Pregnant Rabbits Research Articles

Is the rabbit a natural model of fetal growth restriction? Morphological and functional characterization study using diffusion-weighted MRI and stereology

IntroductionRabbits are routinely used as a natural model of fetal growth restriction (FGR); however, no studies have confirmed that rabbits have FGR. This study aimed to characterize the fetoplacental unit (FPU) in healthy pregnant rabbits using diffusion-weighted MRI and stereology. A secondary objective of the study was to describe the associations among findings from diffusion-weighted MRI (DW-MRI), fetal weight measurement and histological analysis of the placenta. MethodsPregnant rabbits underwent DW-MRI under general anesthesia on embryonic day 28 of pregnancy. MR imaging was performed at 3.0 T. The apparent diffusion coefficient (ADC) values were calculated for the fetal brain, liver, and placenta. The placenta was analyzed by stereology (volume density of trophoblasts, the maternal blood space and fetal vessels). Each fetus and placenta were weighed. Two groups of fetuses were defined according to the position in the uterine horn (Cervix group versus Ovary group). ResultsWe analyzed 20 FPUs from 5 pregnant rabbits. Fetuses and placentas were significantly lighter in the Cervix group than in the Ovary group (34.7 ± 3.7 g vs. 40.2 ± 5.4 g; p = 0.02). Volume density analysis revealed that the percentage of fetal vessels, the maternal blood space and trophoblasts was not significantly affected by the position of the fetus in the uterine horn. There was no difference in ADC values according to the position of the fetus in the uterine horn, and there was no correlation between ADC values and fetal weight. DiscussionThe findings of a multimodal evaluation of the placenta in a rabbit model of FGR suggested is not a natural model of fetal growth restriction.

The Effect of Hypokinesia on the Dynamics of the Formed Elements of Blood during the Embryonic Period of Prenatal Development in Pregnant Rabbits

The erythroformula and leucoformula indicators changed in the rabbits that experienced hypokinesia during the embryonic stage of pregnancy. Compared to the rabbits that spent the pregnancy period under normal conditions, changes in concentrations of leukoformula indicators such as leukocytes, lymphocytes, monocytes, and granulocytes were detected in rabbits exposed to hypokinesia. While significant changes in erythroformula indicators: erythrocytes, average corpuscular volume of erythrocytes and hemoglobin capacity, erythrocyte sedimentation rate did not occur. The results of our studies have shown that prenatal hypokinesia causes noticeable changes in the blood coagulation system. On the other hand, changes in the coagulation system under the influence of prenatal hypokinesia were found to occur in the first periods of postnatal ontogenesis, had a continuous nature, and were maintained until the full maturity of postnatal development. Due to the effect of the hypokinesia factor, the changes in the mentioned indicators lead to the emergence of severe pathological diseases in most cases.

Differential Analysis of Cereblon Neosubstrates in Rabbit Embryos Using Targeted Proteomics

Targeted protein degradation is the selective removal of a protein of interest through hijacking intracellular protein cleanup machinery. This rapidly growing field currently relies heavily on the use of the E3 ligase cereblon (CRBN) to target proteins for degradation, including the immunomodulatory drugs (IMiDs) thalidomide, lenalidomide, and pomalidomide which work through a molecular glue mechanism of action with CRBN. While CRBN recruitment can result in degradation of a specific protein of interest (e.g., efficacy), degradation of other proteins (called CRBN neosubstrates) also occurs. Degradation of one or more of these CRBN neosubstrates is believed to play an important role in thalidomide-related developmental toxicity observed in rabbits and primates. We identified a set of 25 proteins of interest associated with CRBN-related protein homeostasis and/or embryo/fetal development. We developed a targeted assay for these proteins combining peptide immunoaffinity enrichment and high-resolution mass spectrometry and successfully applied this assay to rabbit embryo samples from pregnant rabbits dosed with three IMiDs. We confirmed previously reported in vivo decreases in neosubstrates like SALL4, as well as provided evidence of neosubstrate changes for proteins only examined in vitro previously. While there were many proteins that were similarly decreased by all three IMiDs, no compound had the exact same neosubstrate degradation profile as another. We compared our data to previous literature reports of IMiD-induced degradation and known developmental biology associations. Based on our observations, we recommend monitoring at least a major subset of these neosubstrates in a developmental test system to improve CRBN-binding compound-specific risk assessment. A strength of our assay is that it is configurable, and the target list can be readily adapted to focus on only a subset of proteins of interest or expanded to incorporate new findings as additional information about CRBN biology is discovered.

