Rebound growth of BRAF mutant pediatric glioma cells after MAPKi withdrawal is associated with MAPK reactivation and secretion of microglia-recruiting cytokines.

INTRODUCTION: Patients with pediatric low-grade gliomas (pLGGs), the most common primary brain tumors in children, can often benefit from MAPK inhibitor (MAPKi) treatment. However, rapid tumor regrowth, also referred to as rebound growth, may occur once treatment is stopped, constituting a significant clinical challenge. METHODS: Four patient-derived pediatric glioma models were investigated to model rebound growth in vitro based on viable cell counts in response to MAPKi treatment and withdrawal. A multi-omics dataset (RNA sequencing and LC-MS/MS based phospho-/proteomics) was generated to investigate possible rebound-driving mechanisms. Following in vitro validation, putative rebound-driving mechanisms were validated in vivo using the BT-40 orthotopic xenograft model. RESULTS: Of the tested models, only a BRAFV600E-driven model (BT-40, with additional CDKN2A/Bdel) showed rebound growth upon MAPKi withdrawal. Using this model, we identified a rapid reactivation of the MAPK pathway upon MAPKi withdrawal in vitro, also confirmed in vivo. Furthermore, transient overactivation of key MAPK molecules at transcriptional (e.g. FOS) and phosphorylation (e.g. pMEK) levels, was observed in vitro. Additionally, we detected increased expression and secretion of cytokines (CCL2, CX3CL1, CXCL10 and CCL7) upon MAPKi treatment, maintained during early withdrawal. While increased cytokine expression did not have tumor cell intrinsic effects, presence of these cytokines in conditioned media led to increased attraction of microglia cells in vitro. CONCLUSION: Taken together, these data indicate rapid MAPK reactivation upon MAPKi withdrawal as a tumor cell intrinsic rebound-driving mechanism. Furthermore, increased secretion of microglia-recruiting cytokines may play a role in treatment response and rebound growth upon withdrawal, warranting further evaluation.

Subchronic exposure to fenpyroximate causes multiorgan toxicity in Wistar rats by disrupting lipid profile, inducing oxidative stress and DNA damage.

BACKGROUND: Fenpyroximate (FEN) is an acaricide that inhibits the complex I of the mitochondrial respiratory chain in mites. Data concerning mammalian toxicity of this acaricide are limited; thus the aim of this work was to explore FEN toxicity on Wistar rats, particularly on cardiac, pulmonary, and splenic tissues and in bone marrow cells. METHODS: rats were treated orally with FEN at 1, 2, 4, and 8 mg/Kg bw for 28 days. After treatment, we analyzed lipid profile, oxidative stress and DNA damage in rat tissues. RESULTS: FEN exposure increased creatinine phosphokinase (CPK) and lactate dehydrogenase (LDH) activities, elevated total cholesterol (T-CHOL), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) concentrations, while decreasing high-density lipoprotein cholesterol (HDL-C). It inhibited acetylcholinesterase (AChE) activity, enhanced lipid peroxidation, protein oxidation, and modulated antioxidant enzymes activities (superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase). Comet assay indicated that FEN induced a dose-dependent DNA damage, contrasting with the micronucleus test showing no micronuclei formation. Nonetheless, FEN exhibited cytotoxicity to bone marrow cells, as evidenced by a reduction in the number of immature erythrocytes among total cells. CONCLUSION: FEN appears to carry out its genotoxic and cytotoxic activities most likely through an indirect pathway that involves oxidative stress.

Oxidative stress-mediated mitochondrial apoptosis induced by the acaricide, fenpyroximate, on cultured human colon cancer HCT 116 cells.

