Immunotoxicity Studies Research Articles

Bioinspired orthogonal-shaped protein-biometal nanocrystals enable oral protein absorption.

With the growing number of marketed biological drugs, the development of technological strategies for their oral systemic absorption, becomes increasingly important. The harsh gastrointestinal environment and low permeability of the intestinal epithelium, represent a huge challenge for their systemic delivery. Herein, bioinspired in the physiological insulin-Zn interaction, the design of orthogonal-shaped protein-biometal hybrid nanocrystals, further enveloped by a bilayer of functional biomaterials, is reported. The nanocrystals exhibited a size of 80 nm, a neutral surface charge and a high insulin loading. In vitro studies showed the capacity of the nanocomplexes to control the release of the associated insulin, while preserving its stability. In vivo evaluation showed sustained blood glucose reductions in both healthy and diabetic rats (up to 40 % and 80 %, respectively), while chronic immunotoxicity studies in mice indicated no toxicity effect. Preliminary efficacy studies in healthy awake pigs following oral capsule administration showed over 20 % absolute bioavailability.

The study of genotoxicity and immunotoxicity in workers occupationally exposed to cyanide

The study of genotoxicity and immunotoxicity in workers occupationally exposed to cyanide

Detection of Beta-Glucan Contamination in Nanoparticle Formulations.

Beta-glucans with diverse chemical structures are produced by a variety of microorganisms and are commonly found in microbial cell walls. β-(1,3)-D-glucans are present in yeast and fungi, and, for this reason, their traces are commonly used as a sign of yeast or fungal infection or contamination. Despite being less immunologically active than endotoxins, beta-glucans are pro-inflammatory and can activate cytokines and other immunological responses via their cognate pattern recognition receptors. Unlike endotoxins, there is no established threshold pyrogen dose for beta-glucans; as such, their quantity in pharmaceutical products is not regulated. Nevertheless, regulatory agencies recognize the potential contribution of beta-glucans to the immunogenicity of protein-containing drug products and recommend assessing beta-glucans to aid the interpretation of immunotoxicity studies and assess the risk of immunogenicity. The protocol for the detection and quantification of β-(1,3)-D-glucans in nanoparticle formulations is based on a modified limulus amoebocyte lysate assay. The results of this test are used to inform immunotoxicity studies of nanotechnology-based drug products.

Role of CdTe quantum dots on peripheral Immunocytes and selenoprotein P: immunotoxicity at the molecular and cellular levels.

The extensive product and application of cadmium-quantum dots (Cd-QDs), one kind of semiconductor nanomaterials, lead to prolonged exposure to the environment. Cd-QDs have shown good properties in biomedical and imaging-related fields; the safety of Cd-QDs limits the application of these materials and technologies, however. The systematic distribution of CdTe QDs in organisms has been ascertained in previous studies. Nevertheless, it is relatively less reported about the toxicity of CdTe QDs to immune macromolecules and organs. Based on this, immunocytes (including lymphocyte subsets-CD4+ T and CD8+ T cells, splenocytes) and selenoprotein P (SelP) were chosen as targets for CdTe QDs immunotoxicity studies. Results indicate that CdTe QDs induced cytotoxicity to CD4+ T cells, CD8+ T cells and splenocytes by reducing cell viability and causing apoptosis as CdTe QDs and Cd2+ enter cells. At the molecular level, the direct interaction between CdTe QDs and SelP is proved by multispectral measurements, which demonstrated the alteration of protein structure. The combined results show that CdTe QDs induced adverse effects on the immune system at the cellular and molecular levels. This research contributes to a better understanding of CdTe QDs cause harmful damage to the immune system and provides new strategies for the inhibition and treatment of health damages caused by CdTe QDs.

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.

Evaluation of the immunotoxicity and allergenicity of a new intranasal influenza vector vaccine against tuberculosis carrying TB10.4 and HspX antigens.

