Reproductive Toxicity Studies Research Articles

Perinatal exposure to the immune-suppressant di-n-octyltin dichloride affects brain development in rats

Disruption of the immune system during embryonic brain development by environmental chemicals was proposed as a possible cause of neurodevelopmental disorders. We previously found adverse effects of di-n-octyltin dichloride (DOTC) on maternal and developing immune systems of rats in an extended one-generation reproductive toxicity study according to the OECD 443 test guideline. We hypothesize that the DOTC-induced changes in the immune system can affect neurodevelopment. Therefore, we used in-vivo MRI and PET imaging and genomics, in addition to behavioral testing and neuropathology as proposed in OECD test guideline 443, to investigate the effect of DOTC on structural and functional brain development. Male rats were exposed to DOTC (0, 3, 10, or 30 mg/kg of diet) from 2 weeks prior to mating of the F0-generation until sacrifice of F1-animals. The brains of rats, exposed to DOTC showed a transiently enlarged volume of specific brain regions (MRI), altered specific gravity, and transient hyper-metabolism ([18F]FDG PET). The alterations in brain development concurred with hyper-responsiveness in auditory startle response and slight hyperactivity in young adult animals. Genomics identified altered transcription of key regulators involved in neurodevelopment and neural function (e.g. Nrgrn, Shank3, Igf1r, Cck, Apba2, Foxp2); and regulators involved in cell size, cell proliferation, and organ development, especially immune system development and functioning (e.g. LOC679869, Itga11, Arhgap5, Cd47, Dlg1, Gas6, Cml5, Mef2c). The results suggest the involvement of immunotoxicity in the impairment of the nervous system by DOTC and support the hypothesis of a close connection between the immune and nervous systems in brain development.

Preclinical Safety Assessment of Gadopiclenol: A High-Relaxivity Macrocyclic Gadolinium-Based MRI Contrast Agent.

Gadopiclenol is a new high-relaxivity macrocyclic gadolinium-based contrast agent for magnetic resonance imaging of the central nervous system and other body regions. The product has been approved by US Food and Drug Administration and is currently being evaluated by European Medicines Agency. For risk assessment of the single diagnostic use in humans, the safety profile of gadopiclenol was evaluated with a series of preclinical studies. With exception of dose-ranging studies, all safety pharmacology and toxicology studies were performed in compliance with Good Laboratory Practice principles. Safety pharmacology studies were conducted to assess potential effects on cardiovascular (in vitro and in dogs), respiratory (in rats and guinea pigs), neurological (in rats), and renal endpoints (in rats). Toxicology studies were also performed to investigate acute toxicity (in rats and mice), extended single-dose (in rats and dogs) and repeated-dose toxicity (in rats and dogs), reproductive (in rats), developmental (in rats and rabbits) and juvenile toxicity (in rats), as well as genotoxicity (in vitro and in rats), local tolerance (in rabbits), potential immediate hypersensitivity (in guinea pigs), and potential tissue retention of gadolinium (in rats). Safety pharmacology studies conducted at high intravenous (IV) doses showed a satisfactory tolerance of gadopiclenol in the main body systems. After either single or repeated IV dosing (14 and 28 days) in rats and dogs, gadopiclenol was well tolerated even at high doses. The no-observed-adverse-effect level values (ie, the highest experimental dose without adverse effects) representing between 8 times in rats and 44 times in dogs (based on the exposure), the exposure achieved in humans at the intended diagnostic dose, provide a high safety margin. No or only minor and reversible effects on body weight, food consumption, clinical signs, clinical pathology parameters, or histology were observed at the highest doses. The main histological finding consists in renal tubular vacuolations (exacerbated after repeated exposure), which supports a well-known finding for this class of compounds that has no physiological consequence on kidney function. Reproductive toxicity studies showed no evidence of effects on reproductive performance, fertility, perinatal and postnatal development in rats, or reproductive development in rats or rabbits. The safety profile of gadopiclenol in juvenile rats was satisfactory like in adults. Gadopiclenol was not genotoxic in vitro in the Ames test, a mouse lymphoma assay, and a rat in vivo micronucleus test. There were no signs of local intolerance at the injection site after IV and intra-arterial administration in rabbits. However, because of minor signs of intolerance after perivenous administration, misadministration must be avoided. Gadopiclenol exhibited no signs of potential to induce immediate hypersensitivity in guinea pigs. High safety margins were observed between the single diagnostic dose of 0.05 mmol/kg in humans and the doses showing effects in animal studies. Gadopiclenol is, therefore, well tolerated in various species (mice, rats, dogs, rabbits, and guinea pigs). All observed preclinical data support the clinical approval.

