Characterization of cytokine gene expression in uterine cytobrush samples of non-endometritic versus endometritic postpartum dairy cows

To better understand uterine inflammation in postpartum dairy cows we collected sequential cytobrush samples at 29-35 and at 49-55 d in milk (DIM). Based on the uterine cytology, cows were classified as Non-endometritic (n = 23; <18% neutrophils) or Endometritic (n = 12; ≥18% neutrophils) at 29-35 DIM and Non-endometritic (n = 17; <10% neutrophils) or Endometritic (n = 9; ≥10% neutrophils) at 49-55 DIM. Cows defined as Sham Controls (n = 6) were examined by vaginoscopy at 29-35 DIM and identified as Non-endometritic (<10% neutrophils) at 49-55 DIM. Cytokine gene expression in cytobrush samples was assessed using qRT-PCR. Sham Controls did not differ significantly (P > 0.17) from Non-endometritic cows at 49-55 DIM and these data were combined (n = 23). Uterine cytology-based classification using the aforementioned thresholds effectively separated cows into groups with Endometritic cows having significantly higher expression of pro-inflammatory (interleukin (IL)-1α, IL-1β, IL-6, IL-8, IL-17A CSF-1; P < 0.01) and regulatory (IL-1RA and IL-10; P < 0.03) cytokines, relative to Non-endometritic cows. Furthermore, Non-endometritic cows showed a significant decline (P < 0.03) in the expression of pro-inflammatory (IL-1α, IL-6, IL-8) and regulatory (IL-10) cytokine genes as the postpartum period progressed; whereas Endometritic cows exhibited a sustained elevation in transcript abundance throughout the sample period for both pro-inflammatory and regulatory cytokine genes. Expression of transforming growth factor (TGF) genes was more complex with TGF-β3 expression significantly (P < 0.01) lower at 29-35 DIM and TGF-β1 gene expression significantly (P < 0.03) increased at 49-55 DIM in Endometritic versus Non-endometritic cows. Expression of TGF-β2 gene was 2.7-fold higher (P < 0.01) at 29-35 DIM in cows that remained Endometritic when compared to cows recovering by 49-55 DIM. Some Non-endometritic cows (n = 4) at 29-35 DIM were reclassified as Endometritic at 49-55 DIM. The sampling procedures at 29-35 DIM did not alter either the cellular response (P > 0.43) or cytokine gene expression (P > 0.17) at 49-55 DIM. In conclusion, normal uterine involution is characterized by a progressive decline in pro-inflammatory and regulatory cytokine gene expression, while cows with endometritis show a dysregulated inflammatory process characterized by a sustained elevation in pro-inflammatory and regulatory cytokine gene expression. This analysis also shows that decreased TGF-β2 gene expression at 29-35 DIM may be an indicator of recovery from endometritis.

121 THREE-DIMENSIONAL ASSESSMENT OF EARLY CORPUS LUTEUM VASCULARITY IN BUFFALO (BUBALUS BUBALIS)

The aim of the study was to develop an objective method to assess the vascular flow to the early corpus luteum (CL) in buffaloes using colour Doppler ultrasound data. Our hypothesis was that 3-dimensional (3D) volumetric analysis of vascularity would demonstrate lower variability between animals compared with conventional 2-dimensional (2D) analysis of single images. Wave emergence and ovulation was synchronized in buffalo (n = 16) using prostaglandin-GnRH based protocols. Colour Doppler ultrasonography (MyLab5, 7.5-MHz linear array, colour gain 65%) was performed daily from Day −2 to 4 (Day 0 = ovulation). Video clips of the ovaries (20 s at 18–28 frames per second, AVI) were recorded by slow and uniform free-hand movement of the transducer. Day 4 CL was used for analysis of vascular area and volume. For 2D vascularity assessment, 3 images (800 × 652 pixels, RGB, BMP) of each CL (at maximum apparent vascularity) were acquired through the clip image function on the ultrasound machine and analysed by ImageJ (Fiji) software (NIH, Bethesda, MD, USA). For 3D vascularity assessment, a portion of the video clip encompassing an entire ovary was identified and exported as a series of 2D TIFF images using Videomach software. The ultrasound scale bar was used to calculate the number of pixels per millimetre and to calibrate the X (horizontal) and Y (vertical) dimensions. For 2D analyses, the CL boundary was drawn using the free-hand manual selection tool in Fiji, the area of the CL (mm2) was recorded, and the border was then enlarged by 1.5 mm to include the peripheral vascular region of the CL. The colour threshold was adjusted to select the vascular region. The 2D vascularity score was calculated as the ratio of the coloured area to the enlarged luteal area. For 3D volumetric analyses, each series of TIFF images was imported as an image sequence in Fiji and colour thresholding (similar to 2D analysis) was applied to save a second TIFF series containing luteal vascular regions (coloured areas) only. The remaining volumetric analyses were completed in Imaris software using the ovarian volume (original TIFF series) and luteal vascular volume (second TIFF series) as separate channels. The Z-dimension thickness of each image was estimated by using the dimensions of a follicle within the same ovary (Z-axis diameter = mean diameter along X- and Y-axes). Similar to 2D analyses, the volume of the CL was obtained by drawing a border along the edge of the CL, the CL border was enlarged by 1.5 mm, and a 3D vascularity score was obtained by building a surface on the luteal vascular image and calculating the vascular to luteal volume ratio. The 2D vascularity score differed from 3D vascularity score (0.21 ± 0.02 v. 0.13 ± 0.02, paired t-test P < 0.01); however, variance did not differ (Bartlett’s test P = 0.32). Our initial results support the notion that the described technique of quantifying vascular volume of the corpus luteum may decrease the technical variability during image assessment and therefore better reflect the true vascularity compared with 2D image analyses. Research was supported by a grant from the Natural Sciences and Engineering Research Council of Canada.