A new vaccine candidate TB/FLU-05E has been developed at the Smorodintsev Research Institute of Influenza (Russia). The vaccine is based on the attenuated influenza strain A/PR8/NS124-TB10.4-2A-HspX that expresses mycobacterial antigens TB10.4 and HspX. This article describes the results of preclinical immunotoxicity and allergenicity studies of the new vector vaccine TB/FLU-05E against tuberculosis. The experiments were conducted on male CBA mice, С57/black/6 mice, and guinea pigs. The vaccine candidate was administered intranasally (7.7 lg TCID50/animal and 8.0 lg TCID50/animal) twice at a 21-day interval. The immunotoxic properties of the vaccine were assessed in mice according to the following parameters: spleen and thymus weight and their organ-to-body weight ratio, splenic and thymic cellularity, hemagglutination titer assay, delayed-type hypersensitivity test, and phagocytic activity of peritoneal macrophages. Histological examination of the thymus and spleen and white blood cell counts were also performed. Allergenicity of the vaccine was assessed in guinea pigs using conjunctival and general anaphylaxis reaction tests. The results showed that double immunization with the TB/FLU-05E vaccine did not affect the phagocytic activity of peritoneal macrophages, cellular and humoral immunity after immunization with a heterologous antigen (sheep red blood cells), or the organ-to-body weight ratio of immunocompetent organs (thymus and spleen). The vaccine candidate demonstrated no allergenic properties. According to the results of this study, the TB/FLU-05E vaccine is well-tolerated by the immune system and demonstrates no immunotoxicity or allergenicity.

Biocompatibility and biodistribution of matrix-bound nanovesicles in vitro and in vivo.

Matrix-bound nanovesicles (MBV) are a distinct subtype of extracellular vesicles that are firmly embedded within biomaterials composed of extracellular matrix (ECM). MBV both store and transport a diverse, tissue specific portfolio of signaling molecules including proteins, miRNAs, and bioactive lipids. MBV function as a key mediator in ECM-mediated control of the local tissue microenvironment. One of the most important mechanisms by which MBV in ECM bioscaffolds support constructive tissue remodeling following injury is immunomodulation and, specifically, the promotion of an anti-inflammatory, pro-remodeling immune cell activation state. Recent in vivo studies have shown that isolated MBV have therapeutic efficacy in rodent models of both retinal damage and rheumatoid arthritis through the targeted immunomodulation of pro-inflammatory macrophages towards an anti-inflammatory activation state. While these results show the therapeutic potential of MBV administered independent of the rest of the ECM, the in vitro and in vivo safety and biodistribution profile of MBV remain uncharacterized. The purpose of the present study was to thoroughly characterize the pre-clinical safety profile of MBV through a combination of in vitro cytotoxicity and MBV uptake studies and in vivo toxicity, immunotoxicity, and imaging studies. The results showed that MBV isolated from porcine urinary bladder are well-tolerated and are not cytotoxic in cell culture, are non-toxic to the whole organism, and are not immunosuppressive compared to the potent immunosuppressive drug cyclophosphamide. Furthermore, this safety profile was sustained across a wide range of MBV doses. STATEMENT OF SIGNIFICANCE: Matrix-bound nanovesicles (MBV) are a distinct subtype of bioactive extracellular vesicles that are embedded within biomaterials composed of extracellular matrix (ECM). Recent studies have shown therapeutic efficacy of MBV in models of both retinal damage and rheumatoid arthritis through the targeted immunomodulation of pro-inflammatory macrophages towards an anti-inflammatory activation state. While these results show the therapeutic potential of MBV, the in vitro and in vivo biocompatibility and biodistribution profile of MBV remain uncharacterized. The results of the present study showed that MBV are a well-tolerated ECM-derived therapy that are not cytotoxic in cell culture, are non-toxic to the whole organism, and are not immunosuppressive. Collectively, these data highlight the translational feasibility of MBV therapeutics across a wide variety of clinical applications.

Assessing the ecotoxicity of combined exposure to triphenyltin and norfloxacin at environmental levels: A case study of immunotoxicity and metabolic regulation in carp (Cyprinus carpio)

This paper evaluates the coexistence risks of triphenyltin (TPT) and norfloxacin (NOR) to aquatic organisms in the aquatic environment. Carp (Cyprinus carpio) was used as the test organism, the control and exposure groups (1 μg/L TPT), 1 mg/L (NOR), 1 μg/LTPT+1 mg/LNOR (TPT_NOR)) were set up according to the environmental concentration in the severely polluted area for 42 days. The single/combined toxic effects of TPT and NOR on aquatic organisms were evaluated by analyzing carp brain transcriptome sequencing, gut microbiota structure, and detection of biochemical indicators and RT-qPCR. Our results show that TPT and NOR induce lipid metabolism disorder in carp brain tissue, affecting the metabolism of cytochrome P450 to exogenous substances, and NOR also induces immunosuppression in carp. Long-term exposure to TPT combined with NOR amplifies the monotoxicity of TPT or NOR on lipid metabolism and immunosuppression in carp, induces immune dysfunction in brain tissue and changes in gut microbiota structure. However, TPT_NOR has no obvious neurotoxicity on the brain, but it can inhibit the level of intestinal MDA. This highlights that co-exposure of TPT and NOR amplifies metabolic disorders and immunosuppressive functions in carp.

