Mohammed Mahboob

Toxicity Study of Cerium Oxide Nanoparticles in Human Neuroblastoma Cells

The present study consisted of cytotoxic, genotoxic, and oxidative stress responses of human neuroblastoma cell line (IMR32) following exposure to different doses of cerium oxide nanoparticles (CeO2 NPs; nanoceria) and its microparticles (MPs) for 24 hours. Cytotoxicity was evaluated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide and lactate dehydrogenase assays whereas genotoxicity was assessed using the cytokinesis-block micronucleus and comet assays. A battery of assays including lipid peroxidation, reactive oxygen species (ROS), hydrogen peroxide, reduced glutathione, nitric oxide, glutathione reductase, glutathione peroxidase, superoxide dismutase, catalase, and glutathione S-transferase were performed to test the hypothesis that ROS was responsible for the toxicity of nanoceria. The results showed that nanosized CeO2 was more toxic than cerium oxide MPs. Hence, further study on safety evaluation of CeO2 NPs on other models is recommended.

Genotoxicity in Filling Station Attendants Exposed to Petroleum Hydrocarbons

OBJECTIVESnBiomonitoring of exposure in workplaces has gained importance in evaluation of human health hazards. Since occupational exposure to petroleum hydrocarbons may have deleterious effects, genotoxicity risk among 200 fuel filling station attendants (FFSAs) and 200 matched controls was investigated.nnnMETHODSnThe probable genetic damage was determined by comet assay and micronucleus test in peripheral blood lymphocytes (PBL) of study subjects. Air and blood sample analysis was done to estimate the benzene, toluene, and xylene (BTX) concentrations using gas chromatography-mass spectrometry. The effect of exposure on antioxidant enzymes was also studied by determining the levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and rate of lipid peroxidation measured as concentration of malondialdehyde (MDA) formed.nnnRESULTSnThe results of the present study suggest that there was a statistically significant increase in mean comet tail length (25.09 versus 10.27 μm) and frequency of micronuclei in PBL (11.83 versus 5.83 per thousand; P < 0.05) of FFSAs as compared to controls. BTX concentrations were found to be significantly higher in ambient air of petrol pumps and FFSAs showed elevated levels of these compounds in their breathing zone in comparison to controls (P < 0.05). Blood BTX levels were found to be significantly enhanced in FFSAs. SOD and GPx were significantly decreased with an increased rate of CAT and MDA in FFSAs as compared to controls.nnnCONCLUSIONSnThe results of our study suggest that exposure to BTX has the potential to cause genetic changes in the exposed subjects. The data highlight the need to maintain safety measures and intervention to minimize exposure.

Oxidative stress induced by aluminum oxide nanomaterials after acute oral treatment in Wistar rats.

This study investigated the oxidative stress induced after acute oral treatment with 500, 1000 and 2000u2009mg kg−1 doses of Al2O3‐30 and −40u2009nm and bulk Al2O3 in Wistar rats. Both the nanomaterials induced significant oxidative stress in a dose‐dependent manner in comparison to the bulk. There was no significant difference between the two nanomaterials. However, the effect decreased with increase with time after treatment. The histopathological examination showed lesions only in liver with Al2O3 nanomaterials at 2000u2009mg kg−1. Copyright

Biochemical alterations induced by acute oral doses of iron oxide nanoparticles in Wistar rats

Magnetic iron oxide nanoparticles with appropriate surface chemistry have been widely used with potential new applications in biomedical industry. Therefore, the aim of this study was to assess the size-, dose-, and time-dependent effects, after acute oral exposure to iron oxide-30 NP (Fe2O3-30), on various biochemical enzyme activities of clinical significances in a female Wistar rat model. Rats were exposed to three different doses (500, 1,000, and 2,000u2009mg/kg) of Fe2O3-30 and Fe2O3-Bulk along with control. Fe2O3-30 had no effect on growth, behavior, and nutritional performance of animals. Fe2O3-30 caused significant inhibition of acetylcholinestrase in red blood cells as well as in brains of treated rats. Further, more than 50% inhibition of total, Na+-K+, Mg2+, and Ca2+-ATPases activities, as observed in brains of exposed female rats, may be the result of disturbances in cellular physiology and the iono-regulatory process. Activation of the hepatotoxicity marker enzymes, aspartate aminotransferase and alanine aminotransferase, was recorded in serum and liver, whereas inhibition was observed in kidney. Similarly, enhancement of lactate dehydrogenase activity was observed in serum and liver; however, a decrease in enzyme levels was observed in kidneys of Fe2O3-30-treated rats. On the other hand, Fe2O3-Bulk did not depict any significant changes in these biochemical parameters, and alterations were near to control. Therefore, this study suggests that exposure to nanosize particles at acute doses may cause adverse changes in animal biochemical profiles. The use of the rat model signifies the correlation with the human system.