Targeted and untargeted metabolomic profiles in wild rabbit does (Oryctolagus cuniculus) of different breeding states (pregnant and lactating).

Ecological nutrition aims to unravel the extensive web of nutritional links that drives animals in their interactions with their ecological environments. Nutrition plays a key role in the success of European wild rabbit (Oryctolagus cuniculus) and could be affected by the breeding status of the animals and reflected in the metabolome of this species. As nutritional needs are considerably increased during pregnancy and lactation, the main objective of this work was to determine how the breeding status (pregnant and lactating) of European wild rabbit does affects nutritional requirements and their metabolome (using targeted and untargeted metabolomics), aiming to find a useful biomarker of breeding status and for monitoring nutritional requirements. To address this gap, 60 wild European rabbits were studied. Animals were divided according to their breeding status and only pregnant (n = 18) and lactating (n = 11) rabbit does were used (n = 29 in total). The body weight and length of each animal were analyzed. The relative and absolute chemical composition of the gastric content and whole blood sample were taken, and targeted and untargeted metabolomics were analyzed. As a main result, there were no differences in biometric measurements, gastric content, and targeted metabolomics, except for live weight and nonesterified fatty acids (NEFA), as pregnant animals showed higher live weight (+12%; p = 0.0234) and lower NEFA acid levels (-46%; p = 0.0262) than lactating females. Regarding untargeted metabolomics, a good differentiation of the metabolome of the two breeding groups was confirmed, and it was proven that pregnant animals showed higher plasmatic levels of succinic anhydride (3.48 more times; p = 0.0236), succinic acid (succinate) (3.1 more times; p = 0.0068) and propionic acid (3.98 more times; p = 0.0121) than lactating animals. However, lactating animals showed higher levels of N-[(3a,5b,7b)-7-hydroxy-24-oxo-3-(sulfoxide) cholan-24-yl]-Glycine (cholestadien) (2.4 more times; p < 0.0420), 4-maleyl-acetoacetate (MAA) (3.2 more times; p < 0.0364) and irilone (2.2 more times; p = 0.0451) than pregnant animals, any of these metabolites could be used as a potential biomarker. From these results, it can be concluded that the most notable changes were observed in the metabolome of individuals, with most of the changes observed being due to energy and protein mobilisation.

Disposition of glycolic acid into the embryo following oral administration of ethylene glycol during placentation in the rat and rabbit.

In order to evaluate the role of the placenta in the etiology of ethylene glycol (EG) developmental toxicity, the distribution of EG and its main metabolites, glycolic acid (GA) and oxalic acid (OX), into the conceptus was determined at the beginning and completion of placentation in the rat and rabbit. Two groups (n = 28) of timed-pregnant Wistar rats were administered EG (1000 mg/kg bw/day, oral gavage) from gestation day (GD) 6 to either GD 11 or GD 16; similarly, two groups (n = 28) of timed-pregnant New Zealand White rabbits were administered EG from GD 6 to either GD 10 or GD 19. Four animals from each group were sacrificed at 1, 3, 6, 9, 12, 18, or 24 h after the final administration, and maternal blood, extraembryonic fluid, and embryonic tissue were removed for analysis of EG, GA, and OX. The three analytes were predominantly cleared from all compartments in both species within 24 h. Neither EG nor OX preferentially accumulated into the conceptus compartments, compared with the maternal blood, in either species. Critically, GA was preferentially accumulated from the maternal blood only into the rat embryo at GD 11, but not at GD 16 and not into the rabbit embryo at either GD 10 or GD 19. The accumulation of GA into the rat embryo, and its decline over the course of placentation, is discussed in relation to the expression of monocarboxylate transporter isoforms across the syncytiotrophoblast.

