Liver histopathological and oxidative stress assessment by a combination of formaldehyde and oxytetracycline in sea bass (Dicentrarchuslabrax L).

Background: Formaldehyde (FA) and oxytetracycline (OTC) are the chemicals commonly used in aquaculture to prevent or treat fish diseases due to protozoa, parasites, and bacteria. Aim: The goal of the present study is to assess the liver injury and oxidative stress induced by exposure of sea bass (Dicentrarchuslabrax L) to therapeutic doses of FA (200 ml.m-3) and OTC (40 g.m-3) under the same conditions being applied in intensive aquaculture systems in Tunisia. Methods: The liver histopathological survey was achieved after 5 and 10 days of exposure to FA, OTC separately or mixed. In parallel, liver catalase activity and malondialdehyde (MDA) were measured to assess oxidative stress. Results: Results showed that treatment with FA and OTC used alone or in combinations induced liver damage as measured by sinusoid dilatation, intensive vacuolization, blood congestion, and focal necrosis. Significant elevation in catalyze activity and MDA levels were also observed in liver homogenates by the treatment (p ≤ 005). Conclusion: Combined treatment induced higher effects suggesting the critical hazards associated with FA and OTC when released to the environment.

The protective effects of thymol and carvacrol against di (2-ethylhexyl) phthalate-induced cytotoxicity in HEK-293 cells.

The protective effects of thymol and carvacrol, two phenolic monoterpenes with a wide spectrum of pharmacological effects, against the oxidative stress produced by the di (2-ethylhexyl) phthalate (DEHP) in human embryonic kidney cells 293 cells (HEK-293 cells) were investigated in this study. The cytotoxicity was monitored by cell viability, while oxidative stress generation was assessed by reactive oxygen species (ROS) quantification, antioxidant enzyme activities measurement, glutathione concentration, and malondialdehyde (MDA) quantification. The genotoxicity was evaluated by the measurement of DNA fragmentation through the Comet assay. Our results demonstrated that the pretreatment of HEK-293 cells with thymol or carvacrol, 2 h before DEHP exposure, significantly increased the cell viability, decreased the ROS overproduction, modulated catalase (CAT), and superoxide dismutase (SOD) activities, restored the reduced glutathione content, and reduced the MDA level. The DNA fragmentation was also decreased by thymol and carvacrol pretreatment. These findings suggest that thymol and carvacrol could protect HEK-293 cells from DEHP-induced oxidative stress.

Effect of di(2-ethylhexyl) phthalate on Nrf2-regulated glutathione homeostasis in mouse kidney.

Environmental toxicants such as phthalate have been involved in multiple health disorders including renal diseases. Oxidative damage is implicated in many alterations caused by phthalate especially the di(2-ethylhexyl) phthalate (DEHP), which is the most useful phthalate. However, information regarding its mechanism of renal damage is lacking. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) regulates gene expression implicated in free radical scavenging and cytoprotection including the antioxidant glutathione (GSH) pathway. The aim of this study was to assess whether DEHP affects the Nrf2 pathway and the GSH concentration. Mice were divided into four groups: a control group and three groups treated with DEHP at different concentrations (5, 50, and 200 mg/kg body weight) for 30 days. Our results showed that DEHP altered the normal levels of serum biochemical parameters creatinine (CREA), urea, and lactate dehydrogenase (LDH). This phthalate caused oxidative damage through the induction of lipid peroxidation and protein oxidation as marked by increase of protein carbonyl (PC) and loss of protein-bound sulfhydryls (PSH). Simultaneously, DEHP treatment decreased the protein level of Nrf-2, HO-1, and GCLC (responsible of GSH synthesis) and decreased the GSH level. Inhibition of the Nrf2 pathway is related to the activation of the mitochondrial pathway of apoptosis. This apoptotic process is evidenced by an upregulation of p53 and Bax protein levels in addition to a downregulation of Bcl-2. Collectively, our data demonstrated that depletion of Nrf2 and GSH was associated with the elevation of oxidative stress and the activation of intrinsic apoptosis in mouse kidney treated with DEHP.

Triflumuron induces cytotoxic effects on hepatic and renal human cell lines.

Insect growth regulator insecticides are a new class of pesticides, commonly used around the world to control insect damages. Among those compounds, we focused our interest on triflumuron (TFM), which is less toxic than other conventional insecticides. However, not much is known about its toxic effects on mammalian systems. Therefore, our study aimed toward evaluating the cytotoxic and genotoxic effects of TFM using two different cell lines, the human renal embryonic cells (HEK 293) and hepatocytes (Hep G2). We showed, according to the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, that TFM reduced significantly the cell viability and increased the reactive oxygen species generation, malondialdehyde levels, and mitochondrial membrane potential in both cell lines. The antioxidant system was disturbed as assessed by the increased activities in both catalase and superoxide dismutase. We demonstrated also, that TFM is an inductor of DNA damages quantified by the comet assay. Moreover, we showed an overexpression of proapoptotic Bax and a decrease in antiapoptotic Bcl-2 expression. As a conclusion, we demonstrate that the liver presents the major target organ to TFM, in which the cytotoxicity and the genotoxic effects were significantly higher in hepatic cells than in renal cells and by consequence its uses must be controlled.

