Taurine Alleviate Hexabromocyclododecane-Induced Cytotoxicity in PC12 Cells via Inhibiting Oxidative Stress

Investigation of the mechanisms behind ochratoxin A-induced cytotoxicity in human astrocytes and the protective effects of N-acetylcysteine

Ochratoxin A (OTA) is a type of mycotoxin commonly found in raw and processed foods. It is essential to be aware of this toxin, as it can harm your health if consumed in high quantities. OTA can induce toxic effects in various cell models. However, a more comprehensive understanding of the harmful effects of OTA on human astrocytes is required. This study evaluated OTA's neurotoxic effects on the Gibco® Human Astrocyte (GHA) cell line, its underlying mechanisms, and the antioxidant N-acetylcysteine (NAC) ability to prevent them. OTA exposure within 5-30 μM has induced concentration-dependent cytotoxicity. In the OTA-treated cells, the levels of reactive oxygen species (ROS) were found to be significantly increased, while the glutathione (GSH) contents were found to decrease considerably. The western blotting of OTA-treated cells has revealed increased Bax, cleaved caspase-9/caspase-3 protein levels, and increased Bax/Bcl-2 ratio. In addition, exposure to OTA has resulted in the induction of antioxidant responses associated with the protein expressions of Nrf2, HO-1, and NQO1. On the other hand, the pretreatment with NAC has partially alleviated the significant toxic effects of OTA. In conclusion, our findings suggest that oxidative stress and apoptosis are involved in the OTA-induced cytotoxicity in GHA cells. NAC could act as a protective agent against OTA-induced oxidative damage.

Involvement of oxidative stress-related apoptosis in chlorpyrifos-induced cytotoxicity and the ameliorating potential of the antioxidant vitamin E in human glioblastoma cells

Organophosphate pesticides (OPs), which are among the most widely used synthetic chemicals for the control of a wide variety of pests, are however associated with various adverse reactions in animals and humans. Chlorpyrifos, an OP, has been shown to cause various health complications due to ingestion, inhalation, or skin absorption. The mechanisms underlying the adverse effect of chlorpyrifos on neurotoxicity have not been elucidated. Therefore, we aimed to determine the mechanism of chlorpyrifos-induced cytotoxicity and to examine whether the antioxidant vitamin E (VE) ameliorated these cytotoxic effects using DBTRG-05MG, a human glioblastoma cell line. The DBTRG-05MG cells were treated with chlorpyrifos, VE, or chlorpyrifos plus VE and compared with the untreated control cells. Chlorpyrifos induced a significant decrease in cell viability and caused morphological changes in treated cultures. Furthermore, chlorpyrifos led to the increased production of reactive oxygen species (ROS) accompanied by a decrease in the level of reduced glutathione. Additionally, chlorpyrifos induced apoptosis by upregulating the protein levels of Bax and cleaved caspase-9/caspase-3 and by downregulating the protein levels of Bcl-2. Moreover, chlorpyrifos modulated the antioxidant response by increasing the protein levels of Nrf2, HO-1, and NQO1. However, VE reversed the cytotoxicity and oxidative stress induced by chlorpyrifos treatment in DBTRG-05MG cells. Overall, these findings suggest that chlorpyrifos causes cytotoxicity through oxidative stress, a process that may play an important role in the development of chlorpyrifos-associated glioblastoma.

Tetrabromobisphenol A and hexabromocyclododecane, brominated flame retardants, trigger endoplasmic reticulum stress and activate necroptosis signaling in PC12 cells

Tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCD) are brominated flame retardants commonly used in a variety of industrial and consumer products. In this study, we performed RNA sequencing analysis of PC12 cells to clarify the mechanisms by which TBBPA and HBCD induce neurotoxicity. Differential expression analysis demonstrated that 636 and 271 genes were differentially expressed after TBBPA and HBCD treatment, respectively. Gene Ontology (GO) enrichment analysis revealed that genes annotated with the GO term "endoplasmic reticulum unfolded protein response" were upregulated in both TBBPA- and HBCD-treated groups. Furthermore, protein expression of endoplasmic reticulum stress markers, such as HSPA5 and DDIT3, as well as cleaved caspase-3, an apoptosis marker, were induced by TBBPA and HBCD. We also found that the cytotoxicity induced by TBBPA and HBCD was blocked by necrostatin-1, a necroptosis inhibitor, indicating the contribution of necroptosis. Our findings provide new insight into the mechanisms of toxicity induced by these chemicals.

Investigation of Cytotoxicity and Oxidative Stress Induced by the Pyrethroid Bioallethrin in Human Glioblastoma Cells: The Protective Effect of Vitamin E (VE) and Its Underlying Mechanism

Bioallethrin belongs to the family of pyrethroid insecticides. Previous studies have shown that bioallethrin affected the function of muscarinic receptor and subsequently induced neurotoxicity in different brain models. Reactive oxygen species (ROS) are generated in the metabolic course of the human body, which can cause human damage when overactivated. However, whether bioallethrin evokes cytotoxicity through ROS signaling and whether the antioxidant Vitamin E (VE) protects these cytotoxic responses in human glial cell model are still elusive. This study investigated the effect of bioallethrin on cytotoxicity through ROS signaling and evaluated the protective effect of the antioxidant VE in DBTRG-05MG human glioblastoma cells. The cell counting kit-8 (CCK-8) was used to measure cell viability. Intracellular ROS and glutathione (GSH) levels were measured by a cellular assay kit. The levels of apoptosis- and antioxidant-related protein were analyzed by Western blotting. In DBTRG-05MG cells, bioallethrin (25-75 μM) concentration-dependently induced cytotoxicity by increasing ROS productions, decreasing GSH contents, and regulating protein expressions related to apoptosis or antioxidation. Furthermore, these cytotoxic effects were partially reversed by VE (20 μM) pretreatment. Together, VE partially lessened bioallethrin-induced apoptosis through oxidative stress in DBTRG-05MG cells. The data assist us in identifying the toxicological mechanism of bioallethrin and offer future development of the antioxidant VE to reduce brain damage caused by bioallethrin.

Update of the risk assessment of hexabromocyclododecanes (HBCDDs) in food

The European Commission asked EFSA to update its 2011 risk assessment on hexabromocyclododecanes (HBCDDs) in food. HBCDDs, predominantly mixtures of the stereoisomers α-, β- and γ-HBCDD, were widely used additive flame retardants. Concern has been raised because of the occurrence of HBCDDs in the environment, food and in humans. Main targets for toxicity are neurodevelopment, the liver, thyroid hormone homeostasis and the reproductive and immune systems. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour in mice can be considered the critical effects. Based on effects on spontaneous behaviour in mice, the Panel identified a lowest observed adverse effect level (LOAEL) of 0.9 mg/kg body weight (bw) as the Reference Point, corresponding to a body burden of 0.75 mg/kg bw. The chronic intake that would lead to the same body burden in humans was calculated to be 2.35 μg/kg bw per day. The derivation of a health-based guidance value (HBGV) was not considered appropriate. Instead, the margin of exposure (MOE) approach was applied to assess possible health concerns. Over 6,000 analytical results for HBCDDs in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary LB exposure to HBCDDs were fish meat, eggs, livestock meat and poultry. The CONTAM Panel concluded that the resulting MOE values support the conclusion that current dietary exposure to HBCDDs across European countries does not raise a health concern. An exception is breastfed infants with high milk consumption, for which the lowest MOE values may raise a health concern.