Repeat-Dose and Embryo-Fetal Developmental Toxicity of Zinpentraxin Alfa

Zinpentraxin alfa is a recombinant human pentraxin-2 (PTX-2) developed for the treatment of various fibrotic diseases with the hypothesis that supplementing endogenous PTX-2 levels through intravenous administration should increase its regulatory capacity in circulation and at the site of disease, thereby promoting healing and reducing fibrosis. Zinpentraxin alfa has been studied in various clinical trials, particularly in patients with idiopathic pulmonary fibrosis, where it has demonstrated efficacy in slowing decline in lung function in a phase 2 study. In the present investigation, we summarize findings from 14-day repeat-dose toxicity studies in rats and cynomolgus monkeys supporting early clinical development of zinpentraxin alfa. In addition, we also describe the findings from the embryo-fetal developmental (EFD) studies conducted in rats and rabbits, since the intended fibrosis patient population may include patients of childbearing potential. Zinpentraxin alfa was well tolerated by rats and monkeys in general toxicity studies with no treatment-related adverse effects, as well as by pregnant rats over the same dose range in a definitive EFD study. In contrast, substantial toxicity was observed in a rabbit dose-range-finder EFD study. Zinpentraxin alfa was poorly tolerated by pregnant rabbits and effects on the dams correlated with post-implantation fetal losses. The disparate effects of zinpentraxin alfa on embryo-fetal development between the two species suggests a potential unknown biological function of PTX-2 in pregnancy in the rabbit, which may be relevant to humans. Our findings warrant the consideration for highly effective contraceptive measures to avoid pregnancy in patients enrolled in clinical studies with zinpentraxin alfa.

Effect of L-Carnitine Supplementation on Oxidative Stress, Metabolic and Hormonal Profile in Pregnant Rabbit Doe

Effect of L-Carnitine Supplementation on Oxidative Stress, Metabolic and Hormonal Profile in Pregnant Rabbit Doe

Effect of Golden nanoparticles and Domperidone on some hematological parameters in pregnant rabbits

The present study aims to investigate the effects of golden nanoparticles (AuNPs) alone or with the administration of the emetic drug (domperidone) on some hematological parameters of pregnant rabbits. In this study, twenty pregnant rabbits, were collected and divided into four groups (n = 5 in each group) as follows: the control group allow to drink 1 ml / kg of distilled water orally, the G1 group received an injected dose (i.m) of 150µg / kg of AuNPs, while the G2 group was treated with 300 µg /kg of the domperidone. The combined group (G3) received both AuNPs injected and domperidone orally (150µg / kg and 300 µg /kg, respectively). Blood samples were taken from each animal at (0, 15, 30 and 40) days of experimental periods to test hematological parameters (WBC count, RBC count, hemoglobin level (HGB) and Hematocrit percentage (HCT), which were calculated by using hematology analyzer. The results of the study demonstrated that there is no significant difference in WBC, RBC counts, hemoglobin, and hematocrit levels between the AuNPs and domperidone groups and the Control and G3 groups. As well as, there is no effect between periods for each group in these parameters in blood of pregnant rabbits. Thus, it is concluded that injected of AuNPs has no toxic effect on blood, as well as, the domperidone has same effect on blood.

Sustained inflation improves initial lung aeration in newborn rabbits with a diaphragmatic hernia.

Infants with a congenital diaphragmatic hernia (DH) have underdeveloped lungs and require mechanical ventilation after birth, but the optimal approach is unknown. We hypothesised that sustained inflation (SI) increases lung aeration in newborn kittens with a DH. In pregnant New Zealand white rabbits, a left-sided DH was induced in two fetal kittens per doe at 24-days gestation (term = 32 days); litter mates acted as controls. DH and control kittens were delivered by caesarean section at 30 days, intubated and mechanically ventilated (7-10 min) with either an SI followed by intermittent positive pressure ventilation (IPPV) or IPPV throughout. The rate and uniformity of lung aeration was measured using phase-contrast X-ray imaging. Lung weights in DH kittens were ~57% of controls. An SI increased the rate and uniformity of lung aeration in DH kittens, compared to IPPV, and increased dynamic lung compliance in both control and DH kittens. However, this effect of the SI was lost when ventilation changed to IPPV. While an SI improved the rate and uniformity of lung aeration in both DH and control kittens, greater consideration of the post-SI ventilation strategy is required to sustain this benefit. Compared to intermittent positive pressure ventilation (IPPV), an initial sustained inflation (SI) increased the rate and uniformity of lung aeration after birth. However, this initial benefit is rapidly lost following the switch to IPPV. The optimal approach for ventilating CDH infants at birth is unknown. While an SI improves lung aeration in immature lungs, its effect on the hypoplastic lung is unknown. This study has shown that an SI greatly improves lung aeration in the hypoplastic lung. This study will guide future studies examining whether an SI can improve lung aeration in infants with a CDH.