Triflumuron induces genotoxicity in both mice bone marrow cells and human Colon cancer cell line.

Triflumuron (TFM) is an insect growth regulator (IGR), an insecticide commonly used over the world. It is known for its several toxic manifestations, such as reprotoxicity, immunotoxicity and hematotoxicity, which could affect public health. However, studies that reveal its toxic effects on mammalians are limited. To reach this purpose, our study aimed to elucidate the eventual genotoxic effects of TFM in mice bone marrow cells and in HCT 116 cells after a short term exposition. TFM was administered intraperitoneally to Balb/C male mice at doses of 250, 350 and 500 mg/kg bw for 24 h. Genotoxicity was monitored in bone marrow cells using the comet test, the micronucleus test and the chromosome aberration assay. Our results showed that TFM induced DNA damages in a dose-dependent manner. This genotoxicity was confirmed also in vitro on human intestinal cells HCT 116 using the comet test. It was then asked whether this genotoxicity induced by TFM could be due to an oxidative stress. Thus, we found that TFM significantly decreased HCT 116 cell viability. In addition, it induced the generation of reactive oxygen species (ROS) followed by lipid peroxidation as revealed by the increase in the malondialdehyde (MDA) levels. Similarly, the activation of the antioxidant enzymes (catalase and superoxide dismutase) was also observed. Our results indicated that, in our experimental conditions, TFM had a genotoxic effect on bone morrow cells and in HCT 116 cells. Moreover, we demonstrated that this genotoxicity passes through an oxidative stress.

Protective effect assessment of Moringa oleifera against cadmium-induced toxicity in HCT116 and HEK293 cell lines.

The cadmium (Cd) is considered one of the widespread toxic metals in the aquatic and terrestrial environments, which is due to its long half-life, non-degradable characteristic, and toxicity. Aqueous extract of freeze-dried Moringa oleifera (Moringaceae family) leaves was examined for protective effect and antioxidant power against Cd toxicity. The results revealed that Moringa aqueous extract (MAE) has contents of total polyphenols and flavonoids about 30.14 mg GAE/g and 18.35 mg QE/g respectively. Furthermore, phenolic compounds in leaves of Moringa were studied using a high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS). Results showed that the largest number of phenolic compounds determined in leaves of Moringa belongs to flavonoids. Moreover, biological properties were determined by radical scavenging capacity (DPPH) and ferric-reducing power (FRAP). Cytoprotective effect and antioxidant power of Moringa extract were assessed using the mitochondrial activity testing method (MTT test), malondialdehyde (MDA), and reactive oxygen species (ROS) production. Results indicate that Moringa aqueous extract have a significant (i) proliferative, (ii) antioxidant, and (iii) cytoprotective effect on HCT116 and HEK293 cells against metal toxicity.

Protective effects of fennel essential oil against oxidative stress and genotoxicity induced by the insecticide triflumuron in human colon carcinoma cells.

The increased use of pesticides is the origin of multiple damages to the environment and to humans; thus, the search for new strategies to reduce or even protect the toxic effects caused by these synthetic products became a necessity. In this context, our study attempted to evaluate the protective effects of fennel essential oil (FEO), the main essential oil extracted from Faeniculum vulgare Mill., a plant with aromatic, flavorful, and medicinal uses, against toxicity induced by an insecticide-triflumuron (TFM)-in human carcinoma cells (HCT116). Our methodological approach consists of the cytotoxicity assay starting with the cell viability test, the ROS generation, the malondialdehyde (MDA) production, the DNA fragmentation, and the measurement of some antioxidant enzymes activities such as catalase (CAT) and superoxide dismutase (SOD). Also, we measured the mitochondrial transmembrane potential. The outcome of the current study showed clearly that after 2 h of HCT 116 cell pretreatment with FEO, there were increase in cell viability, reduction in ROS generation, and modulation in CAT and SOD activities induced by TFM. In the same manner, significant decreases in MDA levels were found. Mainly, the results indicated a perceptible decrease in DNA damages and a significant reduction in the mitochondrial membrane potential loss. Our work demonstrates that FEO can be an important protector against toxic effects induced by TFM in HCT 116 cells.

Di(2-ethylhexyl) phthalate inhibits glutathione regeneration and dehydrogenases of the pentose phosphate pathway on human colon carcinoma cells.

Phthalates, particularly di(2-ethylhexyl) phthalate (DEHP), are compounds widely used as plasticizers and have become serious global contaminants. Because of the bioaccumulation of such substances, the food chain is at risk. The food contamination by some phthalates has been linked to different side effects in experimental animals. That is why we have chosen the intestinal system's cells which represent the primary targets of these compounds to test their toxic effects. Human colon carcinoma cells (HCT 116) were chosen to elucidate whether DEHP triggers oxidative stress and apoptosis. Our results indicated that DEHP is cytotoxic; it induces the overexpression of Hsp70 protein and causes oxidative damage through the generation of free radicals leading to lipid peroxidation induction and the increase of superoxide dismutase (SOD) and catalase (CAT) activities. In addition, cell treatment with DEHP resulted in a glutathione (GSH) content decrease and a decrease in the glutathione reductase (GR) activity. As new evidence provided in this study, we demonstrated that the DEHP affected the two enzymes' activities of the oxidative phase of the pentose phosphate pathway: Glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD). This leads to a decrease in the level of NADPH used by the GR to maintain the regeneration of the reduced GSH. We also demonstrated that such effects can be responsible for DEHP-induced apoptosis.