Lymphocyte subsets and immunoglobulin levels in peripheral blood from cynomolgus monkeys (Macaca fascicularis) of different age groups.

Immunotoxicity assessment is an important part of non-clinical safety evaluation of biotechnology-derived pharmaceuticals. The reference ranges of evaluated parameters, which depend on the sex, age and geographical origin of animals, play a significant role in interpreting the study results. The aim of this study was to determine the reference ranges of parameters commonly used for non-clinical immunotoxicity studies in cynomolgus monkeys (Macaca fascicularis) of different ages. The percentages of CD3+, CD4+, CD8+, CD20+, CD16/56+ lymphocytes, and the serum levels of immunoglobulins A, M, G and E in clinically healthy cynomolgus monkeys of both sexes and different ages (37-104 months) were analysed. The lymphocyte subsets were assessed by flow cytometry and serum immunoglobulin levels were determined by enzyme-linked immunosorbent assay. Statistical analysis showed a weak rank correlation of CD3+, CD20+ lymphocyte levels with the ages of female and male cynomolgus monkeys, and no significant correlation with age for the combined data of both sexes. The serum levels of immunoglobulins A, M, G and E did not have a significant rank correlation with age for the combined data of both sexes, whereas IgA levels in females and IgG levels in males were weakly correlated with age. Overall, these results justify the use of animals aged three to eight years for non-clinical immunotoxicity evaluation of biotechnology-derived pharmaceuticals. It is important to avoid the formation of animal groups with extreme ages (three years or eight years) in one group during randomization.

Levels of anti-cyclic citrullinated peptide and antinuclear antibodies in Brazilian agricultural workers exposed to pesticides and fertilizers

Despite evidence from human and animal studies of pesticide immunotoxicity, little is known about the relationship between agricultural pesticide use and autoimmunity. The objective of the present study was to assess the association between pesticide use and anti-cyclic citrullinated peptide (anti-CCP) antibodies and antinuclear antibodies (ANA) levels. A cross-sectional study including healthy 52 agricultural and 68 non-agricultural workers aged 17–69 years was conducted in the Rio de Janeiro State, Brazil. Serum samples were tested for anti-CCP and ANA by ELISA. Data on pesticide use and covariates were obtained through structured questionnaires. We estimated associations of pesticides and other exposures with log-transformed antibody levels, adjusted for sex, age, education, crops, and fertilizers by multiple linear regression analyzes. Anti-CCP levels were associated with growing certain crops, agricultural tasks, and the use of mancozeb, paraquat, and methomyl. ANA levels were positively associated with azoxystrobin and inversely associated with linuron. These novel findings suggest associations of specific pesticides and fertilizers with anti-CCP antibodies in this healthy agricultural population, supporting the need for larger human studies of preclinical autoimmunity and pesticides.

INVESTIGATION OF THE IMMUNOTOXIC PROPERTIES OF STRAWBERRY GARDEN LEAF EXTRACT DRY

Abstract: The main task of the preclinical study of the effect of potential drugs on the immune system is to prove or exclude the possibility of developing an immunotoxic effect caused by a pharmacological agent or its metabolites in an animal experiment. The proposed approach to assessing the immunotoxic effect of pharmacological agents consists in the study of a number of integral immunological functions that allow, taking into account the results of hematological and morphological studies of lymphoid organs, to assess the possible risk when using a new pharmacological agent. Mandatory testing for immunotoxicity should be subject to new, original pharmacological agents, as well as well-known drugs for which there is no data on the study of immunotoxicity, recommended for use in long repeated courses; use in pediatric practice, as well as for the treatment of pregnant women and when prescribed during lactation; as prophylactic agents and contraceptives; for use without a doctor's appointment among the general population [2,3]. Strawberry garden leaf extract dry (strawberry garden extract) is one of the potential substances for obtaining safe medicines for the prevention and treatment of diseases of the urinary tract, as it has diuretic and anti-inflammatory activity [4]. The study of the immunotoxic properties of strawberry garden extract is an obligatory part of the preclinical safety assessment of a new pharmacological substance for obtaining safe medicines with it. In this regard, studies on the study of the immunotoxic properties of strawberry leaves of dry extract in the framework of preclinical studies and substantiation of the use of the substance for the further development of medicines based on it are relevant.

