108 IS THE BINDING OF COXIELLA BURNETII TO THE ZONA PELLUCIDAE FOLLOWING IN VITRO INFECTION OF IN VITRO-PRODUCED GOAT EMBRYOS CONCENTRATION DEPENDENT?

Previous experiments using in vitro infection have shown that at concentrations of 109 bacteria/mL, Coxiella burnetii strongly adheres to the zona pellucidae (ZP) of caprine embryos produced in vitro or in vivo (Alsaleh et al., 2013). However, spontaneous infection results in bacterial concentrations of between 106 and 107 bacteria/mL (Rodolakis, 2006; Alsaleh et al., 2011). The aim of this study was to determine whether the concentration of Coxiella burnetii affected its ability to bind to the ZP in vitro. A total of 120 ZP-intact 8- to 16-cell embryos, produced in vitro from ovaries collected at slaughter, were infected with Coxiella burnetti (strain CbC1) produced via ovoculture at 109 mL−1 (3 batches of 10 embryos), 107/mL (5 batches of 10 embryos), 105 mL−1 (3 batches of 8 embryos). After overnight incubation at 37°C in 5% CO2, the embryos were recovered and washed in batches, in 10 successive baths of PBS with 5% FCS, in accordance with International Embryo Technology Society guidelines. The 10 wash baths were collected separately and centrifuged for 1 h at 13,000 × g. The presence of C. burnetii was determined by conventional PCR in each batch of embryos and in the pellets of the 10 wash baths (Table 1). As demonstrated previously, Coxiella DNA was detected in embryo batches after 10 washes when a concentration of 109 bacteria/mL was used for in vitro infection, but this binding property did not occur at lower bacterial concentrations. We can conclude that the attachment of Coxiella burnetii to the zona pellucida of in vitro-produced embryos is concentration dependent. This finding illustrates the limitations of in vitro experiments to study the risk of pathogen transmission via embryo transfer. Table 1. Detection of Coxiella burnetii (CB) in successive embryo washing baths and batches of 8 to 10 infected ZP-intact 8- to 16-cell embryos after 10 wash cycles, using conventional PCR (C-PCR), as a function of the concentration of CB used for in vitro infection and determined by quantitative PCR (Q-PCR)

Can Chlamydia abortus be transmitted by embryo transfer in goats?

The objectives of this study were to determine (i) whether Chlamydia abortus would adhere to or penetrate the intact zona pellucida (ZP-intact) of early in vivo-derived caprine embryos, after in vitro infection; and (ii) the efficacy of the International Embryo Transfer Society (IETS) washing protocol for bovine embryos. Fifty-two ZP-intact embryos (8-16 cells), obtained from 14 donors were used in this experiment. The embryos were randomly divided into 12 batches. Nine batches (ZP-intact) of five embryos were incubated in a medium containing 4 × 10(7)Chlamydia/mL of AB7 strain. After incubation for 18 hours at 37 °C in an atmosphere of 5% CO2, the embryos were washed in batches in 10 successive baths of a phosphate buffer saline and 5% fetal calf serum solution in accordance with IETS guidelines. In parallel, three batches of ZP-intact embryos were used as controls by being subjected to similar procedures but without exposure to C. abortus. The 10 wash baths were collected separately and centrifuged for 1 hour at 13,000 × g. The washed embryos and the pellets of the 10 centrifuged wash baths were frozen at -20 °C before examination for evidence of C. abortus using polymerase chain reaction. C. abortus DNA was found in all of the infected batches of ZP-intact embryos (9/9) after 10 successive washes. It was also detected in the 10th wash fluid for seven batches of embryos, whereas for the two other batches, the last positive wash bath was the eighth and the ninth, respectively. In contrast, none of the embryos or their washing fluids in the control batches were DNA positive. These results report that C. abortus adheres to and/or penetrates the ZP of in vivo caprine embryos after in vitro infection, and that the standard washing protocol recommended by the IETS for bovine embryos, failed to remove it. The persistence of these bacteria after washing makes the embryo a potential means of transmission of the bacterium during embryo transfer from infected donor goats to healthy recipients and/or their offspring. Nevertheless, the detection of C. abortus DNA by polymerase chain reaction does not prove that the bacteria found was infectious. Further studies are required to investigate whether enzymatic and/or antibiotic treatment of caprine embryos infected by C. abortus would eliminate the bacteria from the ZP.

