The 1/6PGF treatment caused partial luteolysis, characterized by sudden decreases in plasma progesterone (P₄) concentrations, luteal volume and LLC size, followed by increases (to pretreatment values) in P₄ and luteal volume at 24 and 40 h post-treatment, respectively. However, at the end of the study, P4, luteal volume and LLC size were all significantly smaller than in Control cows. Temporally associated with these phenotypes, there was a lower mRNA abundance of VEGFA at 24 and 40 h, and ABCA1 at 24 h (P < 0.05). In conclusion, a sudden reduction in CL size during partial luteolysis induced by a sub-dose of PGF_2α analog on day 6 of the estrous cycle was attributed to a reduction in LLC size, although these changes did not account for the entire phenomenon. In addition to its involvement in reducing CL size, decreased VEGFA mRNA abundance impaired CL development, resulting in a smaller luteal gland and lower plasma P₄ concentrations compared to Control cows.

174 Follicular fluid extracellular vesicles obtained from Holstein cows kept under thermoneutral or heat stress conditions modify gene expression of in vitro-matured oocytes

Heat stress (HS) has a massive impact on bovine reproduction. In cows, some of these deleterious effects involve follicular development and oocyte quality. Extracellular vesicles (EV) secreted by granulosa cells play a critical role in the intrafollicular environment by directly influencing cumulus cells and oocyte functions. The objective of this study was to investigate the effect of follicular fluid EV obtained from Holstein cows kept under thermoneutral (TN) or HS conditions, on in vitro bovine oocyte maturation. Non-lactating Holstein cows were synchronized with the Ovsynch protocol and also received an intravaginal progesterone device. From ovulation day (Day 1), cows were randomly assigned to TN (26°C, 73% humidity; n=12) or HS (36°C, 70% humidity; n=12) environments. On Day 9, 2 follicles (F1 and F2) were individually aspirated and all remained follicles were ablated. Then, on Day 14, newly formed F1 and F2 were also aspirated. Follicular fluid from all follicles from each treatment was pooled and EV were obtained according to Silveira et al. (2017 PLoS One 12, 1-25) and diluted in PBS (100μL of PBS per mL of follicular fluid centrifuged). Pools of 20 cumulus-oocyte complexes (COC) grade 1 or 2 (Stojkovic et al. Biol Reprod 200164, 904-992], predominantly from Bos indicus, were submitted to the following treatment groups: Control (n=4): matured in 90μL of TCM-199 with Eagles’ salts, glutamine, NaHCO3, pyruvate, amikacin, and FSH (base medium); TN (n=4): matured in 81μL of base medium+9μL of TN EV suspension; and HS (n=4): matured in 81μL+9μL of HS EV suspension. All treatments were carried out at 38.5°C for 24h in a humid atmosphere with 5% CO2. After 24h of maturation, COC were evaluated for meiotic progression (Hoechst 33342 stain), DNA integrity (TUNEL stain), and expression of genes related to oocyte quality (TaqMan assay, Applied Biosystems/Thermo Fisher Scientific, Waltham, MA, USA). Results were analysed using ANOVA followed by Tukey post hoc test (P&lt;0.05). When the experimental groups were compared with the control group, there was no treatment effect on meiotic progression, DNA integrity, or gene expression of cumulus cells. In the oocytes of the TN group, the genes HSF1, IGFBP2, BMP15, GDF9, CDCA8, HAS2, RPL15, STAT3,and PFKP were less expressed. We concluded that oocytes matured in the presence of EV from follicular fluid of cows kept under TN conditions had lesser expression of genes related to oocyte quality. This study was supported by FAPESP (Grant #2012/18297-7) and CAPES Foundation of Brazil.

Evidence that fibroblast growth factor 10 plays a role in follicle selection in cattle

There is evidence that regulation of follicle selection in cattle involves locally produced growth factors. In the present study, we investigated the expression of members of the fibroblast growth factor (FGF) 7 family during follicle deviation. The largest and second largest follicles were recovered during the second day of a synchronised follicle wave and the future dominant and future subordinate follicles were identified based on diameter and cytochrome P450, family 19, subfamily A, polypeptide 1 (CYP19A1) mRNA levels in granulosa cells. Theca cells of the future dominant follicle contained less mRNA encoding FGF7 and FGF10 compared with those from the future subordinate follicle 2.5 days after ovulation, before a significant difference between the diameters of the future dominant and future subordinate follicles could be observed, but FGF22 mRNA levels did not change. Levels of mRNA encoding FGF receptors FGFR1B and FGFR2B in theca and granulosa cells, respectively, were lower in the future dominant follicle compared with the future subordinate follicle. Addition of FGF10 to granulosa cells in vitro significantly decreased oestradiol secretion, as well as CYP19A1, FSH receptor (FSHR) and insulin-like growth factor 1 receptor (IGF1R) mRNA abundance, whereas FGF22 had no effect. We conclude that FGF10 and FGFR2B expression is increased in the future subordinate follicle before morphological deviation, which may contribute to follicle selection.

128 Evidence that Pregnancy-Associated Serum Protein A (PAPP-A) Plays Role on Bovine In Vitro Embryo Production

The aim of present work was to assess the effects of pregnancy-associated serum protein A (PAPP-A) during oocyte in vitro maturation (IVM) on meiosis progression, DNA fragmentation, IGF-1 free bioavailability, as well as effects on embryo yield and transcriptional profile of matured cumulus–oocyte complexes (COC). First, the COC from a local abattoir were submitted to IVM for 24 h with TCM-199 serum-free medium supplemented with PAPP-A (100 ng mL−1: P100 group) or not (control group). The matured oocytes were submitted to evaluation of DNA fragmentation (TUNEL assay) and meiosis progression (Hoechst 33342; n = 5 replicates; 20 COC/replicate per group), and maturation medium was collected to measure levels of free IGF-1. Then, the oocytes were separated from their respective cumulus cells and followed for the transcriptional profile of 96 genes (3 reference genes; ACTH, GAPDH, PPIA) by RT-qPCR using Taqman® assays in the HD-Biomark System® (Fluidigm Corp., South San Francisco, CA, USA). Further, the matured oocytes were submitted to in vitro fertilization followed by in vitro culture for 7 days. On Days 3 and 7, the cleavage and blastocyst (BL) rates were verified. On Day 7, BL (3 BL/pool; control: n = 4 pools; P100: n = 5 pools) were collected to analyse the transcriptional pattern of 96 genes (4 reference genes; ACTH, GAPDH, PPIA, and SDHA) as described above for COC. The DNA fragmentation, meiosis progression, cleavage, and BL rates were calculated as percentages and transformed to arcsine. The mRNA abundance of target genes was normalized by geometric mean of reference genes and data were transformed to fold change. The free IGF-I concentration also was transformed to fold change. All data were tested by ANOVA and means were compared with t-test or Wilcoxon tests using JMP software (SAS Institute Inc., Cary, NC, USA). Differences were considered significant when P ≤ 0.05. The addition of PAPP-A increased free IGF-I concentration 1.27-fold in IVM medium. There were no alterations in the percentage of oocytes in metaphase II or oocyte DNA fragmentation. In cumulus cells, the genes BCL2, GPX1, RPLP0, and RPS25 (anti-apoptotic and anti-oxidative stress) was higher in the P100 group, whereas DICER, GREM1, GUCY1B3, and FOXO3 (cell proliferation, cumulus expansion, cGMP regulator, and apoptotic initiator, respectively) were higher in the control group. In oocytes, the mRNA relative abundance of ACACA, BCL2, H1FOO, TXNRD1, and VCAN (related with fatty acid synthesis, anti-apoptotic effect, chromatin regulation, oxidative stress processes, and cell proliferation, respectively) was higher in the P100 group. There was no difference in cleavage rate or embryo yield. The mRNA abundance of genes related to cellular stress (ATF4, GPX4, and HIF1A) and lipid metabolism (FASN and SREBF1) was lower in embryos of the P100 group. On the other hand, genes involved in cellular proliferation/differentiation (MAPK1) and pluripotency (POU5F1) were up-regulated in embryos of the P100 group. In conclusion, the addition of PAPP-A during the IVM increased free IGF-I and modulates the gene expression in COC and blastocysts, which could modify oocyte competence and embryo development.