Immunotoxicity studies of sulfolane following developmental exposure in Hsd:Sprague Dawley SD rats and adult exposure in B6C3F1/N mice

Sulfolane is a solvent used in the petrochemical industry and a groundwater contaminant in areas near refineries. The current studies were conducted to assess the impact of oral exposure to sulfolane on the immune system using two models: (1) a perinatal drinking water exposure to 0, 30, 100, 300, or 1000 mg/L from gestation day (GD) 6 until ∼13 weeks-of-age in Harlan Sprague Dawley rats; and, (2) a 90-day gavage exposure of adult female B6C3F1/N mice to 0, 1, 10, 30, 100, or 300 mg/kg/day. Immune parameters evaluated included measurement of antibody production against sheep red blood cells (SRBC) and keyhole limpet hemocyanin (KLH), ex vivo measurements of natural killer (NK) cell activity, cytotoxic T-cell (CTL) activity, and T-cell proliferation, as well as measures of splenic immune cell populations, hematological parameters, and histopathology of immune tissues. A decrease in ex vivo NK cell activity was observed in cells from female – but not male – F1 rats following developmental exposure. In adult female mice, splenic NK cell number was lower than the vehicle controls at doses ≥ 100 mg/kg; however, ex vivo NK cell activity was not affected by sulfolane treatment. In female mice, a decrease in the number of large unstained cells at doses ≥ 30 mg/kg was observed. In F1 rats, effects on white blood cells (WBC) were limited to a decreasing trend in leukocytes in females; no effects were observed in males. Under the conditions of this study, a no-observed-effect level (NOEL) of 3 mg/kg/day was identified based on reduced NK cell activity in female F1 rats. Overall, these findings suggest that oral exposure to sulfolane in rodents had minimal effects on the immune system.

Evaluation of allergenic properties and immunotoxicity tablet dosage form GML-1 (N-benzyl-N-methyl-1-phenylpyrrolo[1,2-a]pyrazin-3-carboxamide)

The study of allergenic properties and immunotoxic effects of the ready-to-use drug form of GML-1 (N-benzyl-N-methyl-1-phenylpyrrolo[1,2-a] pyrazin-3-carboxamide), compounds with high TSPO affinity and pronounced anxiolytic activity, was carried out. The study of allergenic properties and immunotoxicity of GML-1 was performed on male albino guinea pigs weighing 250-300 g and on male CBA, C57BL / 6, F1 hybrids (CBAxC57BL/6) mice. When assessing immunotoxicity, GML-1 was inject to mice per os for 14 days in doses of 2.2 mg / kg and 22 mg / kg. When studying the allergenicity, GML-1 was injected to albino guinea pigs in doses of 1 mg / kg and 10 mg / kg according to standard regimens of immunization. The results of the study of the immuno-toxicity and allergenicity of GML-1 allow us to conclude that the injection of tablet dosage form of GML-1 in the range of studied doses does not have an immunotoxic effect and allergenic properties.

Evaluation of allergenic properties and immunotoxicity of dipeptide mimetic of brain-derived neurotrophic factor GSB-106

The study of allergenic properties and immunotoxic effects of the ready-to-use drug form of GSB-106 was carried out. The study of allergenic properties and immunotoxicity of GSB-106 was performed on male albino guinea pigs weighing 250-300 g and on male CBA, C57BL / 6, F1 hybrids (CBAxC57BL / 6) mice. When assessing immunotoxicity, GSB-106 was inject to mice per os for 14 days in doses of 2.2 mg / kg and 22 mg / kg. When studying the allergenicity, GSB-106 was injected to albino guinea pigs in doses of 1 mg / kg and 10 mg / kg according to standard regimens of immunization. The results of the study of the immunotoxicity and allergenicity of GSB-106 allow us to conclude that the injection of the ready-to-use drug form of GSB-106 in the range of studied doses does not have an immunotoxic effect and does not have allergenic properties.