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 >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.

Is there any added value of the second generation in the Extended One-Generation Reproductive Toxicity Study (EOGRTS)? A retrospective analysis of 24 EOGRTS

The Extended One-Generation Reproductive Toxicity Study (EOGRTS) is a standard information requirement under Registration, Evaluation, Authorization and restriction of Chemicals (REACH) in Europe. Inclusion of an F2 generation is considered useful if this impacts hazard identification or when it provides additional information altering the reproductive or developmental No Observed Adverse Effect Level (NOAEL) and subsequent risk assessment. In this retrospective analysis the added value of the F2 generation in 24 EOGRTS was evaluated. Our retrospective analysis showed an added value of the second generation in 1/24 EOGRTS only, where extending with the F2 generation lowered both the reproductive and developmental NOAEL. For this substance, extension with the F2 generation led to classification for effects on fertility. Hazard identification for developmental effects was not impacted based on clear developmental toxic effects already observed in the F1 generation and in previous studies with this substance. Risk assessment may be impacted if the developmental toxic effects are the most critical effects observed for this substance. For 23/24 studies included in this retrospective analysis, hazard and risk assessment were unaffected by inclusion of the F2 generation. Moreover, for 13/13 studies with external triggers for inclusion of the F2 generation hazard and risk assessment were unaffected. By decreasing the number of EOGRTS that are extended with an F2 generation, the number of animals used in regulatory developmental and reproductive toxicity studies may be significantly reduced in the future without negatively affecting the ability to identify potentially harmful chemicals.

Combined reproductive and developmental toxicity study of pesticide abamectin on male and female Wistar Hannover rats

Abamectin is a widely used pesticide and anthelmintic for humans and animals. Previous toxicological studies showed evidence of adverse effects on reproduction, but the findings were inconclusive. Abamectin is known to exhibit teratogenic activity, causing different malformations during developmental stages in rats and rabbits. The present work aims at combining reproductive and developmental toxicological assessments in a single study to evaluate the impact of abamectin on reproductive, fertility, and developmental functions. Abamectin was administered orally to 20 male and 20 female rats at doses of 0, 0.1, 1.0, and 2.0 mg/kg body weight. Abamectin exposure was prolonged for 11 weeks for males and 10 weeks for females before mating. Females were also treated during mating and pregnancy. In this study, treated animals were mated with untreated intact animals to further assess the potential sex sensitivity effect. The results demonstrate that male rats were more susceptible to general toxic effects such as decreased body weight and showed a more toxic effect on reproductive function and fertility at doses of 1.0 and 2.0 mg/kg/day. Furthermore, stages of gametogenesis and early fetal development are the most vulnerable of the reproductive process to endocrine disruptors' action, leading to changes in the estrous cycle in females and sperm quality in males. Abamectin can produce developmental toxicity in rats at a dose of 2 mg/kg/day, which is not a maternally toxic dose. Accordingly, NOAEL for reproductive toxicity and developmental toxicity with fetotoxic effects were established at the dose level of 0.1 mg/kg/day and 1.0 mg/kg/day, respectively.

A battery of in silico models application for pesticides exerting reproductive health effects: Assessment of performance and prioritization of mechanistic studies

Given the high attention to endocrine disrupting chemicals (EDC), there is an urgent need for the development of rapid and reliable approaches for the screening of large numbers of chemicals with respect to their endocrine disruption potential. This study aimed at the assessment of the correlation between the predicted results of a battery of in silico tools and the reported observed adverse effects from in vivo reproductive toxicity studies. We used VirtualToxLab (VTL) software and the EndocrineDisruptome (ED) online tool to evaluate the binding affinities to nuclear receptors of 17 pesticides, 7 of which were classified as reprotoxic substances under Regulation (EC) No 1272/2008 on the classification, labelling and packaging of substances and mixtures (CLP). Then, we aligned the results of the in silico modelling with data from ToxCast assays and in vivo reproductive toxicity studies. We combined results from different in silico tools in two different ways to improve the characteristics of their predictive performance. Reproductive toxicity can be caused by various mechanisms; however, in this study, we demonstrated that the use of a battery of in silico tools for assessing the binding to nuclear receptors can be useful for identifying hazardous compounds and for prioritizing further studies.

