The effects of endoplasmic reticulum stress inducer thapsigargin on the toxicity of ZnO or TiO2 nanoparticles to human endothelial cells

It was recently shown that ZnO nanoparticles (NPs) could induce endoplasmic reticulum (ER) stress in human umbilical vein endothelial cells (HUVECs). If ER stress is associated the toxicity of ZnO NPs, the presence of ER stress inducer thapsigargin (TG) should alter the response of HUVECs to ZnO NP exposure. In this study, we addressed this issue by assessing cytotoxicity, oxidative stress and inflammatory responses in ZnO NP exposed HUVECs with or without the presence of TG. Moreover, TiO₂ NPs were used to compare the effects. Exposure to 32?μg/mL ZnO NPs (p?2 NPs (p?>?0.05), significantly induced cytotoxicity as assessed by WST-1 and neutral red uptake assay, as well as intracellular ROS. ZnO NPs dose-dependently increased the accumulation of intracellular Zn ions, and ZnSO₄ induced similar cytotoxic effects as ZnO NPs, which indicated a role of Zn ions. The release of inflammatory proteins tumor necrosis factor α (TNFα) and interleukin-6 (IL-6) or the adhesion of THP-1 monocytes to HUVECs was not significantly affected by ZnO or TiO₂ NP exposure (p?>?0.05). The presence of 250?nM TG significantly induced cytotoxicity, release of IL-6 and THP-1 monocyte adhesion (p?p?>?0.05). ANOVA analysis indicated no interaction between exposure to ZnO NPs and the presence of TG on almost all the endpoints (p?>?0.05) except neutral red uptake assay (p?相似文献   

依达拉奉保护H9c2心肌细胞对抗异丙肾上腺素诱导的氧化应激及内质网应激反应

目的探讨依达拉奉(EDA)能否保护H9c2心肌细胞对抗异丙肾上腺素(ISO)诱导的氧化应激和内质网应激(ERS)。方法用ISO处理H9c2心肌细胞,建立β1肾上腺素受体持续兴奋诱导心肌细胞毒性的体外模型。EDA在ISO处理心肌细胞前1 h加入培养基中作为预处理。CCK-8比色法检测细胞存活率;双氯荧光素(DCFH-DA)染色/荧光显微镜照相检测细胞内活性氧(ROS)的含量;罗丹明123(Rh123)染色/荧光显微镜照相检测线粒体膜电位(MMP);Western blot法检测葡萄糖调节蛋白78(GRP78)的表达。结果 ISO在20～100μmol.L-1浓度范围内处理H9c2心肌细胞48 h,呈剂量依赖性地降低细胞存活率;80μmol.L-1ISO处理H9c2心肌细胞可使细胞内ROS含量明显增多及MMP明显降低;80μmol.L-1 ISO处理H9c2心肌细胞0～24 h,可时间依赖性地上调内质网应激蛋白GRP78的表达,其中12 h达到高峰。分别用10、20和40μmol.L-1 EDA预处理1 h可以减弱80μmol.L-1 ISO处理H9c2心肌细胞48h引起的细胞存活率降低,500、1 000和2 000μmol.L-1氧自由基清除剂NAC分别预处理1 h也可减轻ISO诱导的心肌细胞毒性反应;40μmol.L-1的EDA预处理1 h可明显减轻ISO诱导的胞内ROS堆积及MMP降低,并明显抑制ISO引起的GRP78的表达上调。结论 EDA可保护H9c2心肌细胞对抗ISO诱导的损伤作用,其机制可能与抗氧化及抑制内质网应激反应有关。     

Andrographolide-induced apoptosis in human renal tubular epithelial cells: Roles of endoplasmic reticulum stress and inflammatory response

Andrographolide sodium bisulfate as a kind of soluble derivative of andrographolide (AD), is obviously known to be nephrotoxicity, but AD has not been reported clearly. Our study aimed to investigate the induction of apoptosis in human renal tubular epithelial (HK-2) cells by AD and its possible mechanism. Our results demonstrated that AD (0–250 μmol/L) inhibited Hk-2 cells proliferation in a dose- and time-dependent manner and induced apoptosis, accompanied by decreased of superoxide dismutase (SOD) activity and increased of malondialdehvde (MDA) content. Simultaneously, AD regulated the expression of endoplasmic reticulum (ER) molecular chaperone glucose-regulated protein 78 (GRP78/Bip) protein, elevated the expressions of C/EBP homologous protein (CHOP) and Caspase-4, indicating activation of ER stress signaling, and induced the alterative expression of kidney injury molecule-1 (KIM-1), tumor necrosis factor-α (TNF-α) and Interleukin-6 (IL-6) proteins. It provided evidence that ER stress and inflammation would be significant mechanisms responsible for AD-induced apoptosis in addition to oxidative stress.     