Evaluation of viability and apoptosis in horse embryos stored under different conditions at 5 degrees C

The aim of this study was to evaluate the viability (percentage of dead cells) and the incidence of DNA fragmentation of horse embryos after storage in three different media at 5 degrees C for 6 and 24 h. Forty embryos were stored in Emcare Holding Solution for 6 and 24 h, in Hams'F10 or Vigro Holding Plus for 24 h at 5 degrees C (n = 9-10 per group) and 10 embryos were evaluated immediately after collection. First, embryos were stained, immediately after collection or following storage, to detect dead cells (DAPI) and, subsequently, DAPI-stained embryos were fixed and stained to detect DNA fragmentation (TUNEL). Finally, all the fixed embryos were re-stained with DAPI to determine the total number of cells. The percentage of cells stained with both TUNEL and DAPI or TUNEL-only or DAPI-only were determined. The percent of dead cells (DAPI-labelled) per embryo increased with duration of storage, but no differences were detected between the storage media. The percentage of early apoptotic cells (TUNEL+/DAPI-) in fresh and stored embryo for 6 h or 24 h did not differ significantly (P > 0.05). There was a significant correlation between the percentage of cells labelled by TUNEL and DAPI (R = 0.87) (P < 0.001). These results suggest that cooled storage increases cell death but this does not appear to occur by induction of apoptosis and that DAPI staining proves to be a quick and reliable method for assessing embryo viability.

Early embryonic cells from in vivo-produced goat embryos transmit the caprine arthritis–encephalitis virus (CAEV)

The aim of this study was to investigate whether cells of early goat embryos isolated from in vivo-fertilized goats interact with the caprine arthritis-encephalitis virus (CAEV) in vitro and whether the embryonic zona pellucida (ZP) protects early embryo cells from CAEV infection. ZP-free and ZP-intact 8-16 cell embryos were inoculated for 2 h with CAEVat the 10(4) tissue culture infectious dose 50 (TCID50)/ml. Infected embryos were incubated for 72 h over feeder monolayer containing caprine oviduct epithelial cells (COECs) and CAEV indicator goat synovial membrane (GSM) cells. Noninoculated ZP-free and ZP-intact embryos were submitted to similar treatments and used as controls. Six days postinoculation, infectious virus assay of the wash fluids of inoculated early goat embryos showed typical CAEV-induced cytopathic effects (CPE) on indicator GSM monolayers, with fluids of the first two washes only. The mixed cell monolayer (COEC + GSM) used as feeder cells for CAEV inoculated ZP-free embryos showed CPE. In contrast, none of the feeder monolayers, used for culture of CAEV inoculated ZP-intact embryos or the noninoculated controls, developed any CPE. CAEV exposure apparently did not interfere with development of ZP-free embryos in vitro during the 72 h study period when compared with untreated controls (34.6 and 36% blastocysts, respectively, P > 0.05). From these results one can conclude that the transmission of infectious molecularly cloned CAEV-pBSCA (plasmid binding site CAEV) by embryonic cells from in vivo-produced embryos at the 8-16 cell stages is possible with ZP-free embryos. The absence of interactions between ZP-intact embryos and CAEV in vitro suggests that the ZP is an efficient protective embryo barrier.

Comparison of two protocols with a progesterone antagonist aglepristone (RU534) to induce parturition in bitches

Parturition was induced in ten Beagle bitches by injecting them subcutaneously with 15 mg aglepristone kg-1 (Alizine) at day 58 of gestation and 24 h later and subsequently at 2 h intervals with either 0.08 mg alfaprostol kg-1 (Alfabedyl) (group 1; five bitches) or 0.15 iu oxytocin kg-1 (Ocytocine S) (group 2; five bitches). Blood samples were collected every 4 h until the end of parturition to assay plasma concentrations of progesterone, dihydro-keto prostaglandin F2 alpha (PGFM), oxytocin, prolactin and cortisol. Parturition occurred in all bitches. The mean time of onset of parturition for both groups was not significantly different (32.6 +/- 3.7 h for group 1 versus 31.6 +/- 3.6 h for group 2), although the mean expulsion time for bitches from group 2 (4.5 +/- 1.8 h) was significantly shorter than that of bitches in group 1 (9.1 +/- 2.0 h). At birth, 93% of the pups were alive in group 2 compared with 86% in group 1. Peripheral plasma concentrations of progesterone increased significantly after the administration of aglepristone, but direct or indirect luteolysis was not induced, and plasma concentrations of oxytocin or cortisol did not change during the first 24 h after administration of aglepristone. PGFM concentrations increased significantly after 4 h of aglepristone administration. During the first 20 h after aglepristone administration, prolactin concentrations increased significantly. At parturition, bitches in group 2, which had the shorter expulsion time of pups, were characterized by significantly higher concentrations of oxytocin and PGFM than bitches in group 1.