183 GENE EXPRESSION OF IN VITRO-MATURATED OOCYTES CAN BE MODULATED BY FOLLICLE EXOSOMES FROM COWS KEPT UNDER THERMONEUTRAL OR HEAT STRESS CONDITIONS

There are several intrafollicular agents that have the ability to interfere with the metabolism and development of the oocyte, among these we highlight the exosomes (EXO). Thus, the aim of this study was to evaluate the capacity of EXO extracted from the follicular fluid of cows kept under thermoneutral or heat stress conditions to modulate oocyte maturation in vitro. Twenty-four Holstein cows were subjected to the following treatments for 14 days: heat stress (HS; n = 12), 38°C, 60% RH, temperature-humidity index = 88; and thermo-neutral (TN; n = 12), 24°C, 60% RH, temperature-humidity index = 71. Cows had their follicles aspirated when their diameter reached 9 to 12 mm; all follicles with this diameter were aspirated. All follicular fluid aspirated from cows subjected to HS or TN was pooled forming the groups (HS and TN). The EXO were obtained by ultracentrifugation of follicular fluid (120,000 × g for 70 min at 4°C, twice) and had their presence confirmed by transmission electron microscopy. Bos indicus cumulus-oocyte complexes (COC) collected from ovaries obtained in commercial slaughterhouse, were pooled in groups of 20 COC and randomly subjected to 1 of the following treatments: Control, matured in standard medium (TCM 199, supplemented with Earle’s salts, glutamine, NaHCO3, pyruvate, FSH, and amikacin); HS-EXO, matured in standard medium added with 10 µL of a solution of follicular EXO from HS cows; and TN-EXO, matured in standard medium added with 10 µL of a solution of follicular EXO from TN cows. The procedures were repeated 4 times, always with 20 COC per treatment in each replica. After 22 h of maturation, COC were recovered and the expression of genes related to apoptosis protection (BCL2), cell viability (STAT3), cell maintenance (RPL15), oocyte competence (BMP15), oxidative stress (CPT1B), cumulus cell expansion (HAS2), cell cycle (CDCA8), and heat stress protection (HSF1) were assessed. Oocyte genes were differentially expressed according to the source of EXO. Groups were statistically analysed using ANOVA and Tukey tests. All genes, except CPT1B, showed lower expression in TN-EXO oocytes when compared with control and HS-EXO (P < 0.05). CPT1B showed a higher expression in HS-EXO oocytes (P < 0.05). The results showed that the addition of EXO from exogenous follicles can modulate the expression of oocytes genes related to cell viability and survival. The lower expression of these genes in TN-EXO suggested that the EXO obtained in TN conditions attenuate several genes related to the oocytes maturation and viability. Surprisingly, the control oocytes showed a similar gene expression pattern of the HS-EXO. In conclusion, EXO derived from follicular fluid of cows submitted to TN or HS conditions can modulate the gene expression of oocytes matured in vitro. These results open new perspectives for the use of theses EXO as a tool to increase the efficiency of in vitro oocyte maturation. Financial support from FAPESP #12/18297–7.

Gene expression profile in heat-shocked Holstein and Nelore oocytes and cumulus cells

The present study determined the transcriptome profile in Nelore and Holstein oocytes subjected to heat shock during IVM and the mRNA abundance of selected candidate genes in Nelore and Holstein heat-shocked oocytes and cumulus cells (CC). Holstein and Nelore cows were subjected to in vivo follicle aspiration. Cumulus–oocyte complexes were assigned to control (38.5°C, 22 h) or heat shock (41°C for 12 h, followed by 38.5°C for 10 h) treatment during IVM. Denuded oocytes were subjected to bovine microarray analysis. Transcriptome analysis demonstrated 127, nine and six genes were differentially expressed between breed, temperature and the breed × temperature interaction respectively. Selected differentially expressed genes were evaluated by real-time polymerase chain reaction in oocytes and respective CC. The molecular motor kinesin family member 3A (KIF3A) was upregulated in Holstein oocytes, whereas the pro-apoptotic gene death-associated protein (DAP) and the membrane trafficking gene DENN/MADD domain containing 3 (DENND3) were downregulated in Holstein oocytes. Nelore CC showed increased transcript abundance for tight junction claudin 11 (CLDN11), whereas Holstein CC showed increased transcript abundance for antioxidant metallothionein 1E (MT1E) . Moreover, heat shock downregulated antioxidant MT1E mRNA expression in CC. In conclusion, oocyte transcriptome analysis indicated a strong difference between breeds involving organisation and cell death. In CC, both breed and temperature affected mRNA abundance, involving cellular organisation and oxidative stress.

182 EFFECTS OF IGF-1 OR IGF-1-LongR3 ON CELLULAR AND MOLECULAR ASPECTS OF CUMULUS-OOCYTE COMPLEXES DURING IN VITRO OOCYTE MATURATION IN CATTLE

The insulin-like growth factor-1 recombinant -3 (IGF-1-LongR3), a synthetic analogue of IGF-1 with increased bioavailability has not yet been used in vitro maturation (IVM) medium of bovine oocytes. Therefore, the aim of this study was to evaluate and compare the addition effects of IGF-1-LongR3 or IGF-1 in IVM bovine oocytes on meiotic progression, apoptosis, and profile of oocytes genes (GDF9, BMP15, BAX, BCL2, OOSP1, IGFBP2, IGFBP4 and IGFBP5) and genes in cumulus cells (AREG, EGFR, FSHR, COX2, BAX, BCL2, IGFBP2, IGFBP4 and IGFBP5). Bovine ovaries were collected in slaughterhouses, and 739 oocytes with grades 1 or 2 were selected after aspiration of 2- to 8-mm follicles. IVM was carried out in TCM199 with FSH, LH, and antibiotics (BM) supplemented with 100 ng mL–1 IGF-1 or 100 ng mL–1 LongR3-IGF-1. Control oocytes were matured in BM supplemented with 0.1% polyvinyl alcohol (PVA) or 10% FCS. For all groups, maturation was performed during 22–24 h in an incubator at 38.5°C and 5% CO2 in air. Subsequently oocytes were denuded and analysed for apoptosis, nuclear maturation, and gene expression by TUNEL assay, staining Hoechst 33342, and RT-qPCR, respectively. Statistical analysis was performed using a linear mixed effects model, which correlated the change in metaphase stage 1 to 2 and the absence of apoptosis among the experimental groups. ANOVA and Tukey tests were used to analyse the results obtained by RT-qPCR. After 10 replicates of IVM, 339 oocytes were evaluated for meiotic progression and apoptosis and 400 oocytes for gene expression. There was no statistical difference between the experimental groups with respect to meiotic progression and apoptosis. BCL2 and IGFBP4 gene were less expressed in oocytes matured with IGF-1 and LongR3-IGF-1 compared with control groups. GFBP4 was also less expressed in cumulus cell of oocytes from the experimental groups. Moreover COX2 expression was statistically elevated in cumulus cells matured in the presence of IGF-1 and LongR3-IGF-1 It was possible to perform IVM of bovine oocytes in the presence of LongR3-IGF-1, allowing its use in replacement of IGF-1 and FCS. The results of this study will provide more information on the interaction of IGF with the IGFBP and its importance for oocyte maturation.