Comparison of follicular dynamics, superovulatory response, and embryo recovery between estradiol based and conventional superstimulation protocol in buffaloes (Bubalus bubalis)

Aim:

To evaluate the follicular dynamics, superovulatory response, and embryo recovery following superstimulatory treatment initiated at estradiol-17β induced follicular wave emergence and its comparison with conventional superstimulatory protocol in buffaloes.

Materials and Methods:

Six normal cycling pluriparous buffaloes, lactating, 90-180 days post-partum, and weighing between 500 and 660 kg were superstimulated twice with a withdrawal period of 35 days in between two treatments. In superstimulation protocol-1 (estradiol group) buffaloes were administered estradiol-17β (2 mg, i.m.) and eazibreed controlled internal drug release (CIDR) was inserted intravaginally (day=0) at the random stage of the estrous cycle. On the day 4, buffaloes were superstimulated using follicle stimulating hormone (FSH) 400 mg, divided into 10 tapering doses given at 12 hourly intervals. Prostaglandin F2α analogs (PGF2α) was administered at day 7.5 and day 8, and CIDR was removed with the second PGF2α injection. In superstimulation protocol - 2 (conventional group) buffaloes were superstimulated on the 10^th day of the estrous cycle with same FSH dose regimen and similar timings for PGF2α injections. In both groups, half of the buffaloes were treated with luteinizing hormone (LH) 25 mg and other half with 100 ug buserelin; gonadotrophin releasing hormone (GnRH) analog at 12 h after the end of FSH treatment. All buffaloes in both protocols were inseminated twice at 12 and 24 h of LH/GnRH treatment. Daily ultrasonography was performed to record the size and number of follicles and superovulatory response.

Results:

Significantly higher number of small follicles (<8 mm) was present at the time of initiation of superstimulatory treatment in the estradiol group compared to the conventional group (12.5±0.80 vs. 7.3±1.21, respectively, p=0.019), however, the number of ovulatory size follicles (≥8 mm) did not differ significantly between the respective groups (15.5±1.24 vs. 12.2±1.30; p=0.054). Total embryos and transferable embryos recovered were non-significantly higher in the estradiol group compared to the conventional group (5.83±0.86 vs. 4.67±1.16, p=0.328, and 3.67±0.93 vs. 2.67±0.68, p=0.437, respectively). The significant higher proportion of transferable embryos were recovered in buffaloes treated with LH compared to GnRH (73.3% vs. 48.5%; p=0.044).

Conclusion:

The average number of ovulatory size follicles (>8 mm), corpora lutea, and transferable embryos was higher in buffaloes superstimulated at estradiol-induced follicular wave compared to the conventional protocol: Further the percentage of transferable embryos was significantly higher in buffaloes administered with LH compared to GnRH.

Organelle reorganization in bovine oocytes during dominant follicle growth and regression

BACKGROUND

We tested the hypothesis that organelles in bovine oocytes undergo changes in number and spatial distribution in a manner specific for phase of follicle development.