Fenpyroximate (FEN) is an acaricide that inhibits mitochondrial electron transport at the NADH-coenzyme Q oxidoreductase (complex I). The present study was designed to investigate the molecular mechanisms underling FEN toxicity on cultured human colon carcinoma cells (HCT116). Our data showed that FEN induced HCT116 cell mortality in a concentration dependent manner. FEN arrested cell cycle in G0/G1 phase and increased DNA damage as assessed by comet assay. Induction of apoptosis was confirmed in HCT116 cells exposed to FEN by AO-EB staining and Annexin V-FITC/PI double staining assay. Moreover, FEN induced a loss in mitochondrial membrane potential (MMP), increased p53 and Bax mRNA expression and decreased bcl2 mRNA level. An increase in caspase 9 and caspase 3 activities was also detected. All toghether, these data suggest that FEN induce apoptosis in HCT116 cells via mitochondrial pathway. To check the implication of oxidative stress in FEN-induced cell toxicity, we examined the oxidative stress statue in HCT116 cells exposed to FEN and we tested the effect of a powerful antioxidant, N-acetylcystein (NAC), on FEN-caused toxicity. It was observed that FEN enhanced ROS generation and MDA levels and disturbed SOD and CAT activities. Besides, cell treatment with NAC significantly protected cells from mortality, DNA damage, loss of MMP, and caspase 3 activity induced by FEN. To the best of our knowledge, this is the first study showing that FEN induced mitochondrial apoptosis via ROS generation and oxidative stress.

Detection of Methicillin-Resistant Staphylococcus aureus among Foodborne Pathogenic Strains and Assessment of Their Adhesion Ability and Cytotoxic Effects in HCT-116 Cells.

Staphylococcus aureus is one of the high-threat pathogens equipped with a repertoire of virulence factors making it responsible for many infections in humans, including foodborne diseases. The present study aims to characterize antibiotic resistance and virulence factors in foodborne S. aureus isolates, and to investigate their cytotoxic effects in human intestinal cells (HCT-116). Our results revealed methicillin resistance phenotypes (MRSA) along with the detection of mecA gene (20%) among tested foodborne S. aureus strains. Furthermore, 40% of tested isolates showed a strong ability for adhesion and biofilm formation. A high rate of exoenzymes production by tested bacteria was also registered. Additionally, treatment with S. aureus extracts leads to a significant decrease in HCT-116 cell viability, accompanied by a reduction in the mitochondrial membrane potential (MMP), as a result of reactive oxygen species (ROS) generation. Thereby, S. aureus food poisoning remains daunting and needs particular concern to prevent foodborne illness.

Genotoxic damage and apoptosis in rat glioma (F98) cell line following exposure to bromuconazole.

Bromuconazole, a fungicide from the triazole family, is widely used to protect the crop from various fungal contaminations to increase product quality and productivity. Although the massive use of bromuconazole poses a serious risk to human health, the exact mechanism of bromuconazole toxicity, especially on brain support cells, called glia cells, remains unclear so far. This study aimed to determine the mechanism of cytotoxicity and genotoxicity of bromuconazole via inspection of apoptotic death in rat glioma (F98) cells. We observed that bromuconazole treatment caused concentration-dependent cell death with an IC50 of 60 µM, and disruption of the cytoskeleton was observed via immunocytochemical analysis. Further, bromuconazole inhibits cell proliferation, it arrests the cell cycle in the G0/G1 phase and so inhibits DNA synthesis. Genotoxic analysis showed that bromuconazole exposition causes DNA fragmentation (comet assay) and nuclear condensation (DAPI staining). Apoptotic cell death was confirmed through: positive Annexin-V/FITC-PI dyes, p53 and Bax overexpression, Bcl2 repression, an increase in Bax/BCL-2 ratios of the mRNA, mitochondrial membrane depolarization, and an increase of caspase-3 activity. All these results demonstrate that bromuconazole exerts its cytotoxic and genotoxic effects through apoptotic cell death, which could implicate mitochondria.

Fludioxonil, a phenylpyrrol pesticide, induces Cytoskeleton disruption, DNA damage and apoptosis via oxidative stress on rat glioma cells.