Results of Preclinical Animal Studies to Evaluate the Effect of Iptacopan on Pregnancy-Related Outcomes

Introduction: Iptacopan is a first-in-class, oral, selective inhibitor of factor B, a key component of the complement system alternative pathway. Inhibition of the complement system represents a potential mechanism for treatment of several complement-driven diseases including paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome. Here, we report results from the preclinical GLP toxicology studies of iptacopan on embryo-fetal development in rats and rabbits and pre- and postnatal development in rats. Methods: In the definitive embryo-fetal development studies,iptacopan was dosed orally via gavage to pregnant rats at 0, 100, 300, and 1000 mg/kg/day (N=24/group) and to pregnant rabbits at doses of 0, 100, 250, and 450 mg/kg/day (N=20/group) during the period of organogenesis (Gestation Day [GD] 6 to 17 and GD7 to 20, respectively). The progress and outcome of pregnancy were evaluated and fetuses were examined for external, visceral, and skeletal abnormalities. In a pre- and postnatal developmental toxicity study in pregnant rats, iptacopan was dosed orally via gavage at 0, 100, 300, and 1000 mg/kg/day (N=22/group) from GD6 to Lactation Day (LD) 21. The untreated offspring were allowed to mature and the effects on development, behavior, and reproductive performance were assessed. Results: In the rat embryo-fetal development study, maternal administration of iptacopan resulted in no adverse clinical observations, no effects on maternal body weights, and no adverse fetal findings. Non-adverse fetal variations of delayed ossification were observed in the skull. Two fetuses in one out of 22 litters at 1000 mg/kg/day had benign cysts on the left side of the parietal region of the head, with no impact on skeletal (skull), CNS (brain), or any other head-based structure. The no observed adverse effect level (NOAEL) for maternal toxicity and embryo-fetal development was 1000 mg/kg/day. In the definitive rabbit embryo-fetal development study, administration of iptacopan caused reduced maternal body weight gain and food consumption at 450 mg/kg/day. There were no treatment-related fetal malformations or variations. The NOAEL was 250 mg/kg/day for maternal toxicity and 450 mg/kg/day for embryo-fetal development. In the pre- and postnatal development study, no adverse findings were observed in the mated female rats during gestation, parturition, and lactation and there were no adverse effects on development of their offspring, including survival, physical development, behavior, and reproductive performance. The NOAEL for maternal (F0 generation) toxicity, maternal performance, and development of the F1 generation offspring was the highest dose of 1000 mg/kg/day. NOAEL and estimated AUC-based safety margins based on total plasma concentrations for all mentioned studies are shown in the Table. Conclusion: In nonclinical reproductive toxicity studies conducted in pregnant rats and rabbits, iptacopan was found to be generally safe with no teratogenic effects in the rat and rabbit. Estimated AUC-based safety margins were &amp;gt;5-fold for all developmental findings compared to exposure at the clinical dose of 200 mg twice daily. While these preclinical data do not provide definitive conclusions or guidance on the use of iptacopan in pregnant women, they do provide reassurance that there is no overt preclinical signal of embryo-fetal toxicity.

Erratum for Mahsoub et al., "Fetal Loss in Pregnant Rabbits Infected with Genotype 3 Hepatitis E Virus Is Associated with Altered Inflammatory Responses, Enhanced Virus Replication, and Extrahepatic Virus Dissemination with Positive Correlations with Increased Estradiol Level".

Erratum for Mahsoub et al., "Fetal Loss in Pregnant Rabbits Infected with Genotype 3 Hepatitis E Virus Is Associated with Altered Inflammatory Responses, Enhanced Virus Replication, and Extrahepatic Virus Dissemination with Positive Correlations with Increased Estradiol Level".