Использование кроликов в доклинических исследованиях

Rabbits are one of the most commonly used laboratory animal species in biomedical research. A large number of models of various human diseases have been developed on rabbits. Rabbits are widely used to assess the safety of substances and pharmaceuticals. The development of genetically modified rabbits has expanded their use for modeling various pathological conditions. Advantages of the rabbit include its relatively small size and relative ease of housing. Practically any experimental manipulations can be carried out on rabbits (any methods of administering the tested compounds are available, conducting various instrumental studies, multiple collection of blood samples, etc. is possible). In studies of reproductive toxicity, an important advantage of the rabbit relative to larger animals is a short gestation period, good reproductive ability. Rabbits are sensitive to human teratogens and are the preferred non-rodent species for embryofetal development studies. Rabbits are used in immunology for the production of diagnostic antibodies. An important point is that the scientific literature provides a sufficient amount of historical and reference materials on the anatomy, physiology, and pathophysiology of these animals. The disadvantages of rabbits include frequently developed disorders of the gastrointestinal tract. The functional activity of the rabbit’s digestive system is highly dependent on the diet. Changes in the diet should be done gradually. Rabbits need to be able to exercise daily. With the wrong manipulation technique, it is easy to cause injury to the rabbit. Since some diseases may spontaneously develop in laboratory rabbits, this may require either the use of therapy or the exclusion of the animal from the experiment. Therefore, in the case of planning long-term studies on rabbits, it is reasonable to include at least 8 males and 8 females in each group. If recovery groups are needed, the number of animals should be sufficient to evaluate possible long-term effects. When planning and conducting experiments, every effort should be made to implement the principles of 3Rs. Combination designs with pharmacological safety, immunotoxicity, reproductive toxicity, pharmacokinetics, and toxicokinetics studies as part of a toxicity study may help to reduce the number of rabbits in toxicological research. Studies should be designed taking into account the available scientific data on the test compound or on analogue compounds, on the basis of which scientific-based decision can be made to reduce the number of animals in the experiment without compromising the human safety.

Референтные интервалы в репродуктивной токсичности крыс Вистар

The need to risk assessment of reproductive and ontogenetic toxicity of a medicine depends on a number of factors such as the properties of the drug, indications for use and the target patient population. It should be noted that this type of research is widespread. To increase the reliability of the of research data interpretation, the evaluation of the results should include not only comparison with control values, but also with reference values obtained in the same test center. The purpose of the study was the creation of reference intervals for the main indicators evaluated in studies of developmental and reproductive toxicity for Wistar rats. To calculate the reference intervals, the data obtained in the course of research at RMC “HOME OF PHARMACY” in the period from 2015 to 2021. Animals of the control groups were used to calculate the reference intervals. All manipulations and experiments are approved by the bioethical commission. Prenatal development was assessed by indicators: the number of live and dead fetuses, corpus luteum, implantation sites, pre- and post-implantation death was calculated. In the postnatal period, body weight was measured weekly in rat pups, a number of physiological parameters and the rate of maturation of sensory-motor reflexes were evaluated. For the data, a nonparametric method for determining reference intervals was applied. The most variable indicators are the number of implantation sites, the percentage of pre- and post-implantation death and the time of testicular descent, which must be taken into account when analyzing the data obtained. It is shown that the values of reference intervals obtained by us are generally comparable with the literature data.

S03-01: The design and conduct of Extended One-Generation Reproductive Toxicity studies (EOGRTS)

S03-01: The design and conduct of Extended One-Generation Reproductive Toxicity studies (EOGRTS)

P08-15: Practical consequences of ECHA's advice on dose level selection for reproductive toxicity studies

P08-15: Practical consequences of ECHA's advice on dose level selection for reproductive toxicity studies

S03-02: Extended One-Generation Reproductive Toxicity study (EOGRTS) in the EU regulatory context

S03-02: Extended One-Generation Reproductive Toxicity study (EOGRTS) in the EU regulatory context

Developmental and reproductive safety of Advax-CpG55.2™ adjuvanted COVID-19 and influenza vaccines in mice