METHODS

Cumulus-oocyte-complexes were collected from Hereford heifers by ultrasound-guided follicle aspiration from dominant follicles in the growing phase (n = 5; Day 0 = ovulation), static phase (n = 5), regressing phase (n = 7) of Wave 1 and from preovulatory follicles (n = 5). Oocytes were processed and transmission electron micrographs of ooplasm representing peripheral, perinuclear and central regions were evaluated using standard stereological methods.

RESULTS

The number of mitochondria and volume occupied by lipid droplets was higher (P < 0.03) in oocytes from regressing follicles (193.0 ± 10.4/1000 μm(3) and 3.5 ± 0.7 %) than growing and preovulatory stages (118.7 ± 14.4/1000 μm(3) and 1.1 ± 0.3 %; 150.5 ± 28.7/1000 μm(3) and 1.6 ± 0.2 %, respectively). Oocytes from growing, static and preovulatory follicles had >70 % mitochondria in the peripheral regions whereas oocytes from regressing follicles had an even distribution. Oocytes from growing follicles had more lipid droplets in peripheral region than in central region (86.9 vs. 13.1 %). Percent surface area of mitochondria in contact with lipid droplets increased from growing (2.3 %) to static, regressing or preovulatory follicle stage (8.9, 6.1 and 6.2 %). The amount, size and distribution of other organelles did not differ among phases (P > 0.11).

CONCLUSIONS

Our hypothesis was supported in that mitochondrial number increased and translocation occurred from a peripheral to an even distribution as follicles entered the regressing phase. In addition, lipid droplets underwent spatial reorganization from a peripheral to an even distribution during the growing phase and mitochondria-lipid contact area increased with follicle maturation.

Effect of superstimulation protocols on nuclear maturation and distribution of lipid droplets in bovine oocytes

Our objective was to study the effect of superstimulation protocols on nuclear maturation of the oocyte and the distribution of lipid droplets in the ooplasm. Heifers (n = 4 each group) during the luteal phase were either treated with FSH for 4 days (Short FSH), FSH for 4 days followed by 84 h of gonadotropin free period (FSH Starvation) or for 7 days (Long FSH) starting from the day of wave emergence. In all groups, LH was given 24 h after induced luteolysis (penultimate day of FSH) and cumulus–oocyte complexes were collected 24 h later. Oocytes were stained for nuclear maturation (Lamin/chromatin) and lipid droplets (Nile red). The Long FSH group had a greater proportion of mature oocytes (metaphase II) compared with heifers in the Short FSH and FSH Starvation groups (59/100 vs 5/23 and 2/25, respectively; P < 0.01). On average across all groups, oocytes contained 22 pL of lipids (3.3% of ooplasm volume) distributed as 3000 droplets. Average volume of individual lipid droplets was higher in the FSH Starvation (11.5 ± 1.5 10–3 pL, P = 0.03) compared with the Short and Long FSH groups (7.2 ± 0.6 10–3 and 8.0 ± 0.8 10–3 pL, respectively). In conclusion, both FSH Starvation and Short FSH treatments yielded a lower proportion of mature oocytes compared with the Long FSH treatment. Furthermore, FSH starvation led to an accumulation of larger lipid droplets in the ooplasm, indicating atresia. Our results indicate that a longer superstimulation period in beef cattle yields higher numbers and better-quality oocytes.

176 BLOOD FLOW TO THE CORPUS LUTEUM AND PREOVULATORY FOLLICLE AFTER OVULATION INDUCTION DURING FIRST VERSUS SECOND WAVE IN WATER BUFFALO