Whole genome sequencing characteristics of Chlamydia psittaci caprine AMK-16 strain, a promising killed whole cell veterinary vaccine candidate against chlamydia infection.

Chlamydia psittaci is a primary zoonotic pathogen with a broad host range causing severe respiratory and reproductive system infection in animals and humans. To reduce the global burden of C. psittaci-associated diseases on animal welfare and health and to control the pathogen spread in husbandry, effective vaccines based on promising vaccine candidate(s) are required. Recently, the caprine C. psittaci AMK-16 strain (AMK-16) demonstrated a high level of protection (up to 80-100%) in outbred mice and pregnant rabbits immunized with these formaldehyde-inactivated bacteria against experimental chlamydial wild-type infection. This study investigated the molecular characteristics of AMK-16 by whole-genome sequencing followed by molecular typing, phylogenetic analysis and detection of main immunodominant protein(s) eliciting the immune response in mouse model. Similarly to other C. psittaci, AMK-16 harbored an extrachromosomal plasmid. The whole-genome phylogenetic analysis proved that AMK-16 strain belonging to ST28 clustered with only C. psittaci but not with Chlamydia abortus strains. However, AMK-16 possessed the insert which resulted from the recombination event as the additional single chromosome region of a 23,100 bp size with higher homology to C. abortus (98.38-99.94%) rather than to C. psittaci (92.06-92.55%). At least six of 16 CDSs were absent in AMK-16 plasticity zone and 41 CDSs in other loci compared with the reference C. psittaci 6BC strain. Two SNPs identified in the AMK-16 ompA sequence resulted in MOMP polymorphism followed by the formation of a novel genotype/subtype including three other C. psittaci strains else. AMK-16 MOMP provided marked specific cellular and humoral immune response in 100% of mice immunized with the inactivated AMK-16 bacteria. Both DnaK and GrpE encoded by the recombination region genes were less immunoreactive, inducing only a negligible T-cell murine immune response, while homologous antibodies could be detected in 50% and 30% of immunized mice, respectively. Thus, AMK-16 could be a promising vaccine candidate for the development of a killed whole cell vaccine against chlamydiosis in livestock.

Analysis of Russian and foreign research on rabbits feeding (review)

Rabbit farming being a well-developed and highly profi table area of livestock farming is one of the indicators of the state of economic development of the country. In Russia despite the fact that 78,5 % of rabbit meat is produced on household farms industrial rabbit breeding is gaining momentum. The basis of any area of animal husbandry is the organization of feeding, since feeding costs account for 60–70 % of the cost of production, and more than 90 % of animal diseases are associated with errors in their feeding. At the end of 2020 rabbit meat production in Russia amounted to 19,6 thousand tons. Total for the period 2016–2020 rabbit meat production increased by 8 %. Scientists from different countries pay special attention to studying the nutritional and energy needs of replacement young animals, pregnant and lactating doe rabbits, since the reproduction process and the volume of production depend on them. The results of scientifi c research on feeding doe rabbits during the reproductive period with complete granulated feed with diff erent ratios of nutrients and energy have been analyzed in the review. The authors note that the content of digestible energy and protein in the diets used to feed pregnant doe rabbits in Russian and foreign studies are the same, while the fiber content differs significantly. Since researchers around the world are concerned about the same problems of optimizing the feeding of doe rabbits, a joint discussion of research results especially by scientists belonging to different scientific schools opens up new horizons for achieving purposes and practical use of the new knowledge obtained.

Early treatment with Fibrinogen γ-chain peptide-coated, ADP-encapsulated Liposomes (H12-(ADP)-liposomes) ameliorates post-partum hemorrhage with coagulopathy caused by amniotic fluid embolism in rabbits

