Differential Toxicological Outcome of Corn Oil Exposure in Rats and Mice as Assessed by Microbial Composition, Epithelial Permeability, and Ileal Mucosa-Associated Immune Status

Corn oil and Soybean oil effect as vehicles on behavioral and oxidative stress profiles in developmentally exposed offspring mice

Corn and soybean oils are among the most frequently used vehicles for water-insoluble compounds in toxicological studies. These two vegetable oils are nutrients and may induce some biological effects on animals that might interfere with the experimental results. However, their chronic effects on a developing brain have not been reported. This study aims to evaluate the neurobehavioral and brain biochemical effects of both oils on male and female Swiss albino mice. Pregnant female mice were exposed to 1 µl/g/d of either tap water, corn oil (CO), or soybean oil (SO) from early gestation (GD1) until weaning then offspring mice were exposed to the same treatment regimen until adulthood (PND70). Our results showed that developmental exposure to both oils induced body weight changes in offspring mice. In addition, we detected some behavioral abnormalities where both oil-treated groups showed a significant decrease in locomotor activity and greater levels of anxiety behavior. Moreover, our results suggest that continuous exposure to these oils may alter motor coordination, spatial memory and induce depression-like behavior in adult mice. These alterations were accompanied by increased malondialdehyde, superoxide dismutase, and glutathione peroxidase activities in specific brain regions. Together, these data suggest that exposure to CO and SO as vehicles in developmental studies may interfere with the behavioral response and brain redox homeostasis in offspring mice.

Early Developmental Exposure to Triclosan Impacts Fecal Microbial Populations, IgA and Functional Activities of the Rat Microbiome

Triclosan (TCS), a broad-spectrum antibacterial chemical, is detected in human urine, breast milk, amniotic fluid, and feces; however, little is known about its impact on the intestinal microbiome and host mucosal immunity during pregnancy and early development. Pregnant female rats were orally gavaged with TCS from gestation day (GD) 6 to postpartum (PP) day 28. Offspring were administered TCS from postnatal day (PND) 12 to 28. Studies were conducted to assess changes in the intestinal microbial population (16S-rRNA sequencing) and functional analysis of microbial genes in animals exposed to TCS during pregnancy (GD18), and at PP7, PP28 and PND28. Microbial abundance was compared with the amounts of TCS excreted in feces and IgA levels in feces. The results reveal that TCS decreases the abundance of Bacteroidetes and Firmicutes with a significant increase in Proteobacteria. At PND28, total Operational Taxonomic Units (OTUs) were higher in females and showed correlation with the levels of TCS and unbound IgA in feces. The significant increase in Proteobacteria in all TCS-treated rats along with the increased abundance in OTUs that belong to pathogenic bacterial communities could serve as a signature of TCS-induced dysbiosis. In conclusion, TCS can perturb the microbiome, the functional activities of the microbiome, and activate mucosal immunity during pregnancy and early development.

Immunodysregulatory potentials of polyethylene or polytetrafluorethylene microplastics to mice subacutely exposed via intragastric intubation

Microplastics (MPs) have been recently recognized as posing a risk to human health. The adverse health effects of MP exposure have been recently reported, especially via the oral exposure route. The present study investigated whether subacute (4 week) exposure to polyethylene (PE) or polytetrafluorethylene (PTFE) MPs via gastric intubation caused immunotoxicity. Two different sizes of PE MPs (6.2 or 27.2 μm) and PTFE MPs (6.0 or 30.5 μm) were administered to 6-week-old mice of both sexes at 0 (corn oil vehicle control), 500, 1000, or 2000 mg/kg/day (n = 4/group). No significant differences were observed between groups in the major thymic or splenic immune cell populations, including thymic CD4+, CD8+, CD4+/CD8+ T lymphocytes, and splenic helper T cells, cytotoxic T cells, and B cells. The ratio of interferon-gamma (IFNγ) to interleukin-4 (IL-4) in culture supernatants from polyclonally activated splenic mononuclear cells ex vivo (48 h) was dose-dependently decreased in female mice that received small- and large-size PTFE MPs. The IFNγ/IL-4 ratio was also decreased in the female mice dosed with large-size PE MPs. The serum IgG2a/IgG1 ratio was dose-dependently increased in male and female animals dosed with small-size PE MPs, in female animals dosed with large-size PTFE MPs, and in male animals dosed with small-size PTFE MPs. The present study implies that immune functions could be affected in animals exposed to MPs via gastric intubation. These effects are dependent on MP size, MP dose, MP polymer type, and mouse sex. Further investigations with longer exposure periods could be necessary to more clearly define the immunotoxic effects of MPs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-023-00172-6.