205 SITE OF OVULATION ALTERS GENE PROFILE IN THE OVIDUCT FROM NELORE (BOS TAURUS INDICUS) AND ANGUS HEIFERS (BOS TAURUS TAURUS)

The oviduct plays a key role promoting a favourable microenvironment to gametes transport, fertilization and early embryo development. Numerous differences in reproductive physiology are known among animals of Zebu and European breeds. Reports indicate that female Zebu cattle have a higher number of follicles per wave than female European cattle and individual distinctions in the number of follicles recruited are present in both breeds, namely animals with high follicular count (HFC) and low follicular count (LFC). Furthermore, the follicular count is related to animal fertility and is greatly influenced by the activity of FSH, oestradiol, and androgens. However, little is known about the effects of follicular count differences between Zebu and European cattle, and between breeds in the oviduct molecular profile. Based in these information, we hypothesised that differences in bovine breed (Nelore and Aberdeen Angus), differences in the follicular count (FC), and differences in the antimere related to ovulation (ipsilateral and contralateral) alter the molecular profile of genes involved in oviducal functions during the initial period after ovulation. To do so, oviducts from Nelore heifers (HFC, n = 4; LFC, n = 4) and oviducts from Aberdeen Angus heifers (HFC, n = 4; LFC, n = 4) were isolated and oviducal segments were divided (infundibulum, ampulla, isthmus) from ipsilateral and contralateral antimere. Total RNA was extracted using Illustra TriplePrep Kit (GE Healthcare, Waukesha, WI, USA) and then reverse transcription was performed using a high-capacity cDNA kit (Life Technologies, Carlsbad, CA, USA), according to the manufacturer's protocols. Relative RT-qPCR analysis was performed with TaqMan® Low Density Array (TLDA, Life Technologies). The mRNA abundance of the target was tested by ANOVA analysis, using PROC GLM procedure of SAS (SAS, 9.2, SAS Institute Inc., Cary, NC, USA). Individual differences were analysed through pair-wise comparisons (SAS). All the comparisons were performed in each segment (ampulla, infundibulum, and isthmus); no comparisons were performed between segments. The differences were considered significant when P < 0.05. In the ampulla, the mRNA abundance of COX2, OVGP1, GPR78, FUCA1, and ANXA4 showed higher levels in ipsilateral antimere compared to contralateral. Similarly, in the infundibulum the mRNA abundance of GRP78, PGTER4, FUCA2, and FUCA1 was higher in ipsilateral antimere. No difference was found in the isthmus. In conclusion, the breed and the follicular count have no effect on the molecular profile of bovine oviduct, suggesting the site of ovulation has the main effect in gene expression related to gametes transport, fertilization, and early embryo development.Research supported by FAPESP 2012/09498-9 and 2012/50514-8.

Expression of fibroblast growth factor 10 and cognate receptors in the developing bovine ovary

In the mammalian ovary, FGF10 is expressed in oocytes and theca cells and is a candidate for paracrine signaling to the developing granulosa cells. To gain insight into the participation of FGF10 in the regulation of fetal folliculogenesis, we assessed mRNA expression patterns of FGF10 and its receptors, FGFR1B and FGFR2B, in relation to fetal follicle dynamics and localized FGF10 protein in bovine fetal ovaries at different ages. Primordial, primary, secondary, and antral follicles were first observed on Days 75, 90, 150, and 210 of gestation, respectively. The levels of GDF9 and BMP15 mRNA, markers for primordial and primary follicles, respectively, increased during fetal ovary development in a consistent manner with fetal follicle dynamics. CYP17A1 mRNA abundance increased from Day 60 to Day 75 and then from Day 120 to Day 150, coinciding with the appearance of secondary follicles. FGF10 mRNA abundance increased from Day 90, and this increase was temporally associated with increases in FGFR1B mRNA abundance and in the population of primary follicles. In contrast, FGFR2B mRNA expression was highest on Day 60 and decreased thereafter. FGF10 protein was localized to oogonia and oocytes and surrounding granulosa cells at all fetal ages. The present data suggest a role for FGF10 in the control of fetal folliculogenesis in cattle.

209 EXPRESSION OF GENES RELATED TO OVULATORY CAPACITY (LHR AND AGTR2) IN GRANULOSA CELLS FROM SUPERSTIMULATED OR NOT SUPERSTIMULATED ANGUS COWS

Multiple ovulation and embryo transfer (MOET) has contributed to genetic improvement of Brazilian cattle and the P36 superstimulatory treatment protocol has been used successfully in MOET programs. Recently, increased mRNA levels of LH receptor (LHR) and angiotensin II receptor type 2 (AGTR2) have been reported in granulosa cells (GC) of superstimulated Nelore cows using P36 protocol and the efficacy of the P36 protocol has been investigated with the addition of a LH stimulus (eCG or LH), on the last day of treatment. We aimed to evaluate mRNA abundance of AGTR2 and LHR, related to ovulatory capacity, in GC of superstimulated Angus cows by different variations of the P36 protocol. Multiparous Angus cows (n = 37) were randomly assigned to four groups: control, P36, P36+eCG, and P36/FSH+LH. The control group (non-superstimulated cows, n = 7) received an intravaginal device containing progesterone (1.0 g; Primer®; Agener Animal Health, São Paulo, SP, Brazil) and 2.5 mg of oestradiol benzoate (EB; RIC-BE®; Agener Animal Health; IM) on a random day of the oestrous cycle (Day 0). After 8 days (Day 8) cows were treated with PGF2α (150 mg d-cloprostenol; Prolise®; Agener Animal Health; IM; 7:00 a.m.) and the intravaginal device was removed (7:00 p.m.). Cows from P36 group (n = 10) received the intravaginal device and 2.5 mg of EB at the beginning of the protocol (Day 0). Starting 5 days later (Day 5), 200 mg pFSH (Folltropin®; Bioniche Animal Health, Belleville, ON, Canada) was administered twice daily by IM injections over 4 days; on Day 7, PGF2α was administered and the intravaginal device was removed 36 h later (Day 8, 7:00 p.m.). Groups with the addition of a LH stimulus (eCG or LH administration) were submitted to the P36 protocol with replacement of the last two FSH doses by 200 IU eCG (P36+eCG; Novormon®, MSD Animal Health, São Paulo, SP, Brazil, IM; n = 10) or 2 mg pLH concomitant with the last two doses of FSH (P36/FSH+LH; Lutropin®, Bioniche Animal Health, IM; n = 10). Cows in all groups were slaughtered on Day 9, 12 h after progesterone-device removal and ovaries were transported on ice to the laboratory immediately after slaughter. Non-superstimulated dominant follicles and superstimulated follicles were dissected from the ovaries to obtain GC and total RNA was extracted. Amplification of housekeeping (peptidyl-prolyl isomerase A; PPIA) and target genes was performed by real-time RT–PCR according to the Sybr Green protocol. Relative gene expression was determined by Pfaffl's equation. The mRNA abundance was compared by Tukey's test and the significance level was P < 0.05. In GC, the mRNA abundance (mean ± s.e.m.) of LHR and AGTR2 was higher in the control group (1.02 ± 0.24 and 3.76 ± 1.07, respectively; P < 0.05) when compared with the superstimulated groups: P36 (0.33 ± 0.24 and 1.02 ± 0.21), P36+eCG (0.42 ± 0.10 and 1.40 ± 0.33) and P36/FSH+LH (0.38 ± 0.07 and 1.45 ± 0.49). In conclusion, the superstimulatory treatments decrease mRNA levels of LHR and AGTR2. We acknowledge CAPES for E. Lucacin's scholarship and FAPESP–São Paulo Research Foundation for grant number 2011/50593-2.