Pesticides products are widely used to increase food productivity and to decrease food-borne diseases. Fludioxonil is a worldwide used phenylpyrrol fungicide. This pesticide can induce serious effects on human health especially on nervous system. We assessed the role of oxidative stress in the toxicity of Fludioxonil and examined its apoptotic mechanism of action on rat neural cells (F98). We have shown that the increasing concentration of Fludioxonil reduces the percentage of living F98 cells viability and increases the levels of reactive oxygen species and malondialdheydes. The reduction of cells proliferation was demonstrated with an accumulation in G2/M phase. The immunocytochemical analysis has shown that Fludioxonil induced the disruption of the cytoskeleton. DNA damage was also provoked in a concentration dependent manner as illustrated by the comet assay. The depolarization of the mitochondria and the positive Annexin V FITC-PI confirmed the apoptosis induced by this fungicide. Interestingly, the F98 cells viability and ROS levels were restored with N-acetylcysteine pre-treatment. These results highlight the involvement of oxidative stress in the toxicity induced by this fungicide, and that free radicals generation plays a key role in the induction of apoptosis probably induced via the mitochondrial pathway.

Bromuconazole fungicide induces cell cycle arrest and apoptotic cell death in cultured human colon carcinoma cells (HCT116) via oxidative stress process.

BACKGROUND: Bromuconazole, a fungicide belonging to the triazole family, is a plant protection product used to control, repel or destroy fungi that may develop on crops. We investigated the pro-apoptotic effect of bromuconazole and the role of oxidative stress in the death mechanism induced by this fungicide in this study. METHODS: The human colon HCT116 cell line was treated with Bromuconazole (IC50/4, IC50/2, and IC50) for 24 h. Cells were collected and analysed for biomarkers of apoptotic cell death and oxidative stress as well as for the assessment of genotoxic damage. RESULTS: Our study showed that bromuconazole caused a concentration-dependent increase in cell mortality with an IC50 of 180 µM. Bromuconazole induced cell cycle arrest in the G0/G1 phase and DNA synthesis inhibition. The Comet assay showed that bromuconazole caused DNA damage in a concentration-dependent manner. Bromuconazole-induced apoptosis was observed by, Annexin-V/FITC-PI and BET/AO staining, by mitochondrial membrane depolarisation, and by increased caspase-3 activity. In addition, bromuconazole induced a significant increase in ROS and lipid peroxidation levels and a disruption in SOD and CAT activities. N-acetylcysteine (NAC) strongly prevents cytotoxic and genotoxic damage caused by bromuconazole. CONCLUSION: Bromuconazole toxicity was through the oxidative stress process, which causes DNA damage and mitochondrial dysfunction, leading to cell cycle arrest and apoptotic death of HCT116 cells.

Bromuconazole exposure induced cell cycle arrest in the G0/G1 in HCT116 cells.Bromuconazole caused DNA synthesis inhibition and degradation.Bromuconazole-induced Annexin-V/FITC-PI and BET/AO positive staining, increased caspase-3 activity and MMP.Bromuconazole enhances ROS, MDA levels and disruption of CAT and SOD activities.

Evaluation of hepatotoxicity and nephrotoxicity induced by fenpyroximate in subchronic-orally exposed Wistar rats.

BACKGROUNDS: Fenpyroximate (FEN) is an acaricide that inhibits the complex I of the mitochondrial respiratory chain. The aim of this work was to explore the hepatotoxic and nephrotoxic effects of FEN on Wistar rats. METHODS: The study involved five groups: a control group and four groups treated with FEN at 1, 2, 4, and 8 mg/Kg bw for 28 consecutive days. Histological examination and biochemical analysis of hepatic and renal biomarkers were performed. The malondialdehyde (MDA), protein carbonyl levels, and antioxidant enzymes activities were measured. Comet assay was conducted to explore FEN genotoxicity. RESULTS: FEN induced a disturbance of the hepatic and renal functions as evidenced by an increase in AST, ALT, ALP, creatinine, and uric acid levels and histopathological modifications in the two examined tissues. FEN increased hepatic and renal lipid peroxidation and protein oxidation. The activities of liver and kidney SOD, CAT, GPX, and GST are increased significantly in FEN-treated rats at doses of 2 and 4 mg/kg bw. However, with the dose of 8 mg/kg bw of FEN, these activities are decreased. Moreover, FEN increased DNA damage in a dose-dependent manner. CONCLUSION: FEN was hepatotoxic and nephrotoxic very likely through induction of oxidative stress.