Amniotic fluid embolism is an unpredictable and sometimes lethal complication of childbirth. Fibrinogen γ-chain peptide-coated, ADP-encapsulated Liposomes (H12-(ADP)-liposomes), which were developed as a platelet substitute, may be useful to control postpartum hemorrhage with consumptive coagulopathy. This study aimed to establish a hemodynamically stable amniotic fluid embolism animal model and evaluate the efficacy of H12-ADP-liposome infusion in the initial management of postpartum hemorrhage complicated with amniotic fluid embolism-involved coagulopathy. Pregnant New Zealand white rabbits (28th day of pregnancy or normal gestation period of 29-35 days) underwent cesarean delivery, followed by intravenous administration of amniotic fluid (a total of 3.0 mL administered in 4 doses over 9 minutes). Thereafter, uncontrolled postpartum hemorrhage was induced by transecting the right midartery and concomitant vein in the myometrium. After initial bleeding for 5 minutes, rabbits received isovolemic fluid resuscitation through the femoral vein with an equivalent volume of blood loss every 5 minutes for 60 minutes. The transfusion regimens included platelet-rich plasma, platelet-poor plasma, and a bolus administration of H12-ADP-liposomes followed by platelet-poor plasma transfusion (8 rabbits per group). Moreover, 60 minutes after initiation of bleeding, rabbits received surgical hemostasis by ligation of bleeding vessels, except in cases with spontaneous hemostasis. The administration of amniotic fluid caused thrombocytopenia (56±3 × 103/μL) and prolonged both clotting time (before administration: 130.0±3.0 to 171.0±5.0 seconds) and prothrombin time (4.5±0.1 to 4.7±0.1 seconds). After the initial 5-minute bleeding in the rabbits, the mean arterial pressure fell to 43±2 mm Hg. Platelet-poor plasma transfusion alone further prolonged clotting time and prothrombin time at 60 minutes (192.0±10.0 and 5.2±0.1 seconds, respectively) with decreasing mean arterial pressure to <40 mm Hg. By contrast, the administration of H12-ADP-liposomes followed by platelet-poor plasma transfusion reduced the prolonged clotting time (153.0±5.0 seconds) and prothrombin time (4.9±0.1 seconds) similar to platelet-rich plasma transfusion (154.0±11.0 and 4.9±0.1 seconds, respectively) at 60 minutes. These rabbits maintained a mean arterial pressure of >45 mm Hg throughout the experiment. H12-ADP-liposome infusion and platelet-poor plasma transfusion and platelet-rich plasma transfusion yielded spontaneous hemostasis in 4 of 8 rabbits, whereas platelet-poor plasma transfusion did not stop bleeding in any of the rabbits. The total blood loss was 59±17 mL in the H12-ADP-liposomes and platelet-poor plasma group, which was half of that in the platelet-poor plasma group (124±10 mL). H12-ADP-liposome infusion may be effective in the initial management of postpartum hemorrhage complicated with amniotic fluid embolism, resulting in mitigation of consumptive coagulopathy.

Selenium Injection in Dam Rabbits During Gestation Has Important Effects on Progeny Productive Performance.

Micromineral elements have a fundamental participation in the processes of organogenesis and fetal development. The objective of this study was to assess the effect of selenium (Se) injection in pregnant female rabbits, during organogenesis or rapid fetal growth, on the productive performance of their progeny. An experiment was carried out with 30 New Zealand female rabbits, with an average age of 6 months. At the end of mating (day 0), using a randomized complete design, the female rabbits were distributed into three experimental groups, which were assigned to the following treatments: Control, female rabbits were injected intramuscularly (IM) with 0.5 ml of saline on days 13 and 23 of gestation; Early administration, female rabbits that were injected IM with Se (0.10 mg/kg BW) on day 13 of gestation (organogenesis) and 0.5 ml of saline on day 23 of gestation; and Late administration, female rabbits that were injected IM with 0.5 ml of saline on day 13 of gestation and Se (0.10 mg/kg BW) on day 23 of gestation (rapid fetal growth). No differences were found on kindling performance of dams and pre-weaning growth of rabbit offspring. However, an injection of Se to pregnant rabbits affected the growth and development of their progeny, with the treatment leading to changes in the yield of some carcass traits (forelimb weight and forelimb muscle weight) and weights of some organs (liver, lungs, and spleen). The Se treatment (both early and late) also resulted in lower concentrations of glucose, triglycerides, and cholesterol when compared to the control group. These effects were different when Se injection was performed during organogenesis or rapid fetal development. The results from this study suggest that there are beneficial effects of gestational Se injection of rabbit dams on important productive traits of their progeny.