Hormonal variation in bitches after early or mid-pregnancy termination with aglepristone (RU534)

Seven bitches in early pregnancy (12.8 +/- 3.8 days after ovulation; group 1) and seven bitches in mid-pregnancy (32.0 +/- 1.53 days after ovulation; group 2) were used in this study. For each group, five bitches were treated with 0.10 mg aglepristone (Alizine) kg-1 and this dose was repeated 24 h later. Two control bitches received a placebo. Blood samples were collected at 6 h intervals to determine plasma concentrations of progesterone, dihydro-keto prostaglandin F2 alpha (PGFM), oxytocin, prolactin and cortisol. Parturition occurred in the four control bitches. All bitches treated with aglepristone aborted. In group 1, embryonic death occurred; in group 2, fetal expulsion occurred 60-132 h after administration of aglepristone. After pregnancy termination, the interoestrous interval of aglepristone-treated bitches was significantly shorter than that before treatment. Treatment with aglepristone did not modify plasma concentrations of progesterone, prostaglandin, oxytocin or cortisol within 24 h after its administration, but it induced, in mid-pregnancy (group 2) a discharge of prolactin within 12 h after its administration. As an abortifacient, aglepristone acted on the uterus and, therefore, did not have direct or immediate luteolytic properties. Termination of pregnancy occurred with high plasma progesterone concentrations. Fetal expulsion was characterized by an increase in the concentration of PGFM, but oxytocin and cortisol remained at basal concentrations.

Use of buserelin to induce ovulation in the cyclic mare

Inducing ovulation in a cyclic mare is often necessary. For this purpose, hCG has been used commonly, but the response can be reduced after successive administrations. The aims of this study were to test the effectiveness of buserelin in hastening ovulation in estrus mares, and its influence on fertility; and to investigate the effect of treatment on LH secretion. Five crossover trials were designed to compare the effect of two treatments: buserelin (40 microg in 4 doses i.v. at 12 h intervals) vs placebo (Experiments 1 and 2); buserelin 40 microg (in 4 doses i.v.) vs 20 microg (Experiment 3); buserelin (4 doses of 20 microg i.v.) vs hCG (1 dose of 2,500 IU i.v.) (Experiment 4); or buserelin (3 doses of 13.3 microg at 6 h interval) vs hCG (Experiment 5). In Experiment 2, blood samples were taken hourly until ovulation, for LH measurements. In Experiment 1, buserelin treatment significantly hastened ovulation. Reduction of the dose by half (Experiment 3) did not alter the effectiveness. In Experiments 4 and 5, buserelin was as effective as hCG in inducing ovulation between 24 and 48 h after initiation of treatment. Buserelin treatment induced a rise in LH concentration during the 48 h period of the experiment, and LH concentrations before ovulation were significantly higher in buserelin treated cycles than in placebo cycles. These experiments demonstrated the usefulness of two new protocols of administration of buserelin, as an alternative to hCG for induction of ovulation. One hypothesis explaining the mechanism of action is that the persistant rise in LH concentration could modify the ratio of biological/immunological LH, as it occurs physiologically, thereby hastening ovulation.

Quantitative histological analysis of equine embryos at exactly 156 and 168 h after ovulation

Equine embryos were collected at exactly 156 +/- 0.5 (n=8) and 168 +/- 0.5 h (n=11) after ovulation. The embryos were fixed in glutaraldehyde, sectioned serially and observed using light microscopy. In the 156 h group, all embryos were early blastocysts except for one, which was a morula. The morula and one early blastocyst had no capsule. The capsules of the other embryos were thin. The mean +/- SD total number of cells was 275 +/- 105 (range 117-417). The mean +/- SD proportions of mitotic and pycnotic cells were 2.5 +/- 1.2 and 1.1 +/- 1.8%, respectively, and there were no differences between each inner cell mass (ICM) and trophoblast. The mean +/- SD proportion of ICM cells was 36.5 +/- 5.2%. In the 168 h group, there were early, mid- and expanded blastocysts, all of which had a capsule. The mean +/- SD total number of cells was 1093 +/- 666 (range 272-2217). The mean +/- SD proportions of mitotic and pycnotic cells were 3.5 +/- 1.4% and 0.1 +/- 0.03%, respectively, and there were no differences between each ICM and trophoblast. The mean +/- SD proportion of ICM cells was 21.1 +/- 9.7%. In the 168 h group, there was a significant correlation (P < 0.01) between the total number of cells and the diameters and proportions of ICM cells. The 168 h embryos were composed of significantly (P < 0.01) more cells (approximately four times) than were the 156 h embryos but had lower proportions of ICM cells. These results indicate that in equine embryos there is: (i) an individual (perhaps seasonal) variability in the rate of development; (ii) a doubling in the number of cells every 6 h between 156 h and 168 h after ovulation; and (iii) a decrease in the proportion of ICM cells between the early and expanded blastocyst stages of development.

