Time-course and molecular mechanism of hepatotoxicity induced by 1,3-dichloro-2-propanol in rats

Newly discovered developmental and ovarian toxicity of 3-monochloro-1,2-propanediol in Drosophila melanogaster and cyanidin-3-O-glucoside's protective effect

3-Monochloro-1,2-propanediol (3-MCPD) is a pervasive environmental pollutant that is unintentionally produced during industrial production and food processing. Although some studies reported the carcinogenicity and male reproduction toxicity of 3-MCPD thus far, it remains unexplored whether 3-MCPD hazards to female fertility and long-term development. In this study, the model Drosophila melanogaster was employed to evaluate risk assessment of emerging environmental contaminants 3-MCPD at various levels. We found that flies on dietary exposure to 3-MCPD incurred lethality in a concentration- and time-dependent way and interfered with metamorphosis and ovarian development, resulting in developmental retardance, ovarian deformity and female fecundity disorders. Mechanistically, 3-MCPD caused redox imbalance observed as a drastically increased oxidative status in ovaries, confirmed by increased reactive oxygen species (ROS) and decreased antioxidant activities, which is probably responsible for female reproductive impairments and developmental retardance. Intriguingly, these defects can be substantially prevented by a natural antioxidant, cyanidin-3-O-glucoside (C3G), further confirming a critical role of ovarian oxidative damage in the developmental and reproductive toxicity of 3-MCPD. The present study expanded the findings that 3-MCPD acts as a developmental and female reproductive toxicant, and our work provides a theoretical basis for the exploitation of a natural antioxidant resource as a dietary antidote for the reproductive and developmental hazards of environmental toxicants that act via increasing ROS in the target organ.

1,3-Dichloro-2-propanol induced ferroptosis through Nrf2/ARE signaling pathway in hepatocytes

1,3-Dichloro-2-propanol (1,3-DCP) is a representative chloropropane environmental contaminant with multiple toxicities. Ferroptosis is a novel iron-dependent form of regulated cell death that is closely associated with the accumulation of lipid peroxides, Fe²⁺ and reactive oxygen species (ROS). In this study, we found that 1,3-DCP could induce mouse liver injury via ferroptosis. Administrating of C57BL/6J mice with 12.5, 25, and 50 mg/kg 1,3-DCP for 4 weeks via oral gavage, the data showed that 1,3-DCP exposure led to the pathological changes in mouse livers, remarkably induced accumulation of malondialdehyde (MDA) and Iron, reduction of glutathione (GSH), and changed in the expression of ferroptosis marker proteins glutathione peroxidase 4 (GPX4) and acyl-CoA synthetase-4 (ACSL4). Then, we also proved the results with HepG2 cells in vitro. The data showed that treatment 1,3-DCP significantly triggered the ferroptosis in vitro. Furthermore, we found that the ferroptosis-related signal pathways were significantly activated in mice livers and HepG2 cells in response to 1,3-DCP exposure. The data showed that 1,3-DCP induced ferroptosis by inhibiting nuclear factor erythroid 2-related factor 2 (Nrf2) translocation into nuclear and thereby suppressing the expression of its downstream target proteins including GPX4, ferritin heavy chain (FTH), ferroportin (FPN), cystine/glutamate transporter xCT (SLC7A11), and heme oxygenase 1 (HO-1). Taken together, our findings confirmed that 1,3-DCP induced ferroptosis via the Nrf2/ARE signaling pathway in hepatocytes. Our works provide new toxicity mechanisms of 1,3-DCP with ferroptosis on hepatocytes injury.

Korean Red Ginseng Ameliorates Allergic Asthma through Reduction of Lung Inflammation and Oxidation

Six-year-old red ginseng, which is processed from the whole ginseng root via steaming and drying, has been shown to have preventive effects such as antioxidative, anti-inflammatory, and immunomodulatory. In this study, we evaluated the therapeutic effects of Korean red ginseng (KRG) against ovalbumin (OVA)-induced allergic asthma and the underlying mechanisms involved. We injected 20 µg of OVA on days 0 and 14, and mice were challenged with aerosolized OVA via a nebulizer for 1 h on days 21, 22, and 23. KRG was administered at 100 and 300 mg/kg from days 18 to 23. The KRG-treated mice showed significant reductions in their airway hyperresponsiveness, production of reactive oxygen species (ROS), and the number of inflammatory cells compared with the OVA-treated mice. The levels of type 2 cytokines in the bronchoalveolar lavage fluid and expression of OVA-specific immunoglobulin E in the serum, which were elevated in the OVA group, were reduced in the KRG-treated groups. The pro-inflammatory factors, inducible nitric oxide synthase and nuclear factor kappa-light-chain-enhancer of activated B cells, were downregulated by the KRG administration in a dose-dependent manner. KRG effectively suppressed the inflammatory response by inhibiting ROS production. Our results suggest that KRG may have the potential to alleviate asthma.