The objective of the study was to compare the blood flow to the corpus luteum (CL) and the preovulatory follicle in dairy buffalo (Bubalus bubalis) when ovulation was induced during the first (low to increasing progesterone levels) versus the second (luteal progesterone levels) follicular wave. We hypothesised that the wall of the first-wave dominant follicle will be less vascular compared with that of the second-wave follicle. The study was conducted during the summer months in Punjab, India. Ovulation was synchronized with prostaglandin F2α (PGF) IM followed by gonadotropin-releasing hormone (GnRH) IM 48 h later (Day 0) and buffaloes were randomised to first wave (FW; n = 6) and second wave (SW; n = 7) groups. FW group was given PGF on Days 6.5 and 7, and GnRH on Day 9.5 followed by AI (14–16 h after GnRH). The SW group was given GnRH on Day 7 (to induce ovulation of first-wave dominant follicle without luteolysis and synchronous emergence of next wave), PGF on Days 13.5 and 14, GnRH on Day 16.5 followed by artificial insemination. Transrectal colour Doppler ultrasonography (MyLab5 Vetwith 7.5 MHz transducer, Esaote S.p.A, Genoa, Italy) was performed daily and 20-s cineloops of each ovary were recorded under standardized gain controls. Images from the cineloops were processed using Fiji (ImageJ, National Institutes of Health, Bethesda, MD, USA) to calculate the area of blood flow (coloured area = vascular area, grey scale area = tissue area, and their ratio) for the preovulatory follicle (on the day before ovulation) and luteal tissue (on the day of PGF injection and 4 days post-ovulation). Data were analysed by t-test from the animals that ovulated one day before (n = 3) or the day of AI (n = 6) and had a functional CL at day 5 post-AI (FW n = 5, SW n = 4). FW follicles ovulated on 8.6 ± 0.3 days from wave emergence compared with SW follicles on 10.0 ± 0.6 days (P < 0.05) but were similar in size (i.e. follicular area on the day before ovulation did not differ between groups; P = 0.5). There was no difference in the blood flow area in the wall of preovulatory follicles (P = 0.4). Vascular area of follicles was strongly correlated with their diameter (r = 0.87). Follicles >13.5 mm in diameter had more blood flow in their wall than smaller follicles (P < 0.01). FW had a tendency (P = 0.07) for smaller luteal area on the day of PGF treatment (FW = 171 ± 24 mm2; SW = 332 ± 81 mm2) and tended (P = 0.06) to have less vascular area in the CL compared to SW group (FW = 30 ± 6 mm2; SW = 67 ± 17 mm2). There was no difference (P = 0.5) between the groups for vascular to CL area ratio. The area of luteal tissue and blood flow to the CL at Day 4 post-ovulation did not differ between the groups (P = 0.4). The diameter of the preovulatory follicle (11.6–15.7 mm) was not correlated with the cross-sectional area of developing CL at Day 4 post-ovulation (r = 0.09). In conclusion, vascularity to preovulatory follicles originating from the first wave v. second wave did not differ and preovulatory follicles ≥13.5 mm were more vascular than smaller follicles. Research was funded by NSERC; the first author was funded by scholarships from WCVM and GADVASU.

287 EFFECT OF FOLLICULAR AGING ON THE ATP CONTENT AND DISTRIBUTION OF MITOCHONDRIA IN BOVINE OOCYTES

Our objective was to determine how follicular aging affects the distribution and content of mitochondrial population and ATP in in vivo-matured bovine oocytes. We hypothesised that in vivo-matured bovine oocytes obtained from aged follicles (84 h of gonadotropin starvation) have altered mitochondrial distribution and decreased cytoplasmic ATP content compared to those obtained immediately at the end of a superstimulatory protocol (no starvation). Follicular waves were synchronized by ablation 5 to 8 d after ovulation and a CIDR device was given. Starting on the day of wave emergence (Day 0), short FSH and FSH starvation groups (n = 5 heifers each) were given 8 doses of FSH im over 4 d and the long FSH group (n = 4) was given 14 doses over 7 d. Two doses of PGF were given on Day 4 (short FSH) or Day 7 (FSH starvation and long FSH groups), the CIDR was removed, and LH was given 24 h after second PGF treatment. The ovaries were removed 24 h later by colpotomy and cumulus-oocyte-complexes (COC) were collected from follicles ≥8 mm. Denuded oocytes were either stained with Mitotracker Deep Red FM and imaged by confocal microscopy or processed for ATP assay. Mitochondria numbers were assessed by segmentation of 3D datasets. Proportions of COC within each grade were compared using Fischer's exact test, and ATP and mitochondrial data were compared by analysis of variance. Short and long FSH groups had a greater proportion of Grade 1 expanded COC than the FSH starvation group (P = 0.02). The ATP content of oocytes (from expanded COC) tended to be higher in the long FSH group than short FSH (P = 0.09), and the FSH starvation group was intermediate. The ATP content of oocytes from compact COC did not differ among groups (P = 0.49). The proportion of mitochondrial clusters was highest (P = 0.01) and the proportion of individual mitochondria was lowest (P = 0.01) in the FSH starvation group compared to short and long FSH groups. Mitochondria from the long FSH and FSH starvation groups had twice the relative intensity compared to the short FSH group (P < 0.01). In conclusion, follicular aging (FSH starvation) was associated with a decrease in oocyte morphologic grade and marked clustering of mitochondria, which may be a reflection of oxidative stress and atresia.