Long-term exposure of A549 cells to titanium dioxide nanoparticles induces DNA damage and sensitizes cells towards genotoxic agents

Titanium dioxide nanoparticles (TiO₂-NPs) are one of the most produced NPs in the world. Their toxicity has been studied for a decade using acute exposure scenarios, i.e. high exposure concentrations and short exposure times. In the present study, we evaluated their genotoxic impact using long-term and low concentration exposure conditions. A549 alveolar epithelial cells were continuously exposed to 1–50?μg/mL TiO₂-NPs, 86% anatase/14% rutile, 24?±?6?nm average primary diameter, for up to two months. Their cytotoxicity, oxidative potential and intracellular accumulation were evaluated using MTT assay and reactive oxygen species measurement, transmission electron microscopy observation, micro-particle-induced X-ray emission and inductively-coupled plasma mass spectroscopy. Genotoxic impact was assessed using alkaline and Fpg-modified comet assay, immunostaining of 53BP1 foci and the cytokinesis-blocked micronucleus assay. Finally, we evaluated the impact of a subsequent exposure of these cells to the alkylating agent methyl methanesulfonate. We demonstrate that long-term exposure to TiO₂-NPs does not affect cell viability but causes DNA damage, particularly oxidative damage to DNA and increased 53BP1 foci counts, correlated with increased intracellular accumulation of NPs. In addition, exposure over 2 months causes cellular responses suggestive of adaptation, characterized by decreased proliferation rate and stabilization of TiO₂-NP intracellular accumulation, as well as sensitization to MMS. Taken together, these data underline the genotoxic impact and sensitization effect of long-term exposure of lung alveolar epithelial cells to low levels of TiO₂-NPs.     

Effects of sub-acute exposure to TiO2, ZnO and Al2O3 nanoparticles on oxidative stress and histological changes in mouse liver and brain

Abstract

Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology. However the information regarding toxicity of these nanoparticles on humans and environment is still deficient. The present study investigated the toxic effects of three metal oxide nanoparticles, TiO₂, ZnO and Al₂O₃ on mouse erythrocytes, brain and liver. Male mice were administered a single oral dose of 500?mg/kg of each nanoparticles for 21 consecutive days. The results suggest that exposure to these nano metallic particles produced a significant oxidative stress in erythrocyte, liver and brain as evident from enhanced levels of Reactive Oxygen Species (ROS) and altered antioxidant enzymes activities. A significant increase in dopamine and norepinephrine levels in brain cerebral cortex and increased brain oxidative stress suggest neurotoxic potential of these nanoparticles. Transmission electron microscopic (TEM) analysis indicated the presence of these nanoparticles inside the cytoplasm and nucleus. These changes were also supported by the inhibition of CuZnSOD and MnSOD, considered as important biomarkers of oxidative stress. The toxic effects produced by these nanoparticles were more pronounced in the case of zinc oxide, followed by aluminum oxide and titanium dioxide, respectively. The present results further suggest the involvement of oxidative stress as one of the main mechanisms involved in nanoparticles induced toxic manifestations.     