Diallyl disulfide prevents 1,3-dichloro-2-propanol-induced hepatotoxicity through mitogen-activated protein kinases signaling

We investigated whether diallyl disulfide (DADS) has protective effects against 1,3-dichloro-2-propanol (1,3-DCP)-induced hepatotoxicity and oxidative damage in rats and HepG2 cells. DADS was administered to rats once daily for 7 days at doses of 30 and 60 mg/kg/day. One hour after the final DADS treatment, the rats were administered 90 mg/kg 1,3-DCP to induce acute hepatotoxicity. DADS treatment significantly suppressed the increase in serum aminotransferase levels induced by 1,3-DCP administration, and reduced histopathological alterations in the liver. DADS treatment reduced 1-3-DCP-induced apoptotic changes in the liver, as revealed by terminal deoxynucleotidyl transferase dUTP nick end labeling staining and immunohistochemistry for caspase-3. DADS treatment competitively inhibited or reduced cytochrome p450 2E1 (CYP2E1) expression, which is involved in the metabolic activation of 1,3-DCP, and enhanced antioxidant properties. Furthermore, DADS treatment inhibited phosphorylation of mitogen-activated protein kinases (MAPKs) and apoptotic signaling. In in vitro experiments, MAPKs inhibitors reduced the expression of Bax/Bcl-2/Caspase 3 signaling, which effects were more significant in co-treated cells with DADS and MAPKs inhibitors. In conclusion, the protective effect of DADS against 1,3-DCP-induced hepatotoxicity may be related to blocking the metabolic activation of 1,3-DCP by suppressing CYP2E1 expression, inducing antioxidant enzyme activity, and reducing apoptotic activity by inhibiting phosphorylation of MAPKs.

Rosmarinic Acid Ameliorates H2O2-Induced Oxidative Stress in L02 Cells Through MAPK and Nrf2 Pathways

Liver cells are easily damaged by oxidative stress during progression both in liver development and throughout adult life, resulting in tissue pathology that ranges from simple hepatitis to nonalcoholic fatty liver disease. In this study, we determined the attenuation of oxidative stress in liver cells with pretreatment of rosmarinic acid (RA), which is an antioxidant agent from Rosmarinus officinalis. The human liver cell line L02 was damaged by hydrogen peroxide (H2O2). In the RA treatment group, the viability of L02 cells increased and the intracellular reactive oxygen species levels decreased compared with the H2O2-induced damage group. Analysis of flow cytometry revealed that the percentage of G2/M cell cycle arrest and cell apoptosis decreased in the RA treatment group. This alteration was associated with activation of a G2/M DNA damage and oxidative stress apoptotic signal. Furthermore, we determined the redox-sensitive protein expression of mitogen-activated protein kinases (MAPKs), quinone acceptor oxidoreductase 1 (NQO1), and nuclear factor E2-related factor 2 (Nrf2), and the expression of both MAPKs and Nrf2 was activated in the RA group. Results showed that the relevant protein expression of MAPKs and Nrf2 was activated in the RA group. Thus, RA protected L02 cells from oxidative damage through suppressing cell cycle arrest and cell apoptosis with the activation of MAPK and Nrf2 signaling pathways.

Caffeic acid abrogates 1,3-dichloro-2-propanol-induced hepatotoxicity by upregulating nuclear erythroid-related factor 2 and downregulating nuclear factor-kappa B

1,3-dichloro-2-propanol is a food-borne contaminant reported to cause liver injury. In this study, we evaluated the protective influence of caffeic acid on 1,3-dichloro-2-propanol-induced hepatotoxicity in rats. Rats were randomized into five groups (A-E). Rats received distilled water or caffeic acid (10 or 20 mg/kg body weight) for 7 days. In addition, rats were challenged with 1,3-dichloro-2-propanol on day 7. Caffeic acid prevented 1,3-dichloro-2-propanol-mediated alterations in alkaline phosphatase, alanine and aspartate aminotransferases, albumin and total bilirubin in the serum of rats. Furthermore, caffeic acid lowered superoxide ion, hydrogen peroxide and cytochrome P2E1 while increasing the activities of superoxide dismutase, catalase and glutathione S-transferase in the liver of 1,3-dichloro-2-propanol-treated rats. Caffeic acid raised the levels of nuclear erythroid-related factor 2 (Nrf-2), protein kinase A and phosphoinositide 3-kinase. Caffeic acid pretreatment annulled 1,3-dichloro-2-propanol-mediated alterations in the oxidative stress biomarkers; caspase-3, glutathione, malondialdehyde, protein carbonyl and fragmented DNA, in the liver of rats. Contrastingly, caffeic acid lowered 1,3-dichloro-2-propanol-mediated increase in the levels of nuclear factor-kappa B (NF-κB), tumour necrosis factor-α, interleukin-1β (IL-1β) and IL-6. In addition, caffeic acid preserved the morphological features of 1,3-dichloro-2-propanol-treated rats. Results from this study revealed that caffeic acid protects against 1,3-dichloro-2-propanol-induced hepatotoxicity by enhancing the cytoprotective enzymes through Nrf-2 while lowering inflammation through NF-κB.