214 EFFECT OF OVARIAN SUPERSTIMULATION ON EXPRESSION OF GENES ASSOCIATED WITH THE OOCYTE DEVELOPMENTAL COMPETENCE OF NELORE COWS

The P36 protocol has contributed to the genetic improvement of Brazilian herd through its successful use in embryo transfer programs. We aimed to investigate the effect of P36 protocol on embryo yield and mRNA expression of genes correlated with the competence of cumulus–oocyte complex (COC): receptors of FSH (FSHR), EGF (EGFR), and pentraxin 3 (PTX3) in cumulus cells; receptors of LH (LHR) and angiotensin 2 (AT2) in granulosa cells; and GDF9, BMP15, and histone H2A (H2A) in oocytes. Multiparous Nelore cows were allocated in control and P36 groups. Control group (non-superovulated, n = 15) received a progesterone intravaginal device (P4, 1.0 g, Primer®, Tecnopec, Sao Paulo, Brazil) and 2.5 mg of oestradiol benzoate (EB, IM, BER-BE®, Syntex, Buenos Aires, Argentina) at a random day of the oestrous cycle (Day 0). A PGF2α analogue (150 mg d-cloprostenol, IM, Prolise®, RARS SRL) was administered (Day 8) and Primer® was removed. The P36 group (n = 10) received a Primer® and 2.0 mg of EB (Day 0). The FSH treatment (160 mg Folltropin®, Bioniche Animal Health, Ontario, Canada) was initiated at decreasing doses: 40, 30, 20, and 10% of the total dose twice daily for 4 days (Day 5). The PGF2α analogue was administered (Day 8) and after 36 h primer was removed. Animal slaughter to ovary collection was performed 12 h after Primer® removal (Day 9). Some of the oocytes were matured (TCM199), fertilized with Nelore semen (n = 6), and cultured (SOF-synthetic oviduct fluid) to the blastocyst stage. Embryos were removed from culture (Day 6), allocated in 5 pools with 5 embryos in each group, and subjected to RNA extraction. Remaining oocytes were denuded from cumulus and zona pellucida (vortex and Protease®, Sigma-Aldrich, St. Louis, MO, USA). Pools of 20 oocytes and of their respective cumulus cells (n = 6 pools; control group and n = 4 pools, P36 group) were subjected to RNA extraction (RNeasy kit, Qiagen, Valencia, CA, USA). Gene expression was performed by real-time RT-PCR using oligo-dT in reverse transcription and bovine-specific primers. Expression of cyclophilin A was used as endogenous control. Change to developmental rates to the blastocyst stage and transcript abundance were compared by t-test and significance was considered when P < 0.05. Blastocyst rates were also similar (P > 0.05) in groups P36 (40/99; 40%) and control (16/43; 37%). Expression of H2A, EGFR, FSHR, and PTX3 in cumulus cells did not differ (P > 0.05) among treatment groups. The expression of GDF9 and BMP15 in cumulus cells was higher (P < 0.05) in the P36 group, but in oocytes these transcripts were more expressed in the control group (P < 0.05). Although important genes (GDF9 and BMP15) were less expressed in oocytes from superstimulated cows, the maintenance of H2A in oocytes, as well as PTX3, EGFR, and FSHR, and the increases in GDF9 and BMP15 expression in cumulus cells do not seem to affect oocyte competence due to the similar embryo yield of both groups. Supported by FAPESP.

175 THE EFFECT OF NUTRITION ON OVARIAN FOLLICLE POPULATION AND PLASMA ANTI-MULLERIAN HORMONE CONCENTRATION IN ABERDEEN ANGUS HEIFERS

The number of follicles in ovaries from cows is highly variable and has a high repeatability in females during the follicular waves. There is evidence that dietary restriction during pregnancy has a deleterious effect on fetal ovary reserve (Mossa et al. 2009). The anti-Mullerian hormone (AMH) is a member of the TGFβ superfamily, produced by granulosa cells from healthy growing follicles, and its concentration is correlated with the number of follicles recruited in the wave during the oestrous cycle and may be used as a biomarker of the follicle population in cattle. Our objective was to compare the number of follicles and AMH concentration in heifers born from cows that suffered food restriction during the first trimester of pregnancy (March to May of 2009) to heifers born from cows that did not suffer food restriction (March to May of 2010) in Bagé, RS, Brazil. Because the diet of these cows were pasture based when rain dropped from an average of 129 mm3 (from 2002 to 2008) to 64 mm3 (in 2009), these cows suffered food restriction. In 2010 rain averaged 83 mm3, reestablishing normal feeding conditions. Ovarian follicle count analysis and blood drawing was performed in 89 heifers born in 2009 and 131 heifers born in 2010. The counting of antral follicles (>3 mm) by ultrasound was only in heifers with absence of follicles >6 mm at the time of assessment. Cows from both years were also grouped into low (LFC) or high (HFC) follicle count. Plasma AMH concentrations (pg mL–1) were determined by ELISA using human AMH/MIS Gen II commercial kit (Beckman Coulter, Brea, CA, USA) validated using plasma from cows of HFC and LFC, a castrated bull, and a pool of follicular fluid. Results were analysed using the Proc GLM procedure of SAS (SAS 9.2). Follicle LSmean was higher (P < 0.05) in heifers that did not suffer food restriction (19.09 ± 0.8) when compared with heifers born from cows that suffered food restriction (11.75 ± 0.75). Within no food restriction and food restriction groups, LFC heifers averaged 10.91 ± 1.21 and 4.16 ± 1.02 follicles, respectively, and HFC heifers averaged 27.28 ± 1.0 and 19.35 ± 1.0 follicles, respectively. Anti-Mullerian hormone concentration was higher (P < 0.05) for heifers born in 2010 (no food restriction; 77.24 ± 4.71 pg mL–1) when compared with heifers born in 2009 that mothers suffered food restriction (30.89 ± 4.32 pg mL–1). Furthermore, within heifers from the food restriction group AMH concentration was higher (P < 0.05) in HFC heifers (47.17 ± 6.2) when compared with LFC heifers (14.61 ± 6.0). However, there was no difference in AMH concentration between LFC and HFC in the no-food restriction group. In conclusion, dietary restriction during the first trimester of pregnancy might result in reduced follicle population in the female offspring; however, caution should be taken since animal variation is consistent. Furthermore, AMH concentration can be used as a biomarker for follicle population. This research and scholarship for Ereno, Pupulim, Loureiro, Favoureto, and Castilho is from FAPESP.