313 EFFECT OF DURATION OF THE GROWING PHASE OF OVULATORY FOLLICLES IN SUPERSTIMULATED HEIFERS ON OOCYTE COMPETENCE AFTER IN VITRO FERTILIZATION

We tested the hypotheses that extending the duration of follicular growth by superstimulation increases oocyte competence, and that FSH starvation at the end of superstimulatory treatment decreases oocyte competence. Heifers were allocated randomly to short FSH duration (n = 8), FSH starvation (n = 8), or long FSH duration (n = 8) groups. Five to 8 days after ovulation, transvaginal ultrasound-guided follicle ablation was done to synchronize follicle wave emergence, and a progesterone-releasing device (CIDR; Pfizer Animal Health, New York, NY, USA) was placed intravaginally. Short FSH and FSH starvation groups were given 8 doses of FSH (Folltropin-V; Bioniche Animal Health Inc., Belleville, ON, Canada) IM, whereas the long FSH group was given 14 doses of FSH at 12-h intervals, starting from the day of wave emergence (Day 0). Prostaglandin F2α (PGF) was administered twice, 12 h apart, on Day 3 in the short FSH group and on Day 6 in the other 2 groups. In all heifers, the CIDR was removed at the time of the second PGF treatment; pLH (Lutropin-V; Bioniche Animal Health Inc.) was given IM 24 h after CIDR removal, and cumulus–oocyte complexes (COC) were collected 24 h after pLH treatment. The COC were matured in vitro (6 h) and fertilized (IVF), and the embryos were cultured for 10 days. At 12 h after pLH, the long FSH group had a greater number of ≥9 mm follicles than the FSH starvation and short FSH groups (25.4 ± 5.3 v. 11.0 ± 2.1 and 10.6 ± 2.3, respectively; P < 0.03). The long FSH group also had more expanded COC than the FSH starvation group (P < 0.001), but did not differ from the short FSH group (93, 54, and 74%, respectively). The FSH starvation group had a greater proportion (P < 0.0001) of partially expanded COC (32%) and poor quality oocytes (70%) than did the long (1 and 33%) and short (4 and 45%) FSH groups; oocyte quality did not differ between long and short FSH groups. At 48 h after IVF, the cleavage rate was lower in the FSH starvation group compared with the short and long FSH groups (35, 54, and 56%, respectively; P = 0.003). After 9 days in culture, embryo development (morula + blastocyst) in the FSH starvation group was lower than that in the long FSH group, (18 v. 37%; P = 0.04), but did not differ from that in the short FSH group (25%). After removal of the data of one heifer in the FSH starvation group that produced 52% of total embryos in that group (outlier), the Day 9 blastocyst rate was lower in the FSH starvation group than in the short and long FSH groups (2% v. 14 and 21%, respectively; P = 0.02). In conclusion, extending the standard superstimulation protocol by 3 days enhanced ovarian response to FSH treatment, but did not improve oocyte competence, whereas a period of FSH starvation after FSH treatment compromised oocyte quality and embryo development.

Ultrasonographic evaluation of uterine involution and postpartum follicular dynamics in French Jennies (Equus asinus)

Uterine involution and follicular dynamics during postpartum period were studied ultrasonographically in French jennies. For the study of uterine involution in postpartum jennies (n = 6, Group S), sonographic measurements of different parts of the uterus and endometrium were made at three-day interval, starting from the day of foaling and continued up to 33 days postpartum. Uterine dimensions were also recorded in non-pregnant jennies (n = 3, Group C) throughout a cycle and compared with the dimensions of Group S jennies observed on the day of complete involution. Follicular dynamics of first and second postpartum ovulatory cycles were studied and compared with that of the single estrous cycle of Group C jennies. Jugular venous blood samples of Group S jennies were collected at weekly intervals for 49 days, commencing at the appearance of first preovulatory follicle, to support the sonographic findings. The average involution period was 22.5 +/- 1.7 days. However, it was significantly delayed (P < 0.05) in jennies which came into first postpartum ovulatory heat within Day 9 than those who came later (25.0 +/- 1.0 versus 20.0 +/- 1.0). The endometrial layer was not discernible beyond Day 15 postpartum and thus was found to be unreliable index of uterine involution. The follicular growth rate (mm per day) and diameter (mm) of preovulatory follicle in postpartum jennies were similar to that in normal cycling jennies (P > 0.05). The first and second ovulations occurred at 14.6 +/- 0.8 and 39.0 +/- 0.8 days postpartum in Group S jennies. All the corpora lutea, either echogenic or centrally non-echogenic were functionally similar and had similar life span (P > 0.05). In conclusion, the postpartum reproductive events related to uterine involution and ovarian cyclicity apparently resemble that of mares.