Extracts from Erythronium japonicum and Corylopsis coreana Uyeki reduce 1,3-dichloro-2-propanol-mediated oxidative stress in human hepatic cells

In this study, it was demonstrated that 1,3-dichloro-2-propanol (1,3-DCP) induced oxidative stress and cell death in HuH7, human hepatocytes. The protective effects of Erythronium japonicum (E. japonicum) and Corylopsis coreana Uyeki (C. coreana Uyeki) extracts against 1,3-DCP-treated cells were also investigated. First, the activities of superoxide dismutase (SOD) and catalase (CAT) were diminished by the treatment of 1,3-DCP. Moreover, 1,3-DCP stimulated the expression and catalytic activity of cytochrome P450 2E1 (CYP2E1), an enzyme that generates reactive oxygen species in the liver. In contrast, co-treatment of 1,3-DCP with the extracts significantly decreased ROS generation and inhibited CYP2E1 activity without affecting its expression. The co-administration of extracts also restored the activities of SOD and CAT reduced by 1,3-DCP and protected against 1,3-DCP-mediated cell death. In conclusion, these results suggest that 1,3-DCP induces oxidative stress through the elevated CYP2E1 level, which is inhibited by the extracts, protecting cells against the effects of 1,3-DCP.

Dextran‑coated superparamagnetic iron oxide nanoparticles activate the MAPK pathway in human primary monocyte cells

With the increase in applications of superparamagnetic iron oxide nanoparticles (SPIONs) in biomedicine, it is essential to investigate the bio‑security of these nanoparticles, especially with respect to the human immune system. In the present study, the biological effects of dextran‑coated superparamagnetic iron oxide nanoparticles (Dex‑SPIONs) on human primary monocyte cells were evaluated. The results of the present study demonstrated that Dex‑SPIONs can be identified in phagosomes or freed in the cytoplasm and did not affect cell viability or induce apoptosis. Notably, there were certain bulky vacuoles and a number of pseudopodia from the cell membrane, suggesting potential activation of human monocyte cells. In addition, the expression levels of pro‑inflammatory cytokines interleukin (IL)‑1β and tumor necrosis factor (TNF)‑α were also increased following treatment with Dex‑SPIONs. Simultaneously, the phosphorylation levels of mitogen‑activated protein kinase (MAPK) p38, c‑Jun N‑terminal kinase 1 and extracellular signal regulated kinase were markedly enhanced following nanoparticle exposure and MAPK inhibitors could abate the production of IL‑1β and TNF‑α. The results of the present study demonstrated that Dex‑SPIONs could activate human monocyte cells and that activation of MAPK pathway may be involved in these effects.

Copper oxide nanoparticle induces inflammatory response and mucus production via MAPK signaling in human bronchial epithelial cells

Copper nanoparticles (CuONPs) can pose risks to industrial workers. With increase of its applications especially in electronic fields, it is necessary to assess the toxicity of CuONPs, including pulmonary toxicity. In this study, we investigated the effect of CuONPs on human epithelial cell line H292. CuONPs treatment caused a significant increase in IL-6 and IL-8 mRNA expression and protein levels in H292 cells in a concentration-dependent manner. The mRNA expression and protein levels of MUC5AC were consistent with those of proinflammatory mediators. Additionally, CuONPs treatment increased phosphorylation of mitogen-activated protein kinases (MAPKs), Erk, JNK, and p-38 compared to that of control in a concentration-dependent manner. However, co-treatment with CuONPs and each MAPK inhibitor significantly decreased the phosphorylation of each MAPK, resulting in decreased mRNA expression and protein levels of proinflammatory mediators and MUC5AC compared to that in H292 cells only treated with CuONPs. In summary, CuONPs-induced inflammatory mediators and MUC5AC associated with MAPKs phosphorylation. Our results will provide useful information on CuONPs-induced pulmonary toxicity.

Role of mitogen-activated protein kinases and nuclear factor-kappa B in 1,3-dichloro-2-propanol-induced hepatic injury

In this study, the potential hepatotoxicity of 1,3-dichloro-2-propanol and its hepatotoxic mechanisms in rats was investigated. The test chemical was administered orally to male rats at 0, 27.5, 55, and 110 mg/kg body weight. 1,3-Dichloro-2-propanol administration caused acute hepatotoxicity, as evidenced by an increase in serum aminotransferases, total cholesterol, and total bilirubin levels and a decrease in serum glucose concentration in a dose-dependent manner with corresponding histopathological changes in the hepatic tissues. The significant increase in malondialdehyde content and the significant decrease in glutathione content and antioxidant enzyme activities indicated that 1,3-dichloro-2-propanol-induced hepatic damage was mediated through oxidative stress, which caused a dose-dependent increase of hepatocellular apoptotic changes in the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay and immunohistochemical analysis for caspase-3. The phosphorylation of mitogen-activated protein kinases caused by 1,3-dichloro-2-propanol possibly involved in hepatocellular apoptotic changes in rat liver. Furthermore, 1,3-dichloro-2-propanol induced an inflammatory response through activation of nuclear factor-kappa B signaling that coincided with the induction of pro-inflammatory mediators or cytokines in a dose-dependent manner. Taken together, these results demonstrate that hepatotoxicity may be related to oxidative stress-mediated activation of mitogen-activated protein kinases and nuclear factor-kappa B-mediated inflammatory response.