Brain injury, genotoxic damage and oxidative stress induced by Bromuconazole in male Wistar rats and in SH-SY5Y cell line.

BACKGROUND: Bromuconazole is a widely used triazole against various fungi disease. It's employment provokes harmful effects on the environment and human health. In the present study, we explored bromuconazole toxic effects in both rat brain tissue and SH-SY5Y cell line. METHODS: Male Wistar rats were administrated orally with Bromuconazole (NOEL/4, NOEL o and NOEL ×2) daily for consecutive 28 days. In addition, neuronal SH-SY5Y cell line was used. The rat brains and SH-SY5Y cells were collected and analysed for AChE activity, oxidative stress biomarkers, genotoxicity and histopathological alterations. RESULTS: Our results showed that rat exposure to bromuconazole at doses corresponding to NOEL/4, NOEL and NOEL ×2 caused brain histopathological alteration and decrease in acetylcholine esterase (AChE) activity. In SH-SY5Y cell line, bromuconazole strongly induced cell mortality with an IC50 about 250 µM. Bromuconazole induced also DNA damage as assessed by comet assay in both rat brain tissue and SH-SY5Y cell. Moreover, bromuconazole increased ROS production, malondialdehyde (MDA) and protein carbonyl (PC) levels and enhanced the enzymatic activities of catalase (CAT), superoxide dismutase (SOD), Glutathione-S-transferase (GST) and peroxidase (GPx) in the two studied systems. CONCLUSION: Therefore, we can deduce that bromuconazole-caused neurotoxicity may be related to oxidative statue disturbance.HIGHLIGHTSBromuconzole causes oxidative stress in the brain tissue of male Wistar rats.Bromuconazole enhances MDA, PC levels and induces DNA damage in rat brain.Bromuconazole provokes disturbance of the neuronal antioxidant system.Bromuconazole induces histopathological alterations in rat brain.Bromuconazole exposure induced cytotoxic effects and DNA damage in SH-SY5Y cells.Bromuconazole exposure induced oxidative stress in SH-SY5Ycells.

Fenpyroximate induced cytotoxicity and genotoxicity in Wistar rat brain and in human neuroblastoma (SH-SY5Y) cells: Involvement of oxidative stress and apoptosis.

Fenpyroximate (FEN) is an acaricide used in agriculture / horticulture to control spider mites and leafhoppers. It inhibits the transport of mitochondrial electrons at the level of NADH-coenzyme Q oxidoreductase (complex I). Despite the implication of inhibition of mitochondrial complex I in neurotoxicity, especially in neurodegenerative diseases, data concerning FEN neurotoxicity remain limited. Thus, the present study was designed to investigate the toxic effect of FEN on rat brain tissue and on human neuroblastoma cells (SH-SY5Y). Rat exposure to FEN at three different doses (4.8, 9.6 and 48 mg / Kg bw) for 28 consecutive days resulted in histopathological modifications in brain tissue and a significant decrease in acetylcholinesterase activity. Further, FEN significantly enhanced lipid peroxidation and protein oxidation in rat brain and disturbed activities of antioxidant enzymes (SOD, CAT, GPx, and GST). Besides, FEN was found to induce DNA damage in a significant and dose-dependent manner in rat brain as assessed by the comet assay. To better understand FEN neurotoxic effect, we monitored our study on SH-SY5Y cells. We confirm our data found in rat brain tissue. In fact, FEN induced cell mortality in a concentration dependent manner. It over-produced intracellular ROS and lipid peroxidation and enhanced SOD and CAT activities. FEN was also found to induce DNA damage in SH-SY5Y cells. Moreover, FEN induced a loss of mitochondrial membrane potential, which confirms FEN mitochondrial impairing activity. Acridine Orange-Bromure Etidium (AO-BE) cell staining indicated that FEN enhanced the percentage of apoptotic cells in a concentration dependent manner. Further, pretreatment with a general caspases inhibitor (ZVAD-FMK), reduced significantly the FEN induced cell mortality. We also shown that FEN increased caspase 3 activity. These findings suggested, for the first time, the possibility of the involvement of mitochondrial pathway in FEN-induced cell apoptosis.