Nonclinical regulatory immunotoxicity testing of nanomedicinal products: Proposed strategy and possible pitfalls.

Various nanomedicinal products (NMPs) have been reported to induce an adverse immune response, which may be related to their tendency to accumulate in or target cells of the immune system. Therefore, before their market authorization, NMPs should be thoroughly evaluated for their immunotoxic potential. Nonclinical regulatory immunotoxicity testing of nonbiological medicinal products, including NMPs, is currently performed by following the guideline S8 “Immunotoxicity Studies for Human Pharmaceuticals” of the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH). However, this guideline does not cover all the immunotoxicity endpoints reported for NMPs in the literature, such as complement activation related pseudo allergy, hypersensitivity and immunosuppression. In addition, ICH‐S8 does not provide any nanospecific testing considerations, which is important given their tendency to interfere with many commonly used toxicity assays. We therefore propose a nonclinical regulatory immunotoxicity assessment strategy, which considers the immunotoxicity endpoints currently missing in the ICH‐S8. We also list the known pitfalls related to the testing of NMPs and how to tackle them. Next to defining the relevant physicochemical and pharmacokinetic properties of the NMP and its intended use, the proposed strategy includes an in vitro assay battery addressing various relevant immunotoxicity endpoints. A weight of evidence evaluation of this information can be used to shape the type and design of further in vivo investigations. The final outcome of the immunotoxicity assessment can be included in the overall risk assessment of the NMP and provide alerts for relevant endpoints to address during clinical investigation.This article is categorized under:Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in NanomedicineToxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials

Immunotoxicity studies of trans-resveratrol in male B6C3F1/N mice

Resveratrol is a naturally occurring polyphenol that is being investigated to treat and prevent various diseases, both experimentally and in the clinic. Despite increased use and interest in resveratrol due to its immunomodulatory properties, there is a lack of studies evaluating potential toxicities, particularly immunotoxicity, associated with resveratrol use. A previous 2-week study found decreasing thymus weight in male B6C3F1/N mice with increasing exposure to trans-resveratrol. This study is a follow-up on those findings by evaluating immune function. Male adult B6C3F1/N mice were given trans-resveratrol (0, 156, 312, 625, 1250, 2500 mg/kg/day) via oral gavage for 28 days and functional immune tests and histopathology were evaluated. There were no treatment-related effects on body weight during the study. Humoral, cell-mediated, and innate immune function were not altered after 28 days of trans-resveratrol treatment. There were also no changes in organ weight or microscopic alterations in immune organs. Overall, under the conditions of this study, there was no evidence of immunotoxicity or improvements in immune function associated with oral exposure to trans-resveratrol in male mice. Importantly, the immunomodulatory benefits of resveratrol may require a prerequisite level of inflammatory activity and may not be observable in healthy individuals.

Effect of the immobilized microcystin-LR-degrading enzyme MlrA on nodularin degradation and its immunotoxicity study

In freshwater ecosystems with frequent cyanobacterial blooms, the cyanobacteria toxin pollution is becoming increasingly serious. Nodularin (NOD), which has strong biological toxicity, has emerged as a new pollutant and affects the normal growth, development and reproduction of aquatic organisms. However, little information is available regarding this toxin. In this study, a graphene oxide material modified by L-cysteine was synthesized and used to immobilize microcystin-LR (MC-LR)-degrading enzyme (MlrA) to form an immobilized enzyme nanocomposite, CysGO-MlrA. Free-MlrA was used as a control. The efficiency of NOD removal by CysGO-MlrA was investigated. Additionally, the effects of CysGO-MlrA and the NOD degradation product on zebrafish lymphocytes were detected to determine the biological toxicity of these two substances. The results showed the following: (1) There was no significant difference in the degradation efficiency of NOD between CysGO-MlrA and free-MlrA; the degradation rate of both was greater than 80% at 1 h (2) The degradation efficiency of the enzyme could retain greater than 81% of the initial degradation efficiency after the CysGO-MlrA had been reused 7 times. (3) CysGO-MlrA retained greater than 50% of its activity on the 8th day when preserved at 0 °C, while free-MlrA lost 50% of its activity on the 4th day. (4) CysGO-MlrA and the degradation product of NOD showed no obvious cytotoxicity to zebrafish lymphocytes. Therefore, CysGO-MlrA might be used as an efficient and ecologically safe degradation material for NOD.

