Dibutyl phthalate adsorbed on multi-walled carbon nanotubes can aggravate liver injury in mice via the Jak2/STAT3 pathway.

Phthalic acid esters (PAEs) and carbon nanotubes (CNTs) are common environmental pollutants and may degrade differently with different resulting biotoxicity, when present together. This study investigated the toxicological effects of singular or combined exposure to dibutyl phthalate (DBP) and multi-walled carbon nanotubes (MWCNTs) in KM mice. Results indicated that combined exposure led to slower weight gain and an increased leukocyte count in the blood, as well as liver tissue lesions and downregulation of organ coefficients. Additionally, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were elevated in the liver, and glucose, pyruvate, triglyceride (TG), and total cholesterol (T-CHO) were significantly reduced, suggesting compromised liver function. Furthermore, mRNA levels of genes related to hepatic glucose and lipid metabolism were significantly altered. These findings suggest that combined exposure to DBP and MWCNTs can have severe impacts on liver function in mice, highlighting the importance of considering interactions between multiple contaminants in environmental risk assessments.

Influence of formaldehyde exposure on the molecules of the NO/cGMP-cAMP signaling pathway in different brain regions of Balb/c mice.

This toxicology study was conducted to assess the impact of formaldehyde, a common air pollutant found in Chinese gymnasiums, on the brain function of athletes. In this research, a total of 24 Balb/c male mice of SPF-grade were divided into four groups, each consisting of six mice. The mice were exposed to formaldehyde at different concentrations, including 0 mg/m3, 0.5 mg/m3, 3.0 mg/m3, and 3.0 mg/m3 in combination with an injection of L-NMMA (NG-monomethyl-L-arginine), which is a nitric oxide synthase antagonist. Following a one-week test period (8 h per day, over 7 days), measurements of biomarkers related to the nitric oxide (NO)/cGMP-cAMP signaling pathway were carried out on the experimental animals post-treatment. The study found that: (1) Exposure to formaldehyde can lead to brain cell apoptosis and neurotoxicity; (2) Additionally, formaldehyde exposure was found to alter the biomarkers of the NO/cGMP-cAMP signaling pathway, with some changes being statistically significant (p < 0.05 or p < 0.01); (3) The use of L-NMMA, an antagonist of the NO/cGMP-cAMP signaling pathway, was found to prevent these biomarker changes and had a protective effect on brain cells. The study suggests that the negative impact of formaldehyde on the brain function of mice is linked to the regulation of the NO/cGMP-cAMP signaling pathway.

Combined exposure to multiwalled carbon nanotubes and dibutyl phthalates aggravated airway inflammation in rats.

Previous work has shown that mice exposed to dibutyl phthalate (DBP) adsorbed onto multi-walled carbon nanotubes (MWCNTs), via tail vein injection, displayed black lesions in their lungs. To investigate the mechanism causing this toxicity in the lung tissue, we performed an experiment with rats, exposing them to DBP adsorbed onto MWCNTs via a tail vein injection for 14 days. The results revealed pulmonary edema and greyish-black lung tissue in the MWCNTs and the MWCNTs + DBP combined exposure groups. In the combined exposure group there was evident alveolar fragmentation and adhesion, and lung tissue sections showed significant levels of black particles. Sections of the non-cartilaginous region of the trachea had significant folding of the pseudostratified ciliated columnar epithelium and marked thickening of the submucosa. In broncho alveolar lavage fluid, the number of leukocytes (WBC), lymphocytes (Lym), neutrophils (Neu), and eosinophils (Eos), as well as levels of immunoglobulin E (IgE), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), and interleukin 1ß (IL-1ß) were all significantly higher. TNF-α, IL-6, signal transducer and activator of transcription 3 (STAT3), and α-smooth muscle actin (α-SMA) mRNA expression were all elevated in the lung tissue. The combined exposure group, which had considerable airway remodeling, had a greater degree of tracheal constriction and luminal narrowing, according to the results of the α-SMA immunofluorescence assay. According to these experimental findings, the exposure to both MWCNTs and DBP seemed to have a synergistic effect and exacerbated rats' impaired respiratory function that resulted from exposure to MWCNTs alone.

Dibutyl Phthalate Adsorbed on Multiwalled Carbon Nanotubes Causes Fetal Developmental Toxicity in Balb/C Mice.

This study investigated whether using multiwalled carbon nanotubes (MWCNTs) as a carrier for dibutyl phthalate (DBP) could delay the degradation rate of DBP in mice and increase its estrogen-like interference effect. Pregnant Balb/C mice were divided into four groups and exposed to different treatments via tail-vein injection every 3 days until gestational day 20. The female and male mice were then sacrificed for toxicological study. The results showed that the combination of MWCNTs and DBP resulted in a higher fetal mortality rate than if the mice were exposed to MWCNTs or DBP alone. H&E staining showed that the estrous period of the exposed mice was delayed, the development of oocytes was blocked in the combination group, the number of spermatogenic cells decreased, and the quality of sperm decreased. Our experiment showed that the expression levels of the genes involved in sex hormone synthesis in the testis and ovaries were significantly increased after combined treatment compared with the MWCNT group (p < 0.01). The study suggests that DBP degradation is delayed when absorbed on MWCNTs, which increases its estrogen-like interference and interferes with fetal development, ultimately leading to increased fetal mortality.