Subchronic exposure to Epoxiconazole induced-heart damage in male Wistar rats.

Epoxiconazole is a worldwide fungicide used to control fungal diseases. Although to its hazardous effects in non-target species, little information is available in the literature to show the cardiotoxic effects of EPX in male rats. Thus, our investigation aimed to assess the outcomes of EPX exposure on some biochemical parameters, the generation of oxidative stress, DNA fragmentation and histopathological alterations in the heart tissue. EPX was administered orally at doses of 8, 24, 40 and 56 mg/kg body weight, representing, respectively NOEL (No observed effect level), NOEL× 3, NOEL× 5 and NOEL× 7 for 28 consecutive days in male Wistar rats. Our results show that EPX induced a significant decrease of cardiac acetylcholinesterase, an increase of biochemical markers, such as creatinine phosphokinase (CPK) and a perturbation of the lipid profile. Furthermore, EPX caused diverse histological modifications in the myocardium, including congestion of cardiac blood vessels, cytoplasmic vacuolization, leucocytic infiltration and hemorrhage. Indeed, we have shown that EPX induces increase of lipid peroxidation, protein oxidation levels and DNA damage. On the other hand, we have found an increase of the antioxidant enzymes activity such as catalase (CAT) and superoxide dismutase (SOD) activities. The glutathione peroxidase and glutathione S tranferase initially enhanced at the doses of 8, 24, and 40 mg/kg b.w. and then decreased at the dose of 56 mg/kg b.w. In conclusion, our work has shown that EPX causes cardiotoxic effects by altering redox status and damaging heart tissue.

Epoxiconazole caused oxidative stress related DNA damage and apoptosis in PC12 rat Pheochromocytoma.

Epoxiconazole is among the most widely applied pesticides worldwide. The increased use of these products could cause toxic effects on human health which are mainly associated with its residues in food or occupational exposure in agriculture. The brain is the principal target of lipophilic compounds exposure, while the data of brain injury induced by Epoxiconazole remains unclear. The purpose of our investigation was to assess the cytotoxic and genotoxic effects of the epoxiconazole in rat Pheochromocytoma (PC 12). We found that epoxiconazole could reduce the viability and proliferation of PC12 cells, induce the DNA damage, nuclear condensation, cytoskeleton network disruption and enhance the apoptotic cell death. Intracellular biochemical assay proved that EPX induces the loss of mitochondrial membrane potential (ΔΨm) and activates caspase-3. Indeed, EPX instigated ROS generation in neuronal cells, which is accompanied by an increase of lipid peroxidation as confirmed by the high levels of MDA. Interestingly, Pre-treatment of PC12 cells with the ROS scavenger N-acetylcysteine mitigated EPX-provoked DNA fragmentation and enhancement of apoptosis. Our results demonstrate that the genotoxic and cytotoxic outcomes of EPX are mediated through a ROS-dependent pathway in PC12 cells.

Bromuconazole caused genotoxicity and hepatic and renal damage via oxidative stress process in Wistar rats.