SpikoGen® is a recombinant spike protein vaccine against COVID-19 that obtained marketing authorization in the Middle East on October 6th, 2021, becoming the first adjuvanted protein-based COVID-19 vaccine of its type to achieve approval. SpikoGen® vaccine utilizes a unique adjuvant Advax-CpG55.2, which comprises delta inulin and CpG55.2 oligonucleotide, a synthetic human toll-like receptor (TLR)-9 agonist. As part of a safety assessment, developmental and reproductive toxicity (DART) studies were undertaken in mice of Advax-CpG55.2 adjuvanted formulations including SpikoGen®, a H7 hemagglutinin influenza vaccine (rH7HA), the bivalent combination of SpikoGen® and rH7HA, and a next-generation quadrivalent spike protein vaccine. In the first study, vaccines were administered intramuscularly to pregnant dams on gestation days (GD) 6.5 and 12.5, and in the second two doses were given in the pre-mating period with a further two doses during gestation. The doses used in the pregnant mice were 250–1000 times the usual human doses on a weight for weight basis. Strong serum antibody responses with neutralizing activity against the relevant virus were seen in the immunized dams and also at the time of weaning in the sera of their pups, consistent with robust maternal antibody transfer. No adverse effects of any of the vaccine formulations were observed in the immunized dams or their pups. Notably, there were no adverse effects of any of the Advax-CpG55.2 adjuvanted vaccines on female mating performance, fertility, ovarian or uterine parameters, embryo-fetal or postnatal survival, fetal growth, or neurofunctional development. No evidence of antigen interference was observed when SpikoGen® vaccine was mixed and co-administered with influenza hemagglutinin vaccine to pregnant dams. Together with the strong safety profile of SpikoGen® vaccine seen in adults and children in human trials, this DART study data supports the safety of Advax-CpG55.2 adjuvanted COVID-19 and influenza vaccine in women of childbearing potential including during pregnancy.

Extended exposure to tetrabromobisphenol A-bis(2,3-dibromopropyl ether) leads to subfertility in male mice at the late reproductive age.

Tetrabromobisphenol A-bis(2,3-dibromopropyl ether) (TBBPA-BDBPE), a commonly used brominated flame retardant as a decabromodiphenyl ether substitute, has been detected in various environmental compartments, but its health hazards remain largely unknown. Our recent study showed that low-dose exposure of male mice to TBBPA-BDBPE from postnatal day (PND) 0 to 56 caused remarkable damage to the microtubule skeleton in Sertoli cells and the blood-testis barrier (BTB) but exerted little effect on conventional reproductive endpoints in adulthood. To investigate whether TBBPA-BDBPE may cause severe reproductive impairments at late reproductive age, here, we extended exposure of historically administrated male mice to 8-month age and allowed them to mate with non-treated females for the evaluation of fertility, followed by a general examination for the reproductive system. As expected, we found that 8-month exposure to 50 μg/kg/d as well as 1000 μg/kg/d TBBPA-BDBPE caused severe damage to the reproductive system, including reduced sperm counts, increased sperm abnormality, histological alterations of testes. Moreover, microtubule damage and BTB-related impairment were still observed following 8-month exposure. Noticeably, high-dose TBBPA-BDBPE-treated mice had fewer offspring with a female-biased sex ratio. All results show that long-term exposure to TBBPA-BDBPE caused severe reproductive impairment, including poor fertility at late reproductive age. It is therefore concluded that slight testicular injuries in early life can contribute to reproductive impairment at late reproductive age, highlighting that alterations in certain non-conventional endpoints should be noticed as well as conventional endpoints in future reproductive toxicity studies.

Extended one-generation reproductive toxicity study evaluating gardenia blue in Sprague Dawley rats

Gardenia blue powder was administered at 0.5%, 2.5%, or 5.0% in feed to male and female Sprague Dawley rats in an Extended One-Generation Reproductive Toxicity Study (OECD Test Guideline 443). The dosed diet began 14 days before mating and was continued at the same concentration level for the entire study for all parental animals (P0) and offspring (F1). At weaning, offspring were allocated into one of 5 cohorts for different endpoints. P0 and F1 animals had blue urine, blue or black feces, and blue discolorations in gastrointestinal organs, mesenteric lymph nodes, and kidneys. This treatment-related finding was not considered adverse as there were no histopathologic correlates. There was a dose-related increase in sperm concentration in P0 and F1 males. There were dose-related increases in heart weights of F1 postnatal day (PND) 21 males, male and female thyroid weights, and female TSH levels of PND 91 F1 offspring, with no histopathological correlate. There were no consistent treatment-related adverse effects on any other parameters evaluated for general toxicity, reproductive toxicity, developmental neurotoxicity, or developmental immunotoxicity. The highest dietary concentration (5.0%) of gardenia blue powder was the no observed adverse effect level (NOAEL) for male and female rats at all life stages evaluated.