Exposure to dibutyl phthalate adsorbed to multi-walled carbon nanotubes causes neurotoxicity in mice by inducing the release of BDNF.

Multi-walled carbon nanotubes (MWCNTs) and dibutyl phthalate (DBP) exist extensively in the environment, and they are easy to form compound pollution through π-π interactions in the environment. We investigate whether DBP, an environmental hormone disruptor, mediated by CNTs can more easily cross the blood-brain barrier, and whether DBP entering the brain has neurotoxic effects on the cells in the brain. Experimental subjects were 40 male Kunming (KM) mice randomly divided into 4 groups: the control group; the MWCNTs group; the DBP group; and the MWCNTs+DBP group. The mice were exposed via tail intravenous injection once every 3 days for 21 days, following which toxicology studies were carried out. The results of behavioral experiments showed that the mice in the combined exposure group (MWCNTs+DBP) exhibited spatial learning and memory impairment, and anxiety-like behavior. Staining of hippocampal sections of mouse brain tissue showed that, in the CA1, CA2, and DG areas, the number of neurons decreased, the nucleus was pyknotic, the cell body was atrophied, and levels of the microglia marker Iba-1 increased. By proteomic KEGG analysis, we found that the DEPs were mainly those related to neurodegenerative diseases. Immunohistochemistry in the hippocampus indicated that the level of brain-derived neurotrophic factor (BDNF) in the DG region was significantly increased. RT-PCR results revealed that the expression levels of P53, caspase3, and Bax genes related to apoptosis were up-regulated. The experimental results demonstrated that the mechanism of the combined-exposure injury to neurons in the hippocampus of mice may be that MWCNTs with adsorbed DBP can induce the release of BDNF, accelerate the apoptosis of neurons, and reduce the number of nerve cells, which activates microglia, causing neuroinflammation and nervous system toxicity.

Reproductive toxicity of dibutyl phthalate adsorbed on carbon nanotubes in male Balb/C mice.

Dibutyl phthalate (DBP) is an environmental hormone disrupter. This study was designed to investigate whether DBP adsorbed in multi-walled carbon nanotubes (MWCNTs) can easily cross the blood-testis barrier and slow down the degradation of DBP in male mice, thereby prolonging the interference effect of DBP. The results showed that: in male Balb/C mice, the sperm density of the MWCNTs group and the DBP plus MWCNTs group decreased significantly (p < 0.05); and the sperm deformity rate increased significantly (p < 0.05). Testicular tissue sections from the combined exposure group showed that most of the seminiferous tubules were atrophied, there were more large gaps between the cells in the tubules, and the number of mature-sperm decreased. The reactive oxygen species (ROS) levels increased significantly in the combined exposure group (p < 0.01). Proteomics results showed that there were 231 differentially expressed proteins in the combined exposure group compared with the MWCNTs only group, and 69 differentially expressed proteins compared with the DBP group. GO enrichment analysis showed that the differentially expressed proteins mainly include: 60 s acid ribosomal protein P1; nuclear autoantigen sperm protein; centromere protein V; and other proteins related to cell division. These results indicate that MWCNTs with adsorbed DBP can increase oxidative damage in the testis of male mice, interfere with DNA replication and cell division in testicular tissue cells, induce cell apoptosis, and destroy the normal spermatogenic function of the testis.

Exposure to a combination of MWCNTs and DBP causes splenic toxicity in mice.

The large conjugated π bond in the molecular structure of carbon nanotubes (CNTs) interacts with the benzene ring structure in di (n-butyl) phthalates (DBP) through a π - π bond. Compounds of CNTs and DBP form easily, becoming another environmental pollutant of concern. We explore whether CNTs entering animals slow down the degradation of the DBP adsorbed in the CNT cavity, thereby prolonging the "hormonal activity" of DBP. In our study, male BALb/c mice were used as experimental subjects divided into four groups: the control group; the multi-walled carbon nanotubes (MWCNTs) exposure group (10mg/kg/d); the DBP exposure group (2.15 mg/kg/d); and the compound exposure group (MWCNTs + DBP). After 30 days of exposure, the mice were sacrificed and their spleens used for immunotoxicology study. The results showed that the exposure groups exhibited splenomegaly and suffered severe oxidative damage to the spleen. In the compound exposure group: levels of IgA and IgG in the serum of the mice changed, and were significantly different from levels in both the MWCNTs and DBP exposure groups (p <0.05); the pathological sections of the spleen showed that the boundary between the white pulp area (WP) and the red pulp area (RP) was blurred, that the cell arrangement was loose, and that more red blood cells were retained in the spleen. Proteomics mass spectrometry analysis showed that compared with the control group, 70 proteins were up-regulated and 27 proteins were down-regulated in the MWCNTs group, 36 proteins were up-regulated and 23 proteins were down-regulated in the DBP group, 87 proteins were up-regulated and 21 proteins were down-regulated in the compound exposure group. The results of GO enrichment analysis and KEGG enrichment analysis of the differentially expressed proteins showed that the compound exposure harmed the spleen antigen recognition, processing, and presentation, inhibited the activation and proliferation of B cells and T cells, and hindered the adaptive immune responses. Our results showed that MWCNTs and DBP compounds can damage the spleen, and impair the innate and adaptive immune functions of the body.