198 PROGESTERONE, ESTROGEN (ER-α AND ER-β), AND OXYTOCIN RECEPTOR GENE EXPRESSION IN CANINE EMBRYOS

The aim of this study was to compare the mRNA levels of hormone receptor for progesterone (PR), oestrogen α (ER-α), oestrogen β (ER-β), and oxytocin (OTR) in canine morulae and blastocysts. Ten healthy mature bitches were inseminated based on monitoring vaginal cytology and progesterone concentration. The first insemination was performed on Day 2 after the preovulatory LH surge (progesterone 4 ng mL–1), and the second was performed 48 h later. All females were submitted to ovariohysterectomy (OVH), and the oviduct as well the uterurs were flushed with PBS solution to obtain the embryos. The females were divided into two groups: Group A (n = 5), morulae were collected 8 days after the LH surge and Group B (n = 5), blastocysts were collected 12 days after the LH surge. The pools (n = 10) of embryos (5 embryos/pool) were stored in RNAlater® (Ambion, Life Technologies, USA) at –80°C. The samples were analysed together. The RNA later was removed used PBS calcium free and the total RNA extraction was performed using the Qiagen RNeasy micro-kit (Hildesheim, Germany). Before reverse-transcription (RT) reaction, the total RNA was treated with DNase I Amplification Grade (Invitrogen Life Technologies, Carlsbad, CA, USA). The gene expression of target genes was assessed by real-time RT-qPCR, using SuperScript III for RT and power SYBR Green PCR Master Mix (Applied Biosystems, USA) for cDNA for PCR. The primers for target genes were designed using the software Primer Express® (Applied Biosystems, USA). The gene expression of target genes was normalized by HPRT gene and the relative abundance of mRNA was determined by the ΔΔct method corrected by amplification efficiency using Pffafl’s equation. The means of mRNA relative abundance were compared by t-test. The PR mRNA expression only in blastocysts is similar to the results obtained by Hou et al. (1997) in rat embryos. It is believed that the absence of PR in the early stages of cleavage is due to the indirect action of progesterone by growth factors produced by the maternal reproductive tract (2). Apparently, ER-β action does not occur in the embryo canine phases analysed; however, the action of ER-α seems related to the deployment signal as seen by Hou et al. (1996) in rats. Similarly to findings in the literature, OTR expression decreased in canine embryonic development. This receptor was produced by blastocysts while present in the uterus, which may represent an incidental mechanism to the embryo control of endometrial receptivity, such as also to prevent the development of endometrial luteolytic mechanism. The variation in hormone receptors gene expression in canine embryos can be influencing the transition from morula to blastocyst. In addition, a hormonal influence on these structures can occur in different ways.

175 EFFECT OF HEAT STRESS ON GENE EXPRESSION OF IN VITRO-PRODUCED BOVINE EMBRYOS (BOS TAURUS VS. BOS INDICUS)

Heat stress (HS) reduces the production of bovine embryos, especially taurine embryos, which are not adapted to heat. However, little is known about the competence of embryos produced under HS in breeds adapted or not adapted to heat. The aim of this study was to compare the gene expression of PLAC8, HSF1, COX2 and CDX2, related to competence and implantation, in bovine in vitro-produced embryos (Bos taurus vs Bos indicus), submitted or not submitted to HS. Oocytes from Nelore (zebu) and Jersey (taurine) cows were aspirated by ovum pickup, in vitro-matured in TCM-199 medium with bicarbonate containing 10% FCS, 2 μg mL–1 of pyruvate, 75 μg mL–1 of gentamicin, 20 μg mL–1 of FSH and 10 IU mL–1 of LH for 22 h at 38.5°C in 5% CO2 in air. Matured oocytes were fertilized with semen from Nelore (n = 6) and Jersey (n = 6) bulls, respectively, at 38.5°C in 5% CO2 in air. The fertilization medium was TALP-IVF supplemented with 6 mg mL–1 of fatty acid-free BSA, 2 μL mL–1 of pyruvate, 75 μg mL–1 of gentamicin, 11 μg mL–1 of heparin and 44 μL mL–1 of penicillamine, hypotaurine and epinephrine. The day of fertilization was considered Day 0. Twelve hours post-insemination, presumptive zygotes were denuded and randomly divided into 2 groups, nonstressed or stressed and both were in vitro cultured at 38.5°C in 90% N2, 5% CO2 and 5% O2 in SOFaaci medium supplemented with 5% FCS, 5% BSA and 0,2% sodium pyruvate. In the stressed group, 96-h post-insemination embryos were subjected to HS of 41°C for 6 consecutive hours and then returned to 38.5°C. On Day 7, pools with 5 blastocysts [Nelore (n = 9); Nelore HS (n = 7); Jersey (n = 5); Jersey HS (n = 5)] were subjected to RNA extraction (RNeasy, Qiagen Inc., Valencia, CA, USA). The expression of target genes was analysed by real-time reverse transcription PCR with oligo-dT in reverse transcription and bovine specific-primers in PCR. The expression of cyclophilin A was used as an internal control. The mean mRNA levels of target genes among groups were compared by parametric ANOVA, followed by orthogonal contrast. Heat stress reduced (P < 0.05) mRNA expression of CDX2 and PLAC8 in both breeds; additionally, the expression of these genes was higher in the zebu breed when compared with the taurine breed. Messenger RNA expression of COX2 did not differ between groups, under HS or not, in both the Jersey and Nelore breeds. Moreover, HS reduced the mRNA expression of HSF1 (P < 0.05) in Nelore groups, but not in Jersey groups. The highest levels of PLAC8 and CDX2 in nonstressed Nelore embryos indicate better competence and a higher capacity of implantation of these embryos when compared with Jersey and HS embryos in both breeds. Moreover, low HSF1 levels in stressed Nelore embryos indicate the thermotolerance ability of this breed. In conclusion, the data indicate that HS alters the pattern of gene expression in Nelore and Jersey in vitro-produced bovine embryos. This research was supported by FAPESP.