An in vivo study of nanorod,nanosphere, and nanowire forms of titanium dioxide using Drosophila melanogaster: toxicity,cellular uptake,oxidative stress,and DNA damage

ABSTRACT

The biological impact of nanomaterials (NMs) is determined by several factors such as size and shape, which need to be taken into consideration in any type of analysis. While investigators often prefer to conduct in vitro studies for detection of any possible adverse effects of NMs, in vivo approaches yield more relevant data for risk assessment. For this reason, Drosophila melanogaster was selected as a suitable in vivo model to characterize the potential risks associated with exposure nanorods (NRs), nanospheres (NSs), nanowires (NWs) forms of titanium dioxide (TiO₂), and their microparticulated (or bulk) form, as TiO₂. Third instar larvae (72 hr old larvae) were fed with TiO₂ (NRs, NSs, or NWs) and TiO₂ at concentrations ranging from 0.01 to 10 mM. Viability (toxicity), internalization (cellular uptake), intracellular reactive oxygen species (ROS) production, and genotoxicity (Comet assay) were the end-points evaluated in hemocyte D. melanogaster larvae. Significant intracellular oxidative stress and genotoxicity were noted at the highest exposure concentration (10 mM) of TiO₂ (NRs, NSs, or NWs), as determined by the Comet assay and ROS analysis, respectively. A concentration–effect relationship was observed in hemocytes exposed to the NMs. Data demonstrated that selected forms of TiO₂.-induced genotoxicity in D. melanogaster larvae hemocytes indicating this organism is susceptible for use as a model to examine in vivo NMs-mediated effects.     

Emodin induces human T cell apoptosis in vitro by ROS-mediated endoplasmic reticulum stress and mitochondrial dysfunction

Aim:

To elucidate the molecular mechanisms underlying the immunosuppressive effects of emodin isolated from Rheum palmatum L.

Methods:

Human T cells were isolated from the peripheral venous blood of 10 healthy adult donors. Cell viability was analyzed with MTT assay. AO/EB and Annexin V/PI staining and DNA damage assay were used to detect cell apoptosis. Fluorescence staining was used to detect the levels of ROS, the mitochondrial membrane potential and intracellular Ca²⁺. Colorimetry was used to detect the levels of MDA and total SOD and GSH/GSSG ratio. The expression and activity of caspase-3, -4, and -9 were detected with Western blotting and a fluorometric assay. Western blotting was also used to detect the expression of Bcl-2, Bax, cytochrome C, and endoplasmic reticulum (ER) markers.

Results:

Emodin (1, 10, and 100 μmol/L) inhibited the growth of human T cells and induced apoptosis in dose- and time dependent manners. Emodin triggered ER stress and significantly elevated intracellular free Ca²⁺ in human T cells. It also disrupted mitochondrial membrane potential, and increased cytosolic level of cytochrome C, and the levels of activated cleavage fragments of caspase-3, -4, and -9 in human T cells. Furthermore, emodin significantly increased the levels of ROS and MDA, inhibited both SOD level and GSH/GSSG ratio in human T cells, whereas co-incubation with the ROS scavenger N-acetylcysteine (NAC, 20 μmol/L) almost completely blocked emodin-induced ER stress and mitochondrial dysfunction in human T cells, and decreased the caspase cascade-mediated apoptosis.

Conclusion:

Emodin exerts immunosuppressive actions at least partly by inducing apoptosis of human T cells, which is triggered by ROS-mediated ER stress and mitochondrial dysfunction.     

Oxidative stress studies of six TiO2 and two CeO2 nanomaterials: Immuno-spin trapping results with DNA

Abstract

Six TiO₂ and two CeO₂ nanomaterials with dry sizes ranging from 6–410 nm were tested for their ability to cause DNA centered free radicals in vitro in the concentration range of 10–3,000 ug/ml. All eight of the nanomaterials significantly increased the adduction of the spin trap agent 5,5-dimethyl-1-pyroline N-oxide (DMPO) to DNA as measured by the experimental technique of immuno-spin trapping. The eight nanomaterials differed considerably in their potency, slope, and active concentration. The largest increase in DNA nitrone adducts was caused by a TiO₂ nanomaterial (25 nm, anatase) from Alfa Aesar. Some nanomaterials that increased the amount of DNA nitrone adducts at the lowest exposure concentrations (100 ug/ml) were Degussa TiO₂ (31 nm), Alfa Aesar TiO₂ (25 nm, anatase) and Nanoamor CeO₂ (8 nm, cerianite). At exposure concentrations of 10 or 30 ug/ml, no nanomaterials showed significant in vitro formation of DNA nitrone adducts.     