Comparison of the cryoprotectant properties of glycerol and ethylene glycol for early (day 6) equine embryos

Early (day 6) equine embryos (n=23) were assigned to four treatment groups to assess the cryoprotectant properties of glycerol and ethylene glycol and the effect of adding sucrose during removal of the cryoprotectant: (i) group GG (n=5) embryos were frozen and thawed using 1.5 mol glycerol l(-1) as the cryoprotectant, which was added at 22 degrees C in four steps (0.375, 0.75, 1.125 and 1.5 mol glycerol l(-1)), and removed after thawing in five steps (1.5, 1.125, 0.75, 0.375 and 0.0 mol glycerol l(-1)); (ii) group GS (n=6) embryos were frozen and thawed using 1.5 mol glycerol l(-1) as for group GG, except that 0.25 mol sucrose l(-1) was added during removal of the glycerol; (iii) group EE (n = 6) embryos were frozen and thawed using 1.5 mol ethylene glycol l(-1) as the cryoprotectant, which was added in three steps (0.5, 1.0 and 1.5 mol ethylene glycol l(-1)) and removed after thawing in four steps (1.5, 1.0, 0.5, 0.0 mol ethylene glycol l(-1)); and (iv) group ES (n = 6) embryos were frozen and thawed using 1.5 mol ethylene glycol l(-1) as for group EE, except that 0.25 mol sucrose l(-1) was added during removal of the ethylene glycol. After thawing, the embryos were incubated at 37 degrees C in Ham's F10 medium supplemented with 10% (v/v) fetal calf serum and antibiotics, in 5% CO2 in air for 6 h. The embryos were fixed in glutaraldehyde, serially sectioned and observed using light microscopy. None of the frozen-thawed embryos treated with ethylene glycol (groups EE and ES) had any viable cells. There were no lysed cells in the frozen-thawed embryos treated with glycerol (groups GG and GS) and the proportion of cells with pyknotic nuclei was low (group GG = 1.1 +/- 0.8% and group GS = 2.5 +/- 1.5%). There were no differences between embryos treated with cyroprotectant diluted with or without sucrose. The embryos were morulae or early blastocysts and either did not have a capsule or had a very thin capsule. The results of the present study confirm that ethylene glycol is a poor cryoprotectant for early equine embryos and that the use of sucrose during dilution of the cryoprotectant after thawing does not improve the morphology of the embryos. The results of this study also indicate that glycerol is an effective cryoprotectant for freezing equine embryos with intact zonae pellucidae and with either very thin or no capsules.

Clinical protocol for pregnancy termination in bitches using prostaglandin F2 alpha

Sixty-seven pregnant bitches were given atropine sulphate (0.025 mg kg-1), prifinium bromide (0.1 ml kg-1) and metopimazine (0.5 mg kg-1) and 15 min later 2.5 micrograms cloprostenol kg-1 s.c., three times at 48 h intervals (day 1, day 3, day 5). After one treatment, 53 of the 67 bitches had aborted, and after a second treatment, 62 of the 67 bitches had aborted. In 18 bitches, progesteronemia kinetics were followed-up: the first injection of cloprostenol resulted in a significant (P < 0.01) fall in progesteronemia. In 12 of the 18 bitches that had aborted following the first protocol, this rapid fall in progesterone was noteworthy as it decreased progesterone concentration on average from 17.07 +/- 8.20 ng ml-1 on day 1 to 1.31 +/- 0.34 ng ml-1 on day 3. The premedication administered 15 min before the injection of prostaglandins, prevented the appearance of side effects in 39 of the 67 bitches (58.2%).

Success rates when attempting to nonsurgically collect equine embryos at 144, 156 or 168 hours after ovulation

The purpose of this study was to evaluate the exact age when the equine embryo reaches the uterus. The time of ovulation was determined by hourly ultrasound examinations starting 32 h after an injection of crude equine pituitary gonadotrophin or human chorionic gonadotrophin, or after the first of 4 injections of buserelin. Nonsurgical uterine flushings were carried out 144 h (Day 6), 156 h (Day 6.5) or 168 h (Day 7) after ovulation. Induction of ovulation was attempted in 101 oestrous cycles and 61 of 101 mares (60.4%) ovulated 32-44 h post injection. Sixty embryo collections were performed which yielded: 0/20 embryos at 144 h, 9/17 embryos (53%) at 156 h and 12/23 embryos (52%) at 168 h. The mean (+/- s.e.m.) diameter of the embryo was significantly greater (P<0.01) at Day 7 (244 +/- 15 microm) than at Day 6.5 (186 +/- 9.1 microm), and variability in size was observed among embryos collected from the same mare after synchronous natural multiple ovulations. These results suggest that; i) horse embryos enter the uterus between 144 and 156 h after ovulation, and ii) the time interval between ovulation and fertilisation in mares is inconsistent and/or embryonic development rate may differ between individual embryos.