180 HEAT STRESS INDUCES ALTERATION IN EXPRESSION OF GENES RELATED TO COMPETENCE AND IMPLANTATION IN NELORE BOVINE IN VITRO-PRODUCED EMBRYOS

Several factors affect early embryonic development in cattle, including heat stress. These factors can contribute to high early embryonic loss, probably altering gene expression. Studies using microarray-profiled genome-wide RNA expression for in vitro-produced blastocysts have compared embryos resulting in calf delivery or no pregnancy, and they have identified genes with potential roles in pregnancy and embryo competence. The aim of the present work was to compare the expression of some genes (PLAC8, HSF1, COX-2, and CDX-2) related to embryo competence and embryonic implantation between in vitro-produced embryos from the Nelore breed (Bos indicus), submitted or not submitted to heat stress. Oocytes from Nelore cows were aspirated by ovum pickup and matured for 22 h (TCM-199 with bicarbonate, supplemented with 10% FCS, 2 μL mL–1 of pyruvate, 75 μg mL–1 of amicacin, 20 μg mL–1 of FSH, and 2 IU mL–1 of hCG) at 38.5°C with 5% CO2 in air. The fertilization (Day 0) was performed with semen from Nellore bulls. After a 12-h fertilization period, in Tyrode’s lactate stock medium supplemented with 6 mg mL–1 of BSA, 2 mL mL–1 of pyruvate, 75 mg mL–1 of amicacin, 11 mg mL–1 of heparin, and 44 mL mL–1 of phenylalanine solution, presumptive zygotes were denuded and randomly divided in 2 groups: nonstressed and stressed. The culture medium was SOFaaci supplemented with sodium pyruvate (0, 2%), 5 mg mL–1 of BSA and 5% FCS. Embryo culture was performed at 38.5°C, 90% N2, 5% CO2, and 5% O2. In the stressed group, 96 h after fertilization, the embryos were subjected to heat stress of 41°C for 6 consecutive hours and then returned to a temperature of 38.5°C. On Day 7, pools of 5 blastocysts (nonstressed, n = 9; stressed, n = 7) were submitted to total RNA extraction (RNeasy, Qiagen, Valencia, CA). The gene expression of target genes was measured by real-time RT-PCR with oligo-dT in the reverse transcription and bovine-specific primers in the PCR. Expression of cyclophlin A was used as an internal control. The means of mRNA levels of target genes between the groups were compared by t-test. The PLAC8 mRNA levels were higher in nonstressed blastocysts in comparison with the stressed group. The HSF1 and CDX2 mRNA was detectable only in nonstressed embryos. The COX2 mRNA levels did not differ between groups. The higher levels of PLAC8 and the CDX2 expression on nonstressed embryos indicate better competence of embryos not submitted to heat stress. Furthermore, the absence of HSF1 mRNA in the stressed embryos does not reflect the lack of biological activity of this protein. In conclusion, the data indicate that heat stress alters the gene expression pattern of in vitro-produced embryos in the Nelore breed. FAPESP (São Paulo, Brazil) is acknowledged for funding and fellowships for Castilho, Satrapa, and Razza.

249 EXPRESSION OF mRNA ENCODING EPIDERMAL GROWTH FACTOR-LIKE FACTORS IN BOVINE CUMULUS CELLS DURING IN VITRO MATURATION: EFFECTS OF TIME AND FOLLICLE-STIMULATING HORMONE

Epidermal growth factor (EGF)-like family members [amphiregulin (AREG), epiregulin (EREG), and betacellulin (BTC)] have been shown to be important regulators of cumulus–oocyte complex (COC) maturation, particularly cumulus expansion. The aim of this study was to determine the temporal expression patterns of mRNA encoding EGF-like growth factors in bovine cumulus cells (CC) during COC in vitro maturation and to assess the effects of grading doses of FSH on EGF-like mRNA expression in CC. Immature COC (grades 1 and 2) were obtained from 2- to 8-mm follicles from abattoir ovaries. In the first experiment, CC were separated from 20 COC and frozen before (immature group) or after COC culture for 4, 8, 12, 16, and 20 h with (10 ng mL–1) or without FSH. In the second experiment, pools containing 20 COC were matured for 12 h with grading doses of FSH (0, 0.1, 1, 10, and 100 ng mL–1). After culture, CC were mechanically separated and stored at –80°C. Total RNA was extracted using RNeasy® (Qiagen, Valencia, CA, USA), and 100 ng of RNA was reverse transcribed. Expression of target genes was assessed by real-time PCR and normalized by Cyclophilin (CYC-A). Relative quantification of mRNA abundance was determined by the Pfaffl equation. Effects of time of culture and FSH treatment were tested by ANOVA, and groups were compared by Tukey-Kramer honestly significant difference test. Nonparametric analysis was used when data were not normally distributed. Differences were considered significant when P < 0.05. In the presence of FSH, AREG and EREG mRNA abundance was increased at 4 h of culture, whereas in the absence of FSH, AREG but not EREG mRNA levels were increased by 4 h of culture. The addition of FSH stimulated AREG mRNA expression from 4 to 16 h of culture. In contrast, BTC mRNA was more expressed in immature CC, decreased after 4 h of culture with FSH, and did not vary during maturation in the absence of FSH. In the dose–response experiment, AREG and EREG mRNA expression was stimulated by FSH starting from 10 ng mL–1 and did not increase from 10 ng mL–1 to 100 ng mL–1. Again in contrast, BTC mRNA expression was inhibited by FSH at 100 ng mL–1. In conclusion, the present data suggest that FSH differently regulates the expression of EGF-like factors during bovine COC maturation, although AREG and EREG are stimulated, BTC is inhibited by FSH. This work was supported by FAPESP.

249 PROFILE OF MEMBERS OF IGF SYSTEM GENE EXPRESSION IN BOVINE IMMATURE OOCYTES: COMPARISON BETWEEN NELLORE (BOS INDICUS) AND HOLSTEIN (BOS TAURUS)

There is evidence that IGF system can be involved in the oocyte competence and, consequently, in the embryo development. To better understand possible differences between Bos taurus and Bos indicus in in vitro embryo development, the current work aimed to assess the expression of IGF ligands (IGF-1 and 2), types 1 and 2 IGF receptors (IGFR1 and 2), IGF-binding proteins 2 and 4 (IGFBP-2 and 4), and type A pregnancy-associated plasmatic protein (PAPP-A) mRNA in bovine immature oocytes fromBos Taurus and Bos indicus. Nellore and Holstein cows were submitted to ovum pickup, and the oocytes with grade 1, 2, and 3 were selected. To remove cumulus cells and pellucida zone, respectively, the oocytes were submitted to vortex (900 × g for 3 min) and protease treatment (Protease® from Streptomyces griseus, Sigma-Aldrich Corporation, St. Louis, MO, USA). Pools of 20 oocytes obtained from Nellore (n = 8) and Holstein (n = 4) cows were submitted to total RNA extraction (RNeasy, Qiagen, Valencia, CA, USA). The gene expression of target genes was measured by real-time RT-PCR with oligo-dT in the RT and bovine-specific primers in the PCR. Expression of cyclophlin A (CYC-A) was used as internal control. The means of mRNA levels of target genes between the breeds were compared using t-test and Mann-Whitney test when the data had normal or not normal distribution, respectively. The means values of mRNA expression of IGF-1, IGF-2, IGF receptors (1 and 2), and IGFBP 2 and 4 were greater in Holstein (0.96 ± 0.21, 0.74 ± 0.27, 1.08 ± 0.04, 1.19 ± 0.5, 1.21 ± 0.23, 0.53 ± 0.15, respectively) compared with Nellore (0.48 ± 0.10, 0.07 ± 0.02, 0.04 ± 0.03, 0.06 ± 0.02, 0.05 ± 0.01, 0.03 ± 0.15, respectively; P < 0.01). Never- theless, mRNA expression of PAPP-A was much greater in Nellore (28.10 ± 18.96) than in Holstein (1.32 ± 0.17; P < 0.05). These results suggest that high expression of PAPP-A and low expression of IGFBP-2 and 4 could allow more efficiency on the degradation of IGFBP and increase the IGF bioavailability in the oocytes from Nellore as compared with Holstein cows. Satrapa, Simões, and Castilho received a fellowship and funding from FAPESP (São Paulo, Brazil).