Oral intake of added titanium dioxide and its nanofraction from food products,food supplements and toothpaste by the Dutch population

Titanium dioxide (TiO₂) is commonly applied to enhance the white colour and brightness of food products. TiO₂ is also used as white pigment in other products such as toothpaste. A small fraction of the pigment is known to be present as nanoparticles (NPs). Recent studies with TiO₂ NPs indicate that these particles can have toxic effects. In this paper, we aimed to estimate the oral intake of TiO₂ and its NPs from food, food supplements and toothpaste in the Dutch population aged 2 to over 70 years by combining data on food consumption and supplement intake with concentrations of Ti and TiO₂ NPs in food products and supplements. For children aged 2–6 years, additional intake via ingestion of toothpaste was estimated. The mean long-term intake to TiO₂ ranges from 0.06?mg/kg bw/day in elderly (70+), 0.17?mg/kg bw/day for 7–69-year-old people, to 0.67?mg/kg bw/day in children (2–6 year old). The estimated mean intake of TiO₂ NPs ranges from 0.19?μg/kg bw/day in elderly, 0.55?μg/kg bw/day for 7–69-year-old people, to 2.16?μg/kg bw/day in young children. Ninety-fifth percentile (P95) values are 0.74, 1.61 and 4.16?μg/kg bw/day, respectively. The products contributing most to the TiO₂ intake are toothpaste (in young children only), candy, coffee creamer, fine bakery wares and sauces. In a separate publication, the results are used to evaluate whether the presence of TiO₂ NPs in these products can pose a human health risk.     

Molecular approaches to the treatment, prophylaxis, and diagnosis of Alzheimer's disease: endoplasmic reticulum stress and immunological stress in pathogenesis of Alzheimer's disease

Alzheimer's disease (AD) is an age-related neurodegenerative disorder, accompanied by neuronal loss and the formation of senile plaques in the brain. Glial cells, such as microglia, have been shown to be activated and induce chronic inflammatory responses in AD brain. The endoplasmic reticulum (ER) functions to facilitate protein folding. However, ER stress occurs when cells are exposed to stress. Mounting evidence suggests that ER stress is involved in the pathology of AD. Meanwhile, recent findings suggested crosstalk between ER stress and immune function. However, the mechanisms linking the progression of AD with ER and immunological stress are still not clear. In the present paper, we review and discuss recent results regarding the mechanism of AD pathogenesis, focusing on ER stress and immunological stress.     

TiO2 nanoparticles induce oxidative DNA damage and apoptosis in human liver cells

Abstract

Titanium dioxide nanoparticles (TiO₂ NPs), widely used in consumer products, paints, pharmaceutical preparations and so on, have been shown to induce cytotoxicity, genotoxicity and carcinogenic responses in vitro and in vivo. The present study revealed that TiO₂ NPs induce significant (p < 0.05) oxidative DNA damage by the Fpg-Comet assay even at 1 µg/ml concentration. A corresponding increase in the micronucleus frequency was also observed. This could be attributed to the reduced glutathione levels with concomitant increase in lipid peroxidation and reactive oxygen species generation. Furthermore, immunoblot analysis revealed an increased expression of p53, BAX, Cyto-c, Apaf-1, caspase-9 and caspase-3 and decreased the level of Bcl-2 thereby indicating that apoptosis induced by TiO₂ NPs occurs via the caspase-dependent pathway. This study systematically shows that TiO₂ NPs induce DNA damage and cause apoptosis in HepG2 cells even at very low concentrations. Hence the use of such nanoparticles should be carefully monitored.     

Involvement of endoplasmic reticulum stress in angiotensin II-induced NLRP3 inflammasome activation in human renal proximal tubular cells in vitro

Aim:

NLRP3 inflammasome plays an important role in renal injury and may be a therapeutic target in the treatment of patients with progressive chronic kidney disease. In this study we investigated whether angiotensin II (Ang II)-induced NLRP3 inflammasome activation was linked to endoplasmic reticulum stress (ERS) in human renal proximal tubular cells in vitro.

Methods:

Human kidney proximal epithelial cells (HK-2) were pretreated with telmisartan or 4-PBA, and then treated with Ang II. The expression levels of mRNAs and proteins related to NLRP3 inflammasomes and ERS was examined by real-time PCR, Western blot and immunofluorescence.