Evaluating H295R steroidogenesis assay data for robust interpretation

The in vitro H295R steroidogenesis assay (OECD TG 456) is used to determine a chemical's potential to interfere with steroid hormone synthesis/metabolism. As positive outcomes in this assay can trigger significant higher tiered testing, we compiled a stakeholder database of reference and test item H295R data to characterize assay outcomes. Information concerning whether a Level 5 reproductive toxicity study was triggered due to a positive outcome in the H295R assay was also included.Quality control acceptance criteria were not always achieved, suggesting this assay is challenging to conduct within the guideline specifications. Analysis of test item data demonstrated that pairwise significance testing to controls allowed for overly sensitive statistically significant positive outcomes, which likely contribute to the assay's high positive hit rate. Complementary interpretation criteria (e.g., 1.5-fold change threshold) markedly reduced the rate of equivocal and positive outcomes thus improving identification of robust positive effects in the assay.Finally, a case study (positive H295R outcome and no endocrine adversity in vivo) is presented, which suggests that stricter data interpretation criteria could refine necessary in vivo follow-up testing. Overall, the described additional criteria could improve H295R data interpretation and help inform on how to best leverage this assay for regulatory purposes.

Effects of moringa stenopetala (Baker f.) Cufod leaf on reproductive organs and serum biochemical levels in male rats: An in vivo reproductive toxicity study

BackgroundMoringa stenopetala (Baker f.) Cufod. (Moringaceae) leaves are a common food source and traditional medicine used to treat a variety of illnesses, including malaria, hypertension, stomach discomfort, diabetes, elevated cholesterol, and the removal of the retained placenta. Its reproductive toxicity studies are limited. Therefore, the objective of the current study was to examine the toxicity of a 70% ethanol extract of Moringa stenopetala leaf on the reproductive organs and serum biochemical levels in male Wistar rats. MethodFresh leaves of Moringa stenopetala were extracted using 70% ethanol. For this study, five groups of animals, each containing twenty rats, were used. Groups I - III were treated with 250, 500, and 1000 mg/kg body weight of Moringa stenopetala leaf extract, respectively. Groups IV and V were pair-fed and ad libitum control groups. The extract was given for ten weeks. Data about body weights, weights and histology of reproductive organs, testosterone, LH, and FSH, levels, and serum chemistry were analyzed using one-way ANOVA, Tukey's test, and Dunnett's test. ResultsCompared to the pair-fed control group, the sex hormones like testosterone, FSH, and LH levels increased in the 1000 mg/kg body weight treated rats. Significant differences were not seen in the weight and histology of the testis, epididymis, prostate gland, or seminal glands. However, the serum ALT, AST, ALP, HDL, and creatinine levels were significantly raised in the high-dose-treated group. ConclusionMoringa stenopetala may increase reproductive hormones in male rats. Consuming Moringa stenopetala leaves could therefore help to increase male reproduction.

Sodium molybdate dihydrate does not exhibit developmental or reproductive toxicity in Sprague-Dawley rats maintained on a marginal copper diet

Groups of 24 weanling female Sprague-Dawley rats were administered molybdenum (Mo) as sodium molybdate dihydrate (SMD) in drinking water at target dose levels of 0, 20, or 40 mg Mo/kg bw/day and fed a semi-purified marginal copper (6.2 ppm Cu) AIN-93 G diet for 8 weeks prior to mating, through cohabitation and pregnancy until Gestation Day 21. The objective was to confirm the reproductive and developmental effects of SMD reported by Fungwe et al. (1990) at estimated doses as low as 1.5 mg Mo/kg bw/day in a similarly designed study with marginal Cu diet (6.3 ppm). There were no test material-related effects at 20 or 40 mg Mo/kg bw/day on mortality, clinical observations, body weight, body weight gain, food consumption, estrous cycling, reproductive performance, maternal macroscopic pathology, ovarian or uterine parameters, litter size, resorptions, fetal sex ratio, fetal weight, or external fetal malformations or variations. Water consumption was increased compared to controls at both dose levels during the pre-mating and gestation periods, with no apparent adverse impact. There was no evidence of copper depletion in serum at any dose level. In conclusion, the no-observed-adverse-effect levels (NOAELs) for systemic, maternal reproductive, and developmental toxicity in this marginal Cu diet study are 40 mg Mo/kg bw/day, consistent with the results of guideline developmental and reproductive toxicity studies of SMD. The results of Fungwe et al. were not replicated, even at higher dose levels of Mo, and their inconsistencies with guideline toxicity studies of Mo are not explained by the marginal dietary Cu level.