Prenatal exposure to corn oil, CMC-Na or DMSO affects physical development and multi-organ functions in fetal mice

Corn oil, sodium carboxymethyl cellulose (CMC-Na), and dimethyl sulfoxide (DMSO) are widely used as solvents or suspensions in animal experiments, but the effects of prenatal exposure to them on fetal development have not been reported. In this study, Kunming mice were given a conventional dose of corn oil (9.2g/kg·d), CMC-Na (0.05g/kg·d) or DMSO (0.088g/kg·d) during gestation days 10-18, and the pregnancy outcome, fetal physical development, serum phenotype, and multi-organ function changes were observed. The results showed that corn oil decreased serum triglyceride level in males but increased their serum testosterone and CORT levels, and affected female placenta and female/male multi-organ functions (mainly bone, liver, kidney). CMC-Na increased female/male body lengths and tail lengths, decreased serum glucose and total cholesterol levels in males as well as increased their serum LDL-C/HDL-C ratio and testosterone level, decreased female serum bile acid level, and affected male/female placenta and multi-organ functions (mainly bone, liver, hippocampus). DMSO decreased male body weight and serum glucose level, decreased male/female serum bile acid levels, and affected male/female placenta and multi-organs functions (mainly bone, hippocampus, adrenal gland). In conclusion, prenatal exposure to a conventional dose of corn oil, CMC-Na or DMSO could affect fetal physical development and multi-organ functions, and has the characteristics of "multi-pathway, multi-organ and multi-target". This study provides the experimental basis for the rational selection of solvents or suspensions in pharmacology and toxicology studies. DATA AVAILABILITY: Data will be made available on request.

Diallyl trisulfide modulated autophagy in isoproterenol induced acute myocardial infarction

Background

Acute myocardial infarction (AMI) is the most serious manifestation of coronary artery disease. The initial ischemia in AMI causes biochemical and metabolic alterations in cardiomyocytes.

Objectives

The present study aimed to investigate the biomolecular mechanisms underlying cardioprotective effects of diallyl trisulfide (DATS) as well as captopril (CAP) in isoproterenol (ISO) induced AMI focusing on autophagy & PI3K/Akt signaling.

Methods

Seventy male Albino rats were divided into seven groups as follows: Normal control, ISO, ISO + LY294002 (PI3K inhibitor), DATS+ISO, CAP+ISO, DATS+LY294002 + ISO, and CAP+LY294002 + ISO. All treatments (40 mg/kg DATS, 50 mg/kg CAP & 0.3 mg/kg LY294002) were given daily for two weeks before ISO injection (85 mg/kg for 2 days). At the end of the experiment, serum and cardiac tissues were collected. Serum cardiac troponin I (cTnI), and creatine kinase MB (CK-MB) were measured. Cardiac glutathione peroxidase (GSH-px), malondialdehyde (MDA), hypoxia-inducible factor 1 alpha (HIF-1α), autophagy proteins (P62 & LC3IIB) and gene expression of PI3K, Akt, FOXO-1, and eNOS were assessed. Histopathological examination of heart tissue was performed.

Results

DATS and CAP significantly (p < 0.01) decreased serum CK-MB and cTnI, cardiac levels of MDA, HIF-1α, p62 and LC3IIB along with an increase in GSH-px activity compared with ISO group. Moreover, DATS and CAP significantly up-regulated PI3K, Akt, and eNOS gene expression but down-regulated FOXO-1 expression compared to ISO group. However, LY294002 reversed DATS and CAP cardioprotective effects.

Conclusion

DATS and CAP prior treatment proved cardioprotective effects via modulation of autophagy, PI3K/Akt signaling, eNOS and FOXO-1 downregulation in ISO induced AMI rat model.

Cytochrome P450 isoforms contribution, plasma protein binding, toxicokinetics of enniatin A in rats and in vivo clearance prediction in humans

Emerging mycotoxins, such as enniatin A (ENNA), are becoming a worldwide concern owing to their presence in different types of food and feed. However, comprehensive toxicokinetic data that links intake, exposure and toxicological effects of ENNA has not been elucidated yet. Therefore, the present study investigated the in vitro (rat and human) and in vivo (rat) toxicokinetic properties of ENNA. Towards this, an easily applicable and sensitive bioanalytical method was developed and validated for the estimation of ENNA in rat plasma. ENNA exhibited high plasma protein binding (99%), high hepatic clearance and mainly underwent metabolism via CYP3A4 (74%). The in-house predicted hepatic clearance (54 mL/min/kg) and observed in vivo rat clearance (55 mL/min/kg) were comparable. The predicted in vivo human hepatic clearance was 18 mL/min/kg. ENNA underwent slow absorption (T_max = 4 h) and rapid elimination following oral administration to rats. The absolute oral bioavailability was 47%. The toxicokinetic findings for ENNA from this study will help in designing and interpreting toxicological studies in rats. Besides, these findings could be used in physiologically based toxicokinetic (PBTK) model development for exposure predictions and risk assessment for ENNA in humans.

In Vivo Evaluation of the Oral Toxicity of the Chlorobutanol

Chlorobutanol (CB) is used as a preservative in cosmetics and has antibacterial activity. This study investigated the single- and repeated-dose 28-day oral toxicity of a CB solvent in Sprague Dawley (SD) rats. For the single-dose oral toxicity study, a dose of 62.5, 125, or 250 mg per kg of body weight (mg/kg b.w.) of CB was given once orally via gavage. For the repeated-dose 28-day toxicity study, the high dose was set as 100 mg/kg b.w./day, and the middle, middle-low, and low doses were set to 50, 25, and 12.5 mg/kg b.w./day, respectively. Body weight was not significantly changed in the repeated-dose toxicity study. Relative liver and kidney weights were significantly increased in both sexes of the 100 mg/kg b.w./day treatment group. However, there were histopathological changes in liver and kidney for females and males, respectively. These data suggested that the approximate lethal dose (ALD) of CB was over 250 mg/kg b.w./day in the single-dose study, and the no adverse effect level (NOAEL) for CB was over 50 and 12.5 mg/kg b.w./day for female and male rats in the repeated-dose toxicity study.