Results:

Treatment with Ang II (10, 100, and 1000 nmol/L) increased the expression of the inflammasome markers NLRP3 and ASC, as well as caspase-1, IL-1β, and IL-18 in dose- and time-dependent manners with peak levels detected at 100 nmol/L and 12 h. Ang II-induced increases in the expression of NLRP3, ASC, caspase-1, IL-1β, and IL-18 were significantly reduced by pretreatment with telmisartan (1 μmol/L). Immunofluorescence studies showed that Ang II increased the expression of NLRP3 and ASC, which was inhibited by telmisartan. Furthermore, Ang II treatment increased the expression of ERS markers GRP78 and p-eIF2α in dose- and time-dependent manners, which was significantly reduced by telmisartan. Moreover, Ang II-induced increases in the expression of NLRP3, ASC, caspase-1, IL-1β, and IL-18 were significantly inhibited by pretreatment with the ERS inhibitor 4-PBA (5 mmol/L).

Conclusion:

Ang II treatment induces NLRP3 inflammasome activation in HK-2 cells in vitro and ER stress is involved in this process, which may represent a new mechanism for the renal rennin-angiotensin system to induce tubulointerstitial inflammation.     

Cytotoxicity,oxidative stress,and inflammation in human Hep G2 liver epithelial cells following exposure to gold nanorods

The gold nanorods (GNRs) are great potentials in imaging, therapy, biosensing, and many other commercial applications. However, GNRs interactions with human cells and potential health risks remain not well known. The present investigation aimed to evaluate the in vitro toxicity of 10 and 25?nm GNRs (10–50?μg/mL) following exposure for 48?h in human Hep G2 liver epithelial cells using 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), lactate dehydrogenase (LDH) leakage, glutathione (GSH) estimation, lipid peroxidation (TBARS), caspase-3 levels, and interleukin-8 (IL-8) release assays. Exposure of GNRs to cells results in decrease in cell viability and causes cell membrane damage through LDH leakage results in cytotoxicity. The IC₅₀ (concentration required to inhibit 50% of cells) values of 10?nm GNRs, 25?nm GNRs, and quartz (toxic control)-treated cells were found to be 19.9, 26.8, and 36.35?μg/mL, suggesting the higher cytotoxicity of GNRs. The GNRs exposure to liver cells found in depleted GSH levels, increased lipid peroxidation, and increased caspase-3 levels leads to induction of oxidative stress. In addition, enhanced levels of IL-8 were found, a sign of inflammation. The 10?nm GNRs have shown significant toxicity against all biochemical assays when compare to 25?nm GNRs and quartz-treated cells. Finally, the data indicate that the concentration size-dependent in vitro toxicity of GNRs toward liver Hep G2 cells. The toxicity of GNRs may be due to cell membrane damage, induction of oxidative stress, and inflammatory mediator release. Further investigations are necessitated to elucidate the in vivo toxicity of GNRs.     

Acute and chronic toxicity of nano-scale TiO2 particles to freshwater fish,cladocerans, and green algae,and effects of organic and inorganic substrate on TiO2 toxicity

This research evaluated the toxicity of TiO₂ nanoparticles to freshwater aquatic organisms and the effects of organic and inorganic material on TiO₂ toxicity. The fathead minnow was much less acutely sensitive to TiO₂ (LC50 500 mg/l and higher) than Ceriodaphnia dubia and Daphnia pulex (mean LC50 values 7.6 and 9.2 mg/l, respectively). Total organic carbon levels of 1.5 mg/l decreased TiO₂ acute toxicity to C. dubia (LC50 > 100 mg/l), but kaolinite clay decreased TiO₂ toxicity to a lesser extent. In chronic toxicity tests, the green algae Pseudokirchneriella subcapitata was more sensitive to TiO₂ (IC25 1–2 mg/l) than C. dubia (IC25 9.4–26.4 mg/l) and the fathead minnow (IC25 values over 340 mg/l). Study results indicate that the specific organisms exposed and the effects of water quality parameters on TiO₂ toxicity should be considered in hazard evaluations of this nanoparticle.     