Untargeted metabolomics study of dexamethasone-induced congenital cleft palate in New Zealand rabbits

Objective: To investigate the metabolic disorders in placental tissues of dexamethasone induced cleft palate mode. Methods: Twelve pregnant rabbits were randomly divided into dexamethasone group (experimental group, 8) and saline control group (4), and a certain amount of dexamethasone and saline were administered intramuscularly to the experimental and control groups respectively from embryonic days (ED) 13 to 16, and placental tissue samples were collected on day 21 of gestation. The corresponding profiles of the embryonic placental tissue samples were obtained by liquid chromatography-triple tandem quadrupole(LC-MS), and the metabolites of the embryonic placental tissues were characterized by principal component analysis among the dexamethasone-treated group with cleft palate (D-CP group), the dexamethasone-treated group without cleft palate (D-NCP group) and the control group. Results: There were significant metabolic differences among the D-CP group, D-NCP group and control group, with a total of 133 differential metabolites (VIP>1, P<0.05) involving in important metabolic pathways including vitamin B6 metabolism, lysine metabolism, arginine anabolic metabolism, and galactose metabolism. The four metabolites, vitamin B6, galactose, lysine and urea, differed among the three groups (P<0.05). There were significant differences in vitamin B6 (0.960±0.249, 0.856±0.368, 1.319±0.322), galactose (0.888±0.171, 1.033±0.182, 1.127±0.127), lysine (1.551±0.924, 1.789±1.435, 0.541±0.424) and urea (0.743±0.142, 1.137±0.301, 1.171±0.457, respectively) levels among control group, D-NCP group and D-CP group (F=5.90, P=0.008; F=5.59, P=0.009; F=4.26, P=0.025; F=5.29, P=0.012). Conclusions: The results indicated that dexamethasone induced cleft palate may be highly correlated with metabolic disorders including vitamin B6 metabolism, lysine metabolism, arginine anabolic metabolism and galactose metabolism.

Значение РСК и ПЦР в диагностике экспериментальной инфекции кроликов, вызванной Chlamydia psittaci

Specific antibodies against сhlamydia were detected using complement fixation test and сhlamydia genome was detected using polymerase chain reaction in pregnant rabbits experimentally infected with Chlamydia psittaci. The infected rabbits developed a fever and respiratory signs and the infection was confirmed by specific antibodies against сhlamydia detected in their blood and by abnormalities in rabbit kindling. Complement fixation test of paired rabbit sera revealed an increase in the titers of specific antibodies against сhlamydia, which on Day 7 post infection varied within 1:7.5; on Day 14, mean concentration was 1:40 and by Day 30 mean titer increased to 1:60. However, when pathological materials from the urogenital tract of the experimental animals were tested in polymerase chain reaction and in smear microscopy, it was impossible to confirm that there is an etiological link between сhlamydia and kindling problems in experimental animals. At the same time, molecular and genetic tests of internal organs (liver) sampled from stillborn baby rabbits revealed the сhlamydia genome, thus, proving сhlamydia involvement into the pathological kindling. Therefore, such a retrospective method as complement fixation test with a сhlamydia antigen is of high diagnostic value for lifetime сhlamydia diagnosis.

Differential expression of lipid metabolic genes in hypercholesterolemic rabbit placenta predisposes the offspring to develop atherosclerosis in early adulthood

AimsMaternal hypercholesterolemia (MHC) is a pathological condition that may cause atherosclerosis in the adulthood of the offspring. The study aims to identify the role of in-utero programming by the placenta in atherogenesis and associated liver pathology in offspring. Main methodsFemale New Zealand white rabbits with normal lipid profiles were fed a 0.3 % HFD after mating. Lipid levels were monitored, and pregnant rabbits were sacrificed at the end of trimester 1, trimester 2, and trimester 3. Placental histology and expression of lipid metabolism genes were studied. Lipid levels, aortic lesions, and mRNA expression of cholesterol synthesis genes were investigated in fetuses at the end of gestation. A group of fetuses was allowed to attain early adulthood to investigate the liver lipid metabolism and atherogenesis with and without an HFD. Key findingsElevated maternal lipid levels and placental gene expression were differentially modulated in HFD-fed mothers. HFD-fed rabbits demonstrated differential expression of the placental genes involved in receptor-mediated endocytosis of cholesterol, lipogenesis, and lipolysis in all three trimesters. It resulted in significant lipid depositions in the placenta, hyperlipidemia, and a decrease in hepatic cholesterol synthesis in fetuses at the end of gestation. There was no atherogenesis in the aorta of offspring at trimester 3, but such offspring of HFD-fed mothers developed atherosclerosis and non-alcoholic fatty liver (NAFL) with profound steatosis in their early adulthood with and without HFD. SignificanceDiet-induced MHC differentially expressed placental lipid genes that may program the offspring to develop atherosclerosis and associated NAFL in early adulthood.