Bromuconazole is a triazole pesticide used to protect vegetables and fruits against diverse fungi pathologies. However, its utilization may be accompanied by diverse tissue injuries. In this study, we evaluated the biochemical and histopathological modifications, and we analyzed genotoxic and oxidative stress, in the aim to examine bromuconazole effects in the liver and kidney. We subdivided animals into four groups, each one contains six adult male Wistar rats. Untreated rats received daily a corn oil (vehicle) orally. Three oral bromuconazole doses were tested (1, 5, and 10 % of LD50) daily for 28 days. Bromuconazole increased the plasma activities of alkaline phosphatase, lactate dehydrogenase, and transaminases. It also increased the plasma levels of creatinine and uric acid. Histopathological check showed that bromuconazole caused organ damage. This study makes known that bromuconazole caused conspicuous DNA damage either in hepatic or kidney tissues, with a significant increase in the levels of malondialdehyde and protein carbonyl followed by an enhancement in catalase and superoxide dismutase enzymatic activities, and these increases are in a dose-dependent manner. In other side, we found that Glutathione-S-transferase and peroxidase activities raised. Our outcomes highlight that bromuconazole exposure induced genotoxic damage and organ damage which may be caused by the disturbances of oxidative stress statue in the liver and kidney.

Epoxiconazole profoundly alters rat brain and properties of neural stem cells.

Epoxiconazole (EPX), a widely used fungicide for domestic, medical, and industrial applications, could cause neurodegenerative diseases. However, the underling mechanism of neurotoxicity is not well understood. This study aimed to investigate the possible toxic outcomes of Epoxiconzole, a triazole fungicide, on the brain of adult rats in vivo, and in vitro on neural stem cells derived from the subventricular zone of newborn Wistar rats. Our results revealed that oral exposure to EPX at these concentrations (8, 24, 40, 56 mg/kg bw representing respectively NOEL (no observed effect level), NOEL × 3, NOEL × 5, and NOEL × 7) for 28 days caused a considerable generation of oxidative stress in adult rat brain tissue. Furthermore, a significant augmentation in lipid peroxidation and protein oxidation has been found. Moreover, it induced an elevation of DNA fragmentation as assessed by the Comet assay. Indeed, EPX administration impaired activities of antioxidant enzymes and inhibited AChE activity. Concomitantly, this pesticide produced histological alterations in the brain of adult rats. Regarding the embryonic neural stem cells, we demonstrated that the treatment by EPX reduced the viability of cells with an IC50 of 10 µM. It also provoked the reduction of cell proliferation, and EPX triggered arrest in G1/S phase. The neurosphere formation and self-renewal capacity was reduced and associated with decreased differentiation. Moreover, EPX induced cytoskeleton disruption as evidenced by immunocytochemical analysis. Our findings also showed that EPX induced apoptosis as evidenced by a loss of mitochondrial transmembrane potential (ΔΨm) and an activation of caspase-3. In addition, EPX promoted ROS production in neural stem cells. Interestingly, the pretreatment of neural stem cells with the N-acetylcysteine (ROS scavenger) attenuated EPX-induced cell death, disruption of neural stem cells properties, ROS generation and apoptosis. Thus, the use of this hazardous material should be restricted and carefully regulated.

Tebuconazole induced cytotoxic and genotoxic effects in HCT116 cells through ROS generation.

Tebuconazole (TEB) is a common triazole fungicide that has been widely used for the control of plant pathogenic fungi, suggesting that mammal exposure occurs regularly. Several studies demonstrated that TEB exposure has been linked to a variety of toxic effects, including neurotoxicity, immunotoxicity, reprotoxicity and carcinogenicity. However, there is a few available data regarding the molecular mechanism involved in TEB-induced toxicity. The current study was undertaken to investigate the toxic effects of TEB in HCT116 cells. Our results showed that TEB caused cytotoxicity by inhibiting cell viability as assessed by the MTT assay. Furthermore, we have demonstrated that TEB induced a significant increase in the reactive oxygen species (ROS) production leading to the induction of lipid peroxidation and DNA fragmentation and increased superoxide dismutase (SOD) and catalase (CAT) activities. Moreover, TEB exposure induced mitochondrial membrane potential loss and caspase-9/-3 activation. Treatment with general caspases inhibitor (Z-VAD-fmk) significantly prevented the TEB-induced cell death, indicating that TEB induced caspases-dependent cell death. These findings suggest the involvement of oxidative stress and apoptosis in TEB-induced toxicity in HCT116.