Partial characterization of the edible Spinacia oleracea polysaccharides: Cytoprotective and antioxidant potentials against Cd induced toxicity in HCT116 and HEK293 cells.

Spinacia is an interesting medicinal halophyte plant that is employed as a food and therapeutic agent in traditional medicine. In this work, water-soluble polysaccharides from Spinacia oleracea were extracted and preliminary characterization was established via FT-IR, UV-vis, 1H NMR and SEC/MALS DRI technics. The extracted polysaccharide, with an average molecular mass of 408 kDa, was composed of arabinose, galactose, mannose, glucose, rhamnose and xylose in the molar percentage of 49.3%, 28.1%, 4.9%, 7.8%, 8.2% and 1.7%, respectively. The polysaccharide showed significant antioxidant activity. Moreover, Spinacia polysaccharide, significantly prevented oxidation-induced Cd damage and exhibited a protective effect against Cd cytotoxicity on HEK293 and HCT116 cells, with an important cell viability decrease, an important reduction of MDA production and ROS levels. The outcomes obtained suggest that the Spinacia polysaccharides may be used as an accessible source of natural antioxidants and as potential phytochemicals against kidney and colon cancer.

Protective effects of kefir against deltamethrin-induced hepatotoxicity in rats.

Deltamethrine (DLM) is a synthetic pyrethroid with broad spectrum activities against acaricides and insects. Widely used for agricultural and veterinary purposes, its human and animal exposure occurs by ingestion of contaminated water and food and leads to serious health problems. Kefir is fermented milk with numerous health favors counting restorative properties of bacterial flora, immune system stimulation, cholesterol reduction, as well as anti-mutagenic and anti-tumor properties. The present study was undertaken to examine the hepatoprotective and antioxidant potential of kefir against DLM toxicity in male Wistar albino rats. DLM-treated animals revealed a significant increase in serum biochemical parameters as well as hepatic protein and lipid oxidations but caused an inhibition in antioxidant enzymes. Additionally, we have observed an increase in hepatocyte DNA damages. This toxic effect was confirmed by histological study. Kefir administration normalized the elevated serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (T bilirubin), and cholesterol. It also reduced DLM-induced protein carbonyl (PC) and malondialdehyde (MDA) formations. Furthermore, Kefir treatment restored catalase (CAT) and superoxide dismutase (SOD) activities. The co-treatment as well as the pre-treatment by kefir showed an improvement of oxidative status as well as suppressed inflammation and DNA damages. However, the pre-treatment seems to be the most efficient. Therefore, it could be concluded that kefir is a natural product able to protect against the hepatotoxic effects of DLM by its free radical-scavenging and potent antioxidant activity.

Protective effects of kefir against zearalenone toxicity mediated by oxidative stress in cultured HCT-116 cells.

Kefir is a fermented milk with numerous health favors counting restorative properties of bacterial flora, reduction of the symptoms of lactose intolerance, immune system stimulation, cholesterol reduction, as well as anti-mutagenic and anti-tumor properties. Zearalenone (ZEN) is a mycotoxin produced by some Fusarium species. ZEN often occurs as a contaminant in cereal grains and animal feeds. Human exposure occurs by ingestion of mycotoxin-contaminated products and can cause serious health problems. This study aimed to assess the preventive effect of kefir against ZEN toxicity in cultured HCT-116 colorectal carcinoma cells; by the evaluation of cell viability, oxidative stress status and the initiation of apoptotic cell death pathway. Our results demonstrated that ZEN inhibits cell proliferation which was accompanied by an increase in the generation of free radicals as measured by fluorescent 2,7-dichlorofluorescein (DCF) and Malondialdehyde (MDA). As an adaptive response to this redox status, we showed an induction of heat shock protein expression (Hsp 70) and an activation of antioxidant enzymes; catalase and Superoxide Dismutase (SOD). Moreover, a loss of mitochondrial membrane potential (Δѱm) was observed. The co-treatment as well as the pre-treatment by kefir showed a reduction of ZEN induced damages for all tested markers. However, the pre-treatment seems to be the most efficient, it prevented almost all ZEN hazards. Consequently, oxidative damage appears to be a key determinant of ZEN induced toxicity in cultured HCT-116 cells. In conclusion, we showed that kefir may better exert its virtue on preventive mode rather than on curative one. By this way, kefir as a beverage with highly antioxidant properties could be relevant particularly with the emergent demand for natural products which may counteract the detrimental effects of oxidative stress and therefore prevent multiple human diseases.