Reproductive Parameters and Oxidative Stress Marker Impacts Associated with Oral and Inhalation Exposure to Chlorview

Aim: Factory workers, pesticide applicators and farmers are the most susceptible group to reproductive problems due to continuous exposure to pesticides. Farmers now increasingly deploy pesticides in their agronomic practices. This research aimed to assess the impact on reproductive markers and stress markers of acute exposure to chlorview, an organophosphate pesticide, through oral and inhalation routes using animal model.
 Study Design: A total of 64 male wistar rats were used for the experiment. The animals were divided into two groups for oral (36 rats) and inhalation (28 rats) routes of exposure. Acute toxicity studies and the median lethal dose were carried out using a modified method.
 Methodology: Standard methods were used to determine oxidative stress markers of lipid peroxides, catalase activity and glutathione peroxidase activity. Immunoassay test kit was used to determine the reproductive toxicity studies.
 Results: The results from the 24 hour acute toxicity studies revealed that oral exposure to pesticide gave a median lethal dose (LD50) of 155 mg/kg b.w. while inhalation exposure gave a median lethal concentration (LC50) of 1414 mg/kg b.w. for 60 min. Oxidative stress markers [glutathione (GSH), Malondialdehyde (MDA), catalase (CAT) and glutathione peroxidase (GPx)] show that the pesticide induced appreciable oxidative imbalance in the system. In oral exposure, there was a significant (p<0.05) increase in the activity when compared to control. The reproductive marker toxicity studies revealed that oral exposure to pesticide led to a significant (p<0.05) increase in the Cholesterol (which has a correlation with estradiol) and a significantly (p<0.05) decreased in testosterone and sperm count when compared to control. This research concludes that exposure to pesticides can pose a reasonable risk to reproductive and stress markers through oral and inhalation routes of exposure which affect many biochemical processes.

Evaluation of non-clinical toxicity studies of COVID-19 vaccines

In this study we evaluated the outcomes of non-clinical toxicity studies of various SARS-CoV-2 vaccines produced with different manufacturing technologies, with focus on Repeated Dose Toxicity (RDT) and Developmental and Reproductive Toxicity (DART) studies. We found that RDT and DART studies at doses relevant for human treatment showed no adverse effects while remaining observations were expected findings including local reactogenicity, immune response and macroscopic findings at the injection site. We have also reviewed the European Medicines Agency (EMA) nonclinical assessment reports for market authorization. Regardless of utilized vaccine manufacturing technology EMA assessment of the non-clinical studies consisted most frequently of comments related to study design, species selection and missing data. Sponsors have often submitted platform studies (vaccine studies with the same technology/construct but using other antigens) as supplementary data. Animal model-based toxicity testing has shown rather small effects, which have been never serious adverse effects. The translational value to support clinical development is mainly to inflammatory effects, indicative of the primary action of the vaccines. From a 3R perspective supportive platform technology data consisting of previously executed RDT and DART studies from the same platform technology are encouraged to be implemented in the vaccine assessment process.

Extended one generation reproductive toxicity study and effect on gut flora of genetically modified rice rich in β-carotene in wistar rats

To evaluate the reproductive toxicity of gene modified rice generated by introducing phytoene synthase (Psy) and bacterial phytoene desaturase (CrtI) from maize and Erwinia uredovora, Wistar rats were allocated into 3 groups and fed with Psy and CrtI gene modified rice mixture diet (GM group), non-gene modified rice mixture diet (non-GM group), and AIN-93 diet (Blank control group) from parental generation (F0) to the offsprings (F1). GM rice, Heijinmi (HJM) and Non-GM rice, Heishuai (HS), were both formulated into diets at ratios of 73.5% and 75.5% according to the AIN93 diet for rodent animals, respectively. Relative to the non-GM group, no biologically relevant differences were observed in GM group rats concerning reproductive performance such as fertility rate, gestation rate, mean duration, hormone level, and reproductive organ pathology. The developmental parameters results were not significantly different from the non-GM group such as body weight, food consumption, developmental neurotoxicity, behavior, hematology, and serum chemistry. In terms of immunotoxicity, the IgG indicators of offspring from the GM group improved in contrast with the non-GM group. Additional gut flora analysis of F0 generation rats resulted as that the treatment elicited an increased gut microflora diversity of F0 rats. And no horizontal gene transfer of Psy and CrtI genes in rats fed a GM rice HJM diet. In conclusion, we found no adverse effects related to GM rice in the extended one-generation reproductive toxicity study, indicating that GM rice is a safe alternative for its counterpart rice regarding reproductive toxicity.