225 FOLLICULAR DIAMETER, OVULATION RATE, AND LH RECEPTOR GENE EXPRESSION IN NELLORE COWS

The aim of the present experiment was to verify the relationship among follicular diameter, ovulation rate, and gene expression of LH receptor (LHR) isoforms in order to know whether these aspects could or could not influence ovulation rates in Nellore cows. In Experiment 1, at a random stage of the estrous cycle (Day 0), Nellore cows (n = 53) received a progesterone intravaginal device (1.0 g, Primer®, Tecnopec, São Paulo, Brazil) and 2.5 mg of estradiol benzoate (EB; i.m. Estrogin®; Farmavet, São Paulo, Brazil). On Day 8, PGF2 (150 μg d-cloprostenol; Prolise® ARSA S.R.L., Buenos Aires, Argentina) was administered i.m. and the device was removed. Twenty-four hours after device removal, cows were treated i.m. with EB (1.0 mg) and, 48 h afterwards, ovulation was determined by ultrasonography (US; Aloka 900, Tokyo, Japan). Three days after ovulation, follicular growth was observed daily by US and cows were randomly allocated into 3 groups according to follicular diameter (mm) [G1 (7.0-8.0), G2 (8.1-9.0), and G3 (9.1-10.0)] to receive 6.25 mg of LH (i.m. Lutropin®-V, Bioniche, Belleville, Ontario, Canada), which corresponds to twice the minimum ovulatory dose (3.12 mg) as determined in a preliminary experiment. The results were analyzed by logistic regression (PROC GEN MOD, SAS Institute, Cary, NC). The ovulation rates were 9 (2/21), 36 (8/22), and 90% (9/10) for G1, G2, and G3, respectively. There were significant differences when comparing G1 v. G3 (P < 0.01), G2 v. G3 (P < 0.02), and G1 v. G2 (P < 0.03). In Experiment 2, granulosa and theca cells from Nellore cows were recovered from follicles obtained in a local abattoir and submitted to total RNA extraction and expression of LHR isoforms (LHR-B3, LHR-B4, LHR-B5, and LHR-B6) by semiquantitative RT-PCR using glyceraldehyde-3-phosphate dehydrogenase (GAPD) as the internal control. Follicles were dissected, measured with a paquimeter, and allocated in 3 groups according to follicular diameter (mm): A (8.0-9.0), B (9.1-10.0), and C (10.1-11.0). Considering that follicles measured with paquimeter are on average 1.0 mm larger than those measured by US, Groups A, B, and C correspond to Groups G1, G2, and G3 (Experiment 1). In order to select only nonatretic (healthy) follicles, the E2/P4 >1.0 ratio was used. Therefore, from a total of 400 ovaries, only 5, 4, and 4 granulosa (n = 13) and 7, 8, and 8 theca samples (n = 23) from Groups A, B, and C, respectively, were obtained. The data were analyzed by ANOVA and Pearson’s correlation. There were no significant differences in total LHR expression (LHR-B3 + LHR-B4 + LHR-B5 + LHR-B6) in theca cells from Groups A, B, and C. However, in granulosa cells, follicles from Group A had lower LHR expression (16.5; mRNA LHR/mRNA GAPD) compared with Group C (37.6; P < 0.05). There was a positive correlation between expression of LHR-B5 and LHR-B6 isoforms and an increase in follicular diameter. In conclusion, these preliminary results indicate that ovulatory capacity in Nellore cattle is related to an increase in follicular diameter and LHR expression in granulosa cells. R. A. L. Simões, R. A. Satrapa, and A. C. S. Castilho are recipients of fellowship and funding from FAPESP (São Paulo, Brazil).

230 EXPRESSION OF mRNA ENCODING FGF10 AND COGNATE RECEPTORS (FGFR1B AND FGFR2B) AROUND FOLLICLE DEVIATION IN NELORE HEIFERS

A member of the FGF7 subfamily, FGF10 acts via FGFR2B and FGFR1B. In bovine antral follicles, FGF-10 was detected in oocytes and theca cells (TC). Levels of mRNA were negatively correlated with intrafollicular concentrations of estradiol, and FGF10 inhibited estradiol production from granulosa cells (GC). In Nellore (Bos indicus), morphological divergence occurs on average 2.5 days after ovulation, when dominant follicle diameter is around 6.0 mm. To gain insight into the involvement of the FGF10 system in the control of follicle selection, we assessed mRNA expression of FGF10 in TC and of FGFR1B and FGFR2B in GC from dominant and subordinate follicles around deviation in Nellore heifers. Thirteen Nellore heifers were hormonally synchronized, and ovulation was detected by ultrasound monitoring every 12 h. Heifers were slaughtered 2 (n =4), 2.5 (n = 5), and 3 (n = 4) days after ovulation. Granulosa cells and TC were separated from the 2 largest follicles and submitted to total RNA extraction. mRNA abundance of CYP19 (aromatase), FGF10, FGFR1B, and FGFR2B was measured by real-time RT-PCR and normalized by the expression of cyclophilin A (CYCA) and GAPDH, for TC and GC, respectively. Dominant and subordinate follicles were considered those expressing the greatest and second-greatest abundance of CYP19 mRNA in GC within each heifer. Effects of follicle status and day on CYP19, FGF10, FGFR2B, and FGFR1B mRNA abundance were tested by ANOVA. On Day 2, FGFR2B mRNA abundance was greater in GC of subordinate follicles compared with dominant follicles (P = 0.006), and that of FGF10 in TC tended to exhibit the same pattern (P = 0.06). Follicle diameter was not different between dominant and subordinate follicles on Day 2 (5.5 ± 0 v. 5.12 ± 0.3 cm). On Day 2.5, FGF10 expression was greater in TC from subordinate follicles (P = 0.01), and FGFR2B expression in GC was no longer different between dominant and subordinate follicles. Follicle diameter was greater in dominant follicles on Day 2.5 (6.7 ± 0.2 v. 5.8 ± 0.3 cm; P = 0.04). On Day 3, no differences were observed between dominant and subordinate follicles for any of the genes assessed. mRNA expression of FGFR1B in GC did not change with follicle status or day. In conclusion, expression of FGF10 and FGFR2B was decreased in dominant follicles around morphological divergence, suggesting their involvement in the mechanisms controlling dominant follicle selection. As FGF10 inhibits estradiol production of GC, we propose that FGF10 and FGFR2B are suppressed in the dominant follicle to allow acquisition of full steroidogenic capacity. This research was supported by FAPESP.