TNF/TNFR1 pathway and endoplasmic reticulum stress are involved in ofloxacin-induced apoptosis of juvenile canine chondrocytes

Background and purpose

Quinolones cause obvious cartilaginous lesions in juvenile animals by chondrocyte apoptosis, which results in the restriction of their use in pediatric and adolescent patients. Studies showed that chondrocytes can be induced to produce TNFα, and the cisternae of the endoplasmic reticulum in quinolone-treated chondrocytes become dilated. We investigated whether TNF/TNFR₁ pathway and endoplasmic reticulum stress (ERs) are involved in ofloxacin (a typical quinolone)-induced apoptosis of juvenile canine chondrocytes.

Experimental approach

Canine juvenile chondrocytes were treated with ofloxacin. Cell survival and apoptosis rates were determined with MTT method and flow cytometry, respectively. The gene expression levels of the related signaling molecules (TNFα, TNFR₁, TRADD, FADD and caspase-8) in death receptor pathways and main apoptosis-related molecules (calpain, caspase-12, GADD153 and GRP78) in ERs were measured by qRT-PCR. The gene expression of TNFR₁ was suppressed with its siRNA. The protein levels of TNFα, TNFR₁ and caspase-12 were assayed using Western blotting.

Key results

The survival rates decreased while apoptosis rates increased after the chondrocytes were treated with ofloxacin. The mRNA levels of the measured apoptosis-related molecules in death receptor pathways and ERs, and the protein levels of TNFα, TNFR₁ and caspase-12 increased after the chondrocytes were exposed to ofloxacin. The downregulated mRNA expressions of TNFR₁, Caspase-8 and TRADD, and the decreased apoptosis rates of the ofloxacin-treated chondrocytes occurred after TNFR₁–siRNA interference.

Conclusions and implications

Ofloxacin-induced chondrocyte apoptosis in a time- and concentration-dependent fashion. TNF/TNFR₁ pathway and ERs are involved in ofloxacin-induced apoptosis of juvenile canine chondrocytes in the early stage.     

Involvement of both endoplasmic reticulum and mitochondria in photokilling of nasopharyngeal carcinoma cells by the photosensitizer Zn-BC-AM

Photodynamic therapy (PDT) is recently developed as an effective treatment for malignant disease. In PDT, the photosensitizer eradicates tumour by induction of apoptosis. In this study, we investigated the mechanistic actions of a recently developed second generation photosensitizer, Zn-BC-AM, on nasopharyngeal carcinoma (NPC) cells. Zn-BC-AM was found to localize in the mitochondria, endoplasmic reticulum (ER), and golgi body. Photoactivation of Zn-BC-AM loaded NPC cells resulted in a rapid collapse of mitochondrial membrane potential (Deltapsim) (15 min), followed by the release of cytochrome c (1 h), and activation of caspases-9 and -3 (4 h). Expression of ER chaperones Bip/Grp78 and Grp94, and ER resident lectin-like chaperone calnexin (CNX) was also enhanced in PDT-stressed NPC cells. Caspase-12, an important caspase involved in ER stress-induced apoptosis, was also activated. Inhibition of Ca2+ uptake into mitochondria by ruthenium red (RR) or loading the cells with EGTA-AM, an agent that buffers intracellular Ca2+ released from ER, resulted in a significant reduction of Zn-BC-AM PDT-induced cell death. These observations suggest that both ER and mitochondria are the subcellular targets of Zn-BC-AM. Effective activation of ER- and mitochondria-mediated apoptotic pathways is responsible for Zn-BC-AM PDT-induced NPC cell death.     

Oral,short-term exposure to titanium dioxide nanoparticles in Sprague-Dawley rat: focus on reproductive and endocrine systems and spleen

The study explored possible reproductive and endocrine effects of short-term (5 days) oral exposure to anatase TiO₂ nanoparticles (0, 1, 2 mg/kg body weight per day) in rat. Nanoparticles were characterised by scanning electron microscopy (SEM) and transmission electron microscopy, and their presence in spleen, a target organ for bioaccumulation, was investigated by single-particle inductively coupled plasma mass spectrometry and SEM/energy-dispersive X-ray. Analyses included serum hormone levels (testosterone, 17-β-estradiol and triiodothyronine) and histopathology of thyroid, adrenals, ovary, uterus, testis and spleen. Increased total Ti tissue levels were found in spleen and ovaries. Sex-related histological alterations were observed at both dose levels in thyroid, adrenal medulla, adrenal cortex (females) and ovarian granulosa, without general toxicity. Altered thyroid function was indicated by reduced T3 (males). Testosterone levels increased in high-dose males and decreased in females. In the spleen of treated animals TiO₂ aggregates and increased white pulp (high-dose females) were detected, even though Ti tissue levels remained low reflecting the low doses and the short exposure time. Our findings prompt to comprehensively assess endocrine and reproductive effects in the safety evaluation of nanomaterials.     