Learning and memory impairment of mice caused by gaseous formaldehyde.

In order to study the e of formaldehyde exposure on learning and memory ability of mice. We used Kun Ming (KM) mice to demonstrate the neurotoxic effects of FA, and Balb/c mice to explore the neurobiological mechanism. The Morris water maze (MWM) test showed that the exposure of gaseous formaldehyde could cause spatial learning and memory impairment in mice. H & E staining showed that in the 3.0 mg/m3 formaldehyde exposed group, the arrangement of pyramidal cells in CA1 area of mouse hippocampus was loose and disordered, the cell morphology was swollen and deformed, and the apical dendrites were shortened or even disappeared. Biochemical indicators revealed high doses of FA exposure could cause oxidative damage in brain. Compared with the control group, there were significant differences in the levels of ROS, MDA, GSH and 8-OHDG in the 3.0 mg/m3 group (P < 0.01), also the monoamine neurotransmitters content and the content of TNF-α, IL-1ß and Caspase-3 (P < 0.01). Furthermore, the concentrations of cAMP, cGMP, NO and the activity of NOS in the cerebral cortex, hippocampus and brain stem after high doses of FA exposure were significantly different from those in the control group, indicating that FA exposure could interfere with the transduction of NO/cGMP signaling pathway. The results showed that FA could induce cognitive deficits and this extended investigation found that the toxicity of FA to the mouse nervous system is related to the NO/cGMP and cAMP signaling pathways.

Low concentrations of FA exhibits the Hormesis effect by affecting cell division and the Warburg effect.

Formaldehyde (FA), a ubiquitous indoor environmental pollutant, has been classified as a carcinogen. There are many studies showed that low levels of FA could promote cell proliferation, however, little is known about the signal pathways. To determine the potential molecular mechanisms, human chronic myeloid leukemia cells (K562 cells) and human bronchial epithelial cells (16HBE cells) were exposed to different concentrations of FA. The data showed that FA at 0-125 µM or 0-60 µM promoted the proliferation of K562 cells or 16HBE cells respectively, indicating that FA did have the Hormesis effect. FA at 75 µM (K562 cells) and 40 µM (16HBE cells) significantly promoted cell proliferation, increased intracellular reactive oxygen species (ROS) levels, and decreased glutathione (GSH) content. At the same time, FA treatment induced a marked increase in the key molecules of cell division like CyclinD-cdk4 and E2F1. In addition, pyruvate kinase isozyme M2 (PKM2), glucose, glucose transporter 1 (GLUT1), lactic acid and lactate dehydrogenase A (LDHA) content in the Warburg effect were increased. Administering Vitamin E (VE), significantly disrupted cell division and disturbed the Warburg effect, effectively indicating the decrease of cell activity. Conclusively, these findings suggested that low concentrations of FA could promote cell proliferation by accelerating cell division process or enhancing the Warburg effect to embody the Hormesis effect.

Vasodilatory effect of formaldehyde via the NO/cGMP pathway and the regulation of expression of KATP, BKCa and L-type Ca2+ channels.

Formaldehyde (FA), a well-known toxic gas molecule similar to nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S), is widely produced endogenously via numerous biochemical pathways, and has a number of physiological roles in the biosystem. We attempted to investigate the vasorelaxant effects of FA and their underlying mechanisms. We found that FA induced vasorelaxant effects on rat aortic rings in a concentration-dependent manner. The NO/cyclic guanosine 5' monophosphate (cGMP) pathway was up-regulated when the rat aortas were treated with FA. The expression of large-conductance Ca2+-activated K+ (BKCa) channel subunits α and ß of the rat aortas was increased by FA. Similarly, the levels of ATP-sensitive K+ (KATP) channel subunits Kir6.1 and Kir6.2 were also up-regulated when the rat aortas were incubated with FA. In contrast, levels of the L-type Ca2+ channel (LTCC) subunits, Cav1.2 and Cav1.3, decreased dramatically with increasing concentrations of FA. We demonstrated that the regulation of FA on vascular contractility may be via the up-regulation of the NO/cGMP pathway and the modulation of ion channels, including the upregulated expression of the KATP and BKCa channels and the inhibited expression of LTCCs. Further study is needed to explore the in-depth mechanisms of FA induced vasorelaxation.