Neuroprotective effects of Myricetin on Epoxiconazole-induced toxicity in F98 cells.

Epoxiconazole is one of the most commonly used fungicides in the world. The exposition of humans to pesticides is mainly attributed to its residue in food or occupational exposure in agricultural production. Because of its lipophilic character, Epoxiconazole can accumulate in the brain Heusinkveld et al. (2013) [1]. Consequently, it is urgent to explore efficient strategies to prevent or treat Epoxiconazole-related brain damages. The use of natural molecules commonly found in our diet represents a promising avenue. Flavonoids belong to a major sub-group compounds possessing powerful antioxidant activities based on their different structural and sterical properties [2]. We choose to evaluate Myricetin, a flavonoid with a wide spectrum of pharmacological effects, for its possible protective functions against Epoxiconazole-induced toxicities. The cytotoxicity induced by this fungicide was evaluated by the cell viability, cell cycle arrest, ROS generation, antioxidant enzyme activities, and Malondialdehyde production, as previously described in Hamdi et al., 2019 [3]. The apoptosis was assessed through the evaluation of the mitochondrial transmembrane potential (ΔΨm), caspases activation, DNA fragmentation, cytoskeleton disruption, nuclear condensation, appearance of sub-G0/G1 peak (fragmentation of the nucleus) and externalization of Phosphatidylserine. This study indicates that pre-treatment of F98 cells with Myricetin during 2 h before Epoxiconazole exposure significantly increased the survival of cells, restored DNA synthesis of the S phase, abrogated the ROS generation, regulated the activities of Catalase (CAT) and Superoxide Dismutase (SOD), and reduced the MDA level. The loss of mitochondrial membrane potential, DNA fragmentation, cytoskeleton disruption, chromatin condensation, Phosphatidylserine externalization, and Caspases activation were also reduced by Myricetin. Together, these findings indicate that Myricetin is a powerful natural product able to protect cells from Epoxiconazole-induced cytotoxicity and apoptosis.

Tebuconazole induced oxidative stress and histopathological alterations in adult rat heart.

TEB belongs to the family of triazole fungicides and it is used to protect agricultural crop plants from fungal pathogens. The information regarding its cardiotoxic effects through different pathways particularly by perturbing the oxidative balance and causing damage to the myocardium is still limited. In the present study, oxidative and histopathologic damages caused by TEB in the cardiac tissue of male adult rats, were evaluated. Rats were exposed orally to TEB at 0.9, 9, 27 and 45 mg/kg b.w. for 28 days. Results showed that following TEB treatment malondialdehyde (MDA), protein carbonyl (PC), advanced oxidation protein product (AOPP), antioxidant enzyme activities (GPx and GR) and GSSG levels increased, while GSH levels and thus the GSH/GSSG ratio decreased. Superoxide dismutase (SOD) and catalase (CAT) initially increased at the doses of 0.9, 9 and 27 mg/kg b.w. and then decreased at the dose of 45 mg/kg b.w. Moreover, western blot analysis showed that TEB increased SOD1, CAT and HSP70 protein levels after 24 h. Furthermore, TEB induced various histological changes in the myocardium, including leucocytic infiltration, hemorrhage congestion of cardiac blood vessels and cytoplasmic vacuolization. Therefore, our investigation revealed, that TEB exhibits cardiotoxic effects by changing oxidative balance and damaging the cardiac tissue.

Oxidative stress, DNA damage and apoptosis induced by tebuconazole in the kidney of male Wistar rat.