Potential in vitro antioxidant and protective effects of Soymida febrifuga on ethanol induced oxidative damage in HepG2 cells

There is increasing evidence that oxidative stress is implicated in pathogenesis of various diseases, including alcoholic liver injury. In the present study, we investigated the comparative protective effects of leaf, bark, root and root bark extracts of Soymida febrifuga (Roxb.) A. Juss. (Meliaceae) against ethanol induced oxidative damage in HepG2 cells. Comparatively, methanolic and aqueous extracts of bark and leaf significantly attenuated the cytotoxicity of the ethanol, as determined by cytotoxicity, lipid peroxidation, lactate dehydrogenase, alanine aminotransferases and asparatate aminotransferases, than the root and root bark extracts. Ethanol induces liver toxicity through free radical generation so initially in vitro antioxidant activity of the extracts was evaluated. Methanolic and aqueous extracts of bark and leaf have shown higher total phenolic content, reducing power, metal chelating, superoxide, hydroxyl radical, hydrogen peroxide and nitric oxide (murine macrophage cells) scavenging activity than the root and root bark extracts.     

DNA damage in male gonad cells of Green mussel (Perna viridis) upon exposure to tobacco products

DNA damage (determined by the Comet Assay) and the occurrence of deformed nuclei were measured as endpoints of genotoxicity in male gonad cells of the marine mussel (Perna viridis). Upon exposure of the organism to varying concentrations of extracts of smoked and non-smoked cigar tobacco over a period of 16 days, DNA damage was found to be highest in marine mussels exposed to extracts of smoked cigar tobacco. Conversely, more deformed nuclei were detected in marine mussels exposed to extracts of non-smoked cigar tobacco. The level of DNA damage and the number of deformed nuclei reach a maximum at day 12 of exposure to both extracts but decrease thereafter. This phenomenon is attributed to the organism’s capacity to maintain the integrity of its genetic material upon exposure to potential genotoxicants present in the tobacco extracts. A dose response in DNA damage and deformed nuclei was also detected in isolated gonad cells upon in vitro exposure to hydrogen peroxide a known DNA strand breaking agent. The results of this study indicate that the DNA in male gonad cells of the marine mussel is damaged upon exposure to genotoxicants, and suggests the suitability of the organism for future investigations into the effect of such agents on its reproductive capacities.Special Issue on Biomarkers of Marine Pollution and Bioremediation     

Contribution of oxidative stress in acute intestinal mucositis induced by 5 fluorouracil (5-FU) and its pro-drug capecitabine in rats

This study was designed to examine the contribution of oxidative stress in gastrointestinal disorders after an intraperitoneal administration of 5 fluorouracil (5-FU; 100?mg/kg of body weight (b.w.)) and capecitabine oral administration (500?mg/kg b.w.). The animals were divided into three groups: Group A (NaCl,10?ml/kg of b.w.) considered as control group, group B was intoxicated by 5-FU and group C was the group of animals treated with capecitabine (CAP). To evaluate the secretory and enteropooling effects, we used magnesium sulfate (MgSO₄), 1?ml/100?g of b.w. as a hypersecretion agent . The mucosal gastro-intestinal specimens were scraped and examined for biological markers of oxidative stress and intracellular mediators. These anticancer drugs caused many intestinal damages manifested by an elevation of fluid accumulation and imbalance in electrolytes secretion. The intestinal tissues from treated rats not only showed a significant increase in malondialdehyde (MDA), protein carbonylation and hydrogen peroxide (H₂O₂) production. but also showed a significant depletion of enzymatic and non-enzymatic antioxidant, such as, glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT) and sulfhydryl groups (-SH). These effects were related with histopathological damage and a perturbation of intracellular mediators. As expected, these disturbances were observed in the group of rats poisoned by the MgSO₄. Data suggest the contribution of oxidative stress in chemotherapy-induced many disorders in intestinal tract.