The effect of propanediol on the morphology of fresh and frozen equine embryos

Seventeen horse embryos recovered on the sixth day after spontaneous ovulation were; 1) washed in PBS (n = 6), 2) treated with 1.5 M 1-2 propanediol (n = 6) or, 3) frozen and thawed using 1.5 M propanediol as the cryoprotectant (n = 5). After treatment, the embryos were incubated for 6 h in medium before they were fixed, serially sectioned and examined microscopically to count the total numbers of interphase, mitotic and pycnotic nuclei. Significant differences were measured only in the mean proportions of pycnotic cells (+/- s.d.), both between the control (9.2 +/- 7.3%) and frozen-thawed embryos (52.8 +/- 37.1%; P<0.05) and between the propanediol-treated (10.8 +/- 4.6%) and the frozen-thawed embryos (P<0.01). Propanediol appears to be minimally toxic to equine embryos but it is a poor cryoprotectant.

Evaluation of cryopreservation techniques for goat embryos

A total of 410 goat embryos were divided at random into 9 groups. Cryoprotectants (glycerol, ethylene glycol or dimethylsulfoxide) were added by a 3-step procedure using increasing concentrations of cryoprotectant (0.5 M; 1 M; 1.5 M) in PBS at 10 min intervals. After freezing and thawing, each cryoprotectant was removed by 3 methods: the classic 3-step procedure (cryoprotectant 1 M-10 min; 0.5 M-10 min; PBS alone-10 min); the same procedure, but with sucrose added to the first 2 steps (sucrose 0.25 M and cryoprotectant 1 M-10 min; sucrose 0.25 M and cryoprotectant 0.5 M-10 min; PBS alone-10 min); and a 2-step procedure with sucrose alone (sucrose 0.25 M-10 min; PBS alone-10 min). Each removal protocol was performed for embryos in each cryoprotectant. The viability of the embryo was evaluated by its capacity to subsequently develop during 48 h in vitro culture. For morulae the development rate of the embryos was significantly higher when they were frozen with ethylene glycol than when dimethylsulfoxide or glycerol was used (P < 0.05). For blastocysts the development rate was the same whether they had been frozen with ethylene glycol or dimethylsulfoxide, and was significantly lower when they were frozen with glycerol (P < 0.05). Among the 3 removal procedures tested, the 3-step procedure with sucrose gave the best development rate and differed significantly from the classic 3-step procedure (P < 0.05).

Quantitative analysis of morphological modifications of day 6.5 horse embryos after cryopreservation: differential effects on inner cell mass and trophoblast cells

Sixteen embryos were recovered nonsurgically at day 6.5 after induced ovulation from Welsh pony mares and were evaluated for cellular changes that occur because of exposure to the cryoprotectant with or without the freeze and thaw process. Day 6.5 horse embryos were either (i) frozen and thawed using glycerol as cryoprotectant (n = 6), (ii) given only the glycerol treatment (n = 5), or (iii) washed in phosphate-buffered saline (PBS) the same number of times as in the glycerol treatment (n = 5). After treatments, embryos were incubated in Minimum Essential Medium (MEM), supplemented with BSA, glutamine, antibiotics and buffered with Hepes, for 1 h for one embryo per group and for 6 h for the others. After histological fixation, embryos were serially sectioned. On observation by light microscopy, the total numbers of interphasic, mitotic and pycnotic nuclei of each embryo were counted. Electron microscopy was used to evaluate the damage to the fine structure of intracellular organelles. The proportion of mitotic cells did not differ among groups (control: 2.3%; glycerol-treated: 1.8%; frozen-thawed: 1.3%). There were significant differences in the proportion of pycnotic cells both between control (12.8% +/- 5.6) and glycerol-treated embryos (39.4% +/- 15.9) (P < 0.05) and between control and frozen-thawed embryos (42.2% +/- 14.9) (P < 0.001), but no difference was found between treated embryos (glycerol-treated and frozen-thawed embryos). Degenerated cells were not localized in the same place in each embryo and no ultrastructural alteration was uniformly observed among every embryo of each group, but inner cell mass (ICM) cells were affected most by treatments (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)