Tebuconazole (TEB) is a broad-spectrum conazole fungicide that has been used in agriculture in the control of foliar and soil-borne diseases of many crops. The present study has investigated the adverse effects of subchronic exposure to TEB on the kidney of male rats. Animals were divided into four equal groups and treated with TEB at increasing doses 0.9, 9 and 27 mg/kg body weight for 28 consecutive days. The results showed that TEB induced oxidative stress in the kidney demonstrated by an increase in malondialdehyde (MDA), protein carbonyl (PC), advanced oxidation protein product (AOPP) levels and DNA damage, as compared to the controls. Furthermore, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities were increased in the renal tissue of treated rats. Moreover, significant decrease in reduced glutathione (GSH) content in TEB-treated rats was observed, while oxidized glutathione (GSSG) levels were increased, thus a marked fall in GSH/GSSG ratio was registered in the kidney. Glutathione reductase (GR) activity showed a significant increase after TEB exposure. Moreover, TEB down-regulated the expression of Bcl2 and up-regulated the expression of Bax and caspase 3, which triggered apoptosis via the Bax/Bcl2 and caspase pathway. Also, TEB administration resulted in altered biochemical indicators of renal function and varying lesions in the overall histo-architecture of renal tissues. Taken together, our findings brought into light the renal toxicity induced by TEB, which was found to be significant at low doses.

Tebuconazole induced cardiotoxicity in male adult rat.

Tebuconazole is an effective systemic fungicide that belongs to the triazoles family. It has been widely used in both agricultural and medical sectors for the control of fungal diseases. Although TEB poses serious threats to mammals health, studies regarding its cardiotoxicity are very limited. Thus, we aimed to evaluate the effects of TEB on some biochemical parameters, the induction of apoptosis and DNA damage in the heart tissue. Male Wistar rats were treated with TEB at varied oral doses for 28 consecutive days. This study demonstrates that TEB decreased cardiac acetylcholinesterase, increased serum marker enzymes such as creatinine phosphokinase (CPK) and lactate dehydrogenase (LDH), and altered the lipid profile by increasing serum levels of total cholesterol (T-CHOL), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and reduced high-density lipoprotein cholesterol (HDL-C) levels. Furthermore, TEB increased levels of p53 and Bax/Bcl2 ratio, released the cytochrome c into the cytosol and activated caspase-9 and caspase-3. Besides, our results showed that TEB induced genotoxic effects. TEB induced DNA fragmentation and increased the frequency of micronucleated bone marrow cells. Moreover, TEB treatment developed fibrosis in the myocardium. Our results suggest that TEB exposure may affect myocardial cells normal functioning and triggers apoptosis.

Cytotoxic and genotoxic effects of epoxiconazole on F98 glioma cells.

Epoxiconazole (EPX) is a very effective fungicide of the triazole family. Given its wide spectrum of use, the increased application of this pesticide may represent a serious risk on human health. Previous studies have found that EPX is cytotoxic to cells, although the exact mechanism remains elusive. In particular, the effect on the nervous system is poorly elucidated. Here we evaluated the implication of oxidative stress in the neurotoxicity and studied its apoptotic mechanism of action. We demonstrated that the treatment by EPX reduces the viability of cells in a dose dependent manner with an IC50 of 50 µM. It also provokes the reduction of cell proliferation. EPX could trigger arrest in G1/S phase of cell cycle with low doses, however with IC50, it induced an accumulation of F98 cells in G2/M phase. Moreover, EPX induced cytoskeleton disruption as evidenced by immunocytochemical analysis. It provoked also DNA fragmentation in a concentration dependent manner. The EPX induced apoptosis, which was observed by morphological changes and by positive Annexin V FITC-PI staining concurrent with a depolarization of mitochondria. Furthermore, the cell mortality provoked by EPX was significantly reduced by pretreatment with Z-VAD-FMK, a caspase inhibitor. Moreover, N-acetylcysteine (NAC) strongly restores cell viability that has been inhibited by EPX. The results of these findings highlight the implication of ROS generation in the neurotoxicity induced by EPX, indicating that the production of ROS is the main cause of the induction of apoptosis probably via the mitochondrial pathway.