Assessment of genotoxic effects of lead in occupationally exposed workers

The genotoxicological effects in 200 lead acid storage battery recycling and manufacturing industry workers in Hyderabad along with matched 200 controls were studied. The genetic damage was determined by comet, micronucleus (MN), and chromosomal aberration (CA) test in peripheral blood lymphocytes (PBL). The MN test was also carried out in buccal epithelial cells (BECs). Pb in ambient air, blood Pb (B-Pb) concentrations, and hematological parameters were measured. The superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione peroxidase (GPx), and malondialdehyde (MDA) formed were also studied. The results of the present study showed that there was a statistically significant (Pu2009<u20090.01) increase in mean percent tail DNA, frequency of CA, and MN in PBL as well as in BEC as compared to controls. Pb in ambient air and B-Pb concentrations were found to be significantly higher (Pu2009<u20090.01). The hematocrit, hemoglobin, and red blood cell values were significantly lowered in Pb-exposed workers in comparison to controls. SOD, GPx, and CAT levels were significantly decreased while GSH and MDA levels increased in exposed group when compared to control group. The present study suggests that environmental health standards should be enforced to control Pb contamination from battery industries to reduce human health risk.

Toxicological assessment of tungsten oxide nanoparticles in rats after acute oral exposure

Advances in and the rapid growth of the nanotechnology sector have escalated manufacture of nanoparticles (NPs), resulting in a significant increase in the probability of exposure of humans and wildlife to these materials. Many NPs have been found to exert genotoxicity. Therefore, genotoxicity studies are mandatory to assess the toxicity of NPs as a concern of succumbing to genetic diseases and cancers are universal. Tungsten oxide (WO3) NPs are being explored extensively in various fields. However, the toxicological data of WO3 NPs by oral route in mammals is limited. Hence, the goal of the current investigation was to evaluate the acute toxicity of WO3 NPs and microparticles (MPs) after single oral administration with 100, 500 and 1000xa0mg/kg body weight doses in female Wistar rats. TEM, dynamic light scattering and laser Doppler velocimetry techniques were used to characterise the particles. The genotoxicity studies were conducted using comet, micronucleus and chromosomal aberration assays. Alterations in biochemical indices and metal distribution in various organs were also evaluated. The mean size of WO3 NPs and MPs by TEM was 53.2xa0±xa01.91xa0nm and 5.17xa0±xa03.18xa0μm, respectively. The results revealed a significant increase in DNA damage and micronuclei and chromosomal aberrations after exposure to 1000xa0mg/kg dose of WO3 NPs. Significant alterations in aspartate transaminase, alanine transaminase, reduced glutathione, catalase and malondialdehyde levels in serum and liver were found only at the higher dose of WO3 NPs. Tungsten (W) biodistribution was observed in all the tissues in a dose-, time- and organ-dependent manner. In addition, the maximum concentration of W was found in the liver and the least in the brain was observed. The test substances were found to have a relatively low acute toxicity hazard. The data obtained gives preliminary information on the potential toxicity of WO3 NPs and MPs.

Interaction of monocrotophos and its novel thion analogues with microsomal cytochrome P-450: in vivo and in vitro studies in rat

The binding of monocrotophos (MCP) and its two thion analogues (coded as RPR-II and RPR-V) to rat hepatic microsomal cytochrome P-450 (HMC) were investigated in vitro by difference spectroscopy. These three organophosphorus insecticides were found to bind stoichiometrically to HMC with very high affinity (Ks 34-50 microM). RPR-V showed the highest binding affinity followed by RPR-II and MCP. Association of these compounds with HMC occurred within 2 min of addition in the cuvette and therefore, appeared to be tight binding ligands of cytochrome P-450. In vivo studies at equitoxic doses of the three compounds 24 h after oral treatment in rats revealed that they all caused reduction in MC content in liver, lung, kidney and brain, as against induction in cardiac and splenic cytochrome P-450. These in vivo results suggest organ specificity in modulating the microsomal cytochrome P-450 (MC) content of hepatic and extra-hepatic tissues by the three compounds. Apparently, their binding affinity with HMC is strongly correlated with their LD50 value and has a substantial co-relationship with the cytochrome P-450 level in the liver.

Design, synthesis and immunological evaluation of 1,2,3-triazole-tethered carbohydrate-Pam3Cys conjugates as TLR2 agonists.

Novel triazolyl Pam3Cys conjugates encompassing various carbohydrate entities have been synthesized by copper mediated azide-alkyne click chemistry protocol with a view to probe the SAR pertaining to their adjuvant activity in conjunction with OVA as antigen. The preliminary ex vivo cytokine profiling revealed optimal Th1 activation and the in vivo adjuvant studies of ribose derived hybrid (6 e) revealed a marked improvement in the OVA specific antibody IgG response and Th1 cytokine expressions. The triazolyl Pam3Cys carbohydrate conjugates were found to be the hTLR2 agonists as revealed by their SEAP activity due to NFKB activation. The described protocol is the first successful attempt of the amalgamation of carbohydrate-Pam3Cys motifs tethered to a triazole linker as a peptide free adjuvant.