212 EXPRESSION OF FIBROBLAST GROWTH FACTOR 18 (FGF18) AND COGNATE RECEPTORS (FGFR3C AND FGFR4) DURING LUTEAL DEVELOPMENT AND INDUCED LUTEOLYSIS IN CATTLE

Fibroblast growth factor receptor 2 (FGFR2) has been shown to induce luteinization in granulosa cells, luteal angiogenesis, and luteal growth. Alternative splicing of 4 genes give rise to 7 subtypes of fibroblast growth factor receptors (FGFR) with varying affinity for different fibroblast growth factors (FGF). Fibroblast growth factor receptor 2 and FGF18 efficiently activate FGFR3C and FGFR4 and may act in cooperation in tissues expressing these receptors. We aimed to determine mRNA expression patterns for FGF18, FGFR3C, and FGFR4 during bovine luteal development and following induced luteolysis. In addition, we assessed FGF18 localization in the bovine CL. Bovine CL were obtained from abattoir ovaries and classed into 4 stages of development: stage 1 =corpus hemorragicum; stage 2 = developing CL; stage 3 = mature or early functional luteolysis CL; and stage 4 = structural luteolysis. To assess FGF18 and FGFR mRNA expression during induced luteolysis, adult cows (Bos taurus Holstein-Friesians) were injected with the PGF2 analogue cloprostenol (500 mg i.m. Intervet, Unterschleissheim, Germany) during the mid-luteal phase of the cycle (Days 8-12). Corpus luteum were collected by transvaginal ovariectomy at 0, 0.5, 2, 4, 12, 24, 48, and 64 hr (n = 5/time point) after PGF2 injection. Tissue samples were submitted to total RNA extraction. Expression of FGF18, FGFR3C, and 4 mRNA during the bovine CL lifespan and induced luteolysis were measured by real-time RT-PCR with oligo-dT in the RT and bovine-specific primers in the PCR. Expression of cyclophilin was used as internal control. The effect of developmental stage and time post-PGF2 on gene expression was tested by ANOVA, followed by Tukey- Kramer HSD test. Immunohistochemical analysis was performed with a commercial human antibody (anti-FGF18; Santa Cruz Biotechnology, Santa Cruz, CA, USA). Fibroblast growth factor 18, FGFR3C, and FGFR4 mRNA was detected in all 4 developmental stages; FGF18 mRNA abundance was higher in stage 3 (2.89 ± 0.05; mean ± SEM) compared with stages 1 (0.3 ± 0.27), 2 (0.56 ± 1.27), and 4 (0.99 ± 0.32). Fibroblast growth factor 18 and FGFR4 mRNA expression did not significantly change during induced luteolysis. Fibroblast growth factor receptor 3C mRNA abundance peaked 4 h after PGF2 injection and significantly decreased at 24 h post-treatment in comparison with peak levels. Immunohistochemical analysis revealed the presence of FGF18 in small and large luteal cells and in blood vessels. In conclusion, the mRNA expression patterns of FGF18 and its receptors suggest their participation in the control of luteal differentiation, particularly during functional luteolysis. The localization of FGF18 protein to blood vessels suggests it may play a role in the control of angiogenesis in the bovine CL. Supported by CAPES/FAPESP.

210 EXPRESSION OF mRNA ENCODING STEROIDOGENIC ENZYMES IN THE DEVELOPING BOVINE OVARY

Recent findings suggest a role for estradiol in the regulation of early folliculogenesis. Estradiol production is greatest in the fetal ovary during early gestation in cattle, and both estradiol and progesterone inhibit primordial follicle activation (Yang MY and Fortune JE 2008 Biol. Reprod. 78 (Suppl 6), 1153-1161). Aromatase expression is detected in early stages of bovine pregnancy (Garverick HA et al. 2009 Anim. Reprod. Sci. in press). The mechanisms controlling steroidogenesis in the bovine fetal ovary remain to be fully elucidated. The objective of this study was to assess mRNA expression patterns of enzymes involved in steroid production [steroidogenic acute regulatory protein (STAR), side-chain cleavage P450 (CYP11), cytochrome P450 17 alpha-hydroxylase (CYP17A1), 3 beta-hydroxysteroid dehydrogenase (3fi-HSD), aromatase cytochrome P450 (CYP19), and 17 beta-hydroxysteroid dehydrogenase (17fi-HSD)] in bovine fetal ovaries during gestation. Bovine fetal ovaries were obtained in a local slaughterhouse, fetal age was estimated by the crown-rump length, and samples were grouped according with days of gestation as follows: 60 (n = 5), 75 (n = 8), 90 (n = 6), 120 (n = 7), 150 (n = 7), and 210 (n = 6). Expression of mRNA encoding steroidogenic enzymes was determined by semiquantitative real-time RT-PCR using bovine-specific primers and cyclophilin A as endogenous control. Reverse transcription was performed with SuperScriptIII® (Invitrogen, Carlsbad, CA, USA) and PCR with Power SYBR green master mix (Applied Biosystems, Foster City, CA, USA) in an ABI Prism® 7500 (Applied Biosystems). Gene expression values were determined by the Pfaffl equation and effect of day of gestation on gene expression was analyzed with Fisher’s protected test, except when data were not normally distributed and nonparametric analysis was performed. Expression of mRNA encoding all steroidogenic enzymes was detected throughout gestation. The mRNA abundance of CYP17A1 and CYP19 was highest at 60 days of gestation and decreased thereafter (P < 0.05). Expression of all other genes did not significantly vary with time of gestation. In conclusion, all major enzymes required for steroidogenesis were expressed in the bovine fetal ovary. Expression of CYP17A1 and CYP19 was suppressed after 60 days of gestation, suggesting that these enzymes may be involved in the mechanisms controlling estradiol production and follicle formation in the bovine fetal ovary. Supported by CAPES and FAPESP.

Expression of LH receptor mRNA splice variants in bovine granulosa cells: changes with follicle size and regulation by FSH in vitro

In cattle, most evidence suggests that granulosa cells express LH receptors (LHR) after (or as) the follicle becomes dominant, however there is some suggestion that granulosa cells from smaller pre-dominant follicles may express several LHR mRNA splice variants. The objective of this study was to measure LHR expression in bovine follicles of defined size and steroidogenic ability, and in granulosa cells from small follicles (<6 mm diameter) undergoing differentiation in vitro. Semiquantitative RT-PCR demonstrated that LHR mRNA was undetectable in granulosa cells of follicles <7 mm diameter (nondominant follicles), and increased with follicle diameter in follicles >7 mm diameter. Splice variants with deletions of exon 10 and part of exon 11 were detected as previously described, and we detected a novel splice variant with a deletion of exon 3. Cultured granulosa cells contained LHR mRNA, but with significantly greater amounts of variants with deletions of exon 10 and/or exon 11 compared with cells from dominant follicles. FSH increased the abundance of some but not all LHR mRNA splice variants in cultured granulosa cells. The addition of LH to cultured cells did not increase progesterone secretion, despite the presence of LHR mRNA. Collectively, these data suggest that granulosa cells do not acquire functional LHR until follicle dominance occurs.