A Study of Embryotoxic, Foetotoxic, and Teratogenic Effects of the Original Antituberculosis Agent Thiozonide in Pregnant Rabbits

Several treatment regimens with antituberculosis medicinal products are available for tuberculosis. Thiozonide is a newly developed original antimicrobial agent that exhibits bacteriostatic activity against Mycobacterium tuberculosis strains H37Rv, CN-37, CN-40, and MS-115.The aim of the study was to investigate the embryotoxic, foetotoxic, and teratogenic effects of thiozonide in pregnant rabbits.Materials and methods. The study involved 66 pregnant rabbits (4 groups of 16–17 animals each). The rabbits received oral thiozonide from day 6 to day 19 of gestation at doses of 20.6 mg/kg (1 TD (therapeutic dose)), 103 mg/kg (5 TDs), and 206 mg/kg (10 TDs). The control group received a 1% starch solution. The authors conducted a macroscopic examination of the reproductive organs and a histological evaluation of the placenta in eutha nised pregnant rabbits. Live foetuses underwent a check for developmental abnormalities, a skeletal development evaluation with a modified Dawson’s method, and a histologic examination of the internal organs.Results. The study showed no clinical signs of toxicity and no mortality associated with thiozonide in pregnant rabbits across all dose groups. Macroscopic and histological examinations revealed no pathological changes in the reproductive organs of pregnant rabbits. The evaluation of embryotoxic and foetotoxic effects did not identify any differences between the foetuses of the animals assigned to different doses of thiozonide and the control group. The authors found no developmental abnormalities in the foetuses. Examinations of foetal skeleton development and internal organ condition identified no differences between the groups and no abnormalities. The authors registered the death of all foetuses (late resorption) in one rabbit from the 206 mg/kg group. Therefore, the 103 mg/kg dose (5 TDs) was selected as a reasonable No Observed Adverse Effect Level (NOAEL).Conclusions. Thiozonide has no embryotoxic, foetotoxic, or teratogenic effects.

Placental-fetal distribution of carbon particles in a pregnant rabbit model after repeated exposure to diluted diesel engine exhaust

BackgroundAirborne pollution particles have been shown to translocate from the mother’s lung to the fetal circulation, but their distribution and internal placental-fetal tissue load remain poorly explored. Here, we investigated the placental-fetal load and distribution of diesel engine exhaust particles during gestation under controlled exposure conditions using a pregnant rabbit model. Pregnant dams were exposed by nose-only inhalation to either clean air (controls) or diluted and filtered diesel engine exhaust (1 mg/m3) for 2 h/day, 5 days/week, from gestational day (GD) 3 to GD27. At GD28, placental and fetal tissues (i.e., heart, kidney, liver, lung and gonads) were collected for biometry and to study the presence of carbon particles (CPs) using white light generation by carbonaceous particles under femtosecond pulsed laser illumination.ResultsCPs were detected in the placenta, fetal heart, kidney, liver, lung and gonads in significantly higher amounts in exposed rabbits compared with controls. Through multiple factor analysis, we were able to discriminate the diesel engine exposed pregnant rabbits from the control group taking all variables related to fetoplacental biometry and CP load into consideration. Our findings did not reveal a sex effect, yet a potential interaction effect might be present between exposure and fetal sex.ConclusionsThe results confirmed the translocation of maternally inhaled CPs from diesel engine exhaust to the placenta which could be detected in fetal organs during late-stage pregnancy. The exposed can be clearly discriminated from the control group with respect to fetoplacental biometry and CP load. The differential particle load in the fetal organs may contribute to the effects on fetoplacental biometry and to the malprogramming of the fetal phenotype with long-term effects later in life.