The assessment of xenogeneic bone immunotoxicity and risk management study

BackgroundXenogeneic bone has been widely used in a variety of clinical bone-related disease to promote bone healing and restore bone defects. However, the adverse effects of immune system limit its application in the clinic. The aim of this study was to evaluate xenogeneic bone safety of immunotoxicity and explore the methods for immune risk supervision.ResultsXenogeneic bone, which is freeze-dried bovine cancellous bone, was implanted into the muscle of mice. On day 7, 14 and 28, the effects of xenogeneic bone were examined on humoral immunity and cellular immunity, including the levels of IgG, IgM, C3, inflammatory factors (TNF-α, IL-6), alkaline phosphatase (ALP) and the lymphocyte phenotype. The data showed that xenogeneic bone implantation had no potential to induce immune responses not only in humoral immunity but also in cellular immunity. To reveal the risk of immunogenicity, the residual DNA and the clearance of α-gal epitope were analyzed in 2 different bones (bone 1 is deproteinized bone, bone 2 is acellular and defatted bone). It was suggested that DNA of xenogeneic bone can be limited to < 50 ng per mg dry weight for the repair or regeneration with the acceptable immune risk. And α-gal clearance of xenogeneic bone could be an effective risk factor for improving xenograft quality management.ConclusionsThrough the detection of xenogeneic bone immunotoxicity, our findings indicated that the supervisions of risk factors could contribute to reduce the immune risk. And the risk factors under the acceptable limitation could decrease or replace animal experiment. However, it still needs to be studied on the limitation of α-gal epitope to predict rejection of xenogeneic bone more accurately.

Variance of body and organ weights in 28-day studies in mice

The OECD guideline 407 outlines the conduct of 28-day studies in rodents to detect systemic toxicity with focus on endocrine and immunotoxic effects. It was validated with the rat as preferred model species. Justification is required for other rodent species, as an increased variability is expected compared to the rat. We investigated the variability of organ weights in the mouse and compared this to data published for the rat in the validation report of test guideline 407. Furthermore, the influence of the immunotoxic model substance cyclophosphamide on spleen and thymus weights in the mouse in immunotoxicity studies (duration 28 days) is reported and discussed, an immunotoxic model substance was not included in the validation report. Historical control data were compiled for mouse studies performed according to OECD 407 and for immunotoxicity studies between 2008 and 2013 at BASF SE. For absolute weights, the coefficient of variation was determined for each study group and compared with the rat. Adrenal glands, ovaries and to lesser degree testes and prostate showed higher coefficients of variation in the mouse (most pronounced in adrenal glands in male animals: rat 5%–17%, CD1 mouse 20%–51%). Effects of cyclophosphamide were best detected measuring the thymus weight.

Minimal uranium accumulation in lymphoid tissues following an oral 60-day uranyl acetate exposure in male and female C57BL/6J mice.

High levels of uranium (U) exist in soil, water, and air in the Southwestern United States due, in part, to waste generated from more than 160,000 abandoned hard rock mines located in this region. As a result, many people living in this region are chronically exposed to U at levels that have been linked to detrimental health outcomes. In an effort to establish a relevant in vivo mouse model for future U immunotoxicity studies, we evaluated the tissue distribution of U in immune organs; blood, bone marrow, spleen, and thymus, as well as femur bones, kidneys, and liver, following a 60-d drinking water exposure to uranyl acetate (UA) in male and female C57BL/6J mice. Following the 60-d exposure, there was low overall tissue retention of U (<0.01%) at both the 5 and the 50 ppm (mg/L) oral concentrations. In both male and female mice, there was limited U accumulation in immune organs. U only accumulated at low concentrations in the blood and bone marrow of male mice (0.6 and 16.8 ng/g, respectively). Consistent with previous reports, the predominant sites of U accumulation were the femur bones (350.1 and 399.0 ng/g, respectively) and kidneys (134.0 and 361.3 ng/g, respectively) of male and female mice. Findings from this study provide critical insights into the distribution and retention of U in lymphoid tissues following chronic drinking water exposure to U. This information will serve as a foundation for immunotoxicological assessments of U, alone and in combination with other metals.