Toxicology and Industrial Health

Amara, Salem ;Douki, Thierry ;Garrel, Catherine ;Favier, Alain ;Rhouma, Khémais Ben;Sakly, Mohsen ;Abdelmelek, Hafedh

doi: 10.1177/0748233710381887pmid: 20837562

The present study was undertaken to determine the effect of co-exposure to static magnetic field (SMF) and cadmium (Cd) on the antioxidant enzymes activity and DNA integrity in rat brain. Sub-chronic exposure to CdCl (CdCl2, 40 mg/L, per os) for 30 days resulted in a significant reduction in antioxidant enzyme activity such as the glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) in frontal cortex and hippocampus. Total GSH were decreased in the frontal cortex of the Cd-exposed group. Cd exposure induced an increase in malondialdehyde (MDA) concentration in the frontal cortex and hippocampus. Moreover, the same exposure increased 8-oxo-7,8-dihydro-2-desoxyguanosine (8-oxodGuo) level in rat brain. Interestingly, the combined effect of SMF (128 mT, 1 hour/day for 30 consecutive days) and CdCl (40 mg/L, per os) decreased the SOD activity and glutathione level in frontal cortex as compared with the Cd group. Moreover, the association between SMF and Cd increased MDA concentration in frontal cortex as compared with Cd-exposed rats. DNA analysis revealed that SMF exposure failed to alter 8-oxodGuo concentration in Cd-exposed rats. Our data showed that Cd exposure altered the antioxidant enzymes activity and induced oxidative DNA lesions in rat brain. The combined effect of SMF and Cd increased oxidative damage in rat brain as compared with Cd-exposed rats.

Priya, S. Laxmi;Senthilkumar, B. ;Hariharan, G. ;Selvam, A. Paneer;Purvaja, R. ;Ramesh, R.

doi: 10.1177/0748233710381892pmid: 20921056

The accumulation of six heavy metals (Cr, Cd, Cu, Zn, Pb and Ni) in sediment, water and in tissue parts of Mugil cephalus and Crassostrea madrasensis was studied in two locations of Pulicat lake, Southeast coast of India, which receives considerable quantity of effluents from industries located in North Chennai coastal region. The results reveal that the metal concentration in water is decreasing in the following order of Zn > Ni > Cu > Cr > Pb > Cd both in lake and barmouth and highest concentration was observed for Zn (32.5 μg L-1 in lake and 25.2 μg L-1 in bar mouth). Metals were highly concentrated in sediments when compared to water and biota. Metals abundance in sediments has following sequential order of Cr > Ni > Zn > Cu > Pb > Cd and the accumulation pattern in barmouth showed minor variation indicating the following pattern of Zn > Ni > Cr > Cu > Pb > Cd. The geoaccumulation index (Igeo) for Pulicat lake sediments indicate that the sediments are extremely contaminated with Cd and moderately contaminated with Cu and Ni. Bioaccumulation of heavy metals in Mugil cephalus and Crassostrea madrasensis showed marked differences in the accumulation patterns. It is observed that Zn, Cu and Pb are accumulated in elevated concentrations in various parts of the fish and oyster when compared with other metals.

Coşkun, Özlem ;Naziroğlu, Mustafa ;Çömlekçi, Selçuk ;Özkorucuklu, Suat

doi: 10.1177/0748233710381893pmid: 20823053

The aim of this study was to investigate possible effects of 50 Hz-1 mT magnetic field (MF) on action potential in isolated rat sciatic nerve. We used 16 Wistar rats in the study. They were divided into control (n = 10) and MF (n = 6) groups. The sciatic nerve of left legs in the MF group was exposed to 50 Hz-1 mT MF for 30 min by using a Helmholtz applicator and then action potentials in control and experimental groups were recorded extracellularly. Maximum amplitude and hyperpolarization time and action potential were significantly (p ≤ 0.025) lower in the MF group than in control. However, conduction time, minimum amplitude, depolarization and repolarization times of the action potential was not different between control and MF groups evaluated. In conclusion, 50-1 mT MF caused to decrease amplitude value and hyperpolarization time of action potential in the rat nerve.

Turkez, Hasan ;Geyikoglu, Fatime

doi: 10.1177/0748233710381894pmid: 20823050

Aluminum (Al) is commonly used in industrial processes and drugs and is thought to induce erythrocytes damage via activation of oxidative stress. Recently, bismuth (Bi)-containing drugs are used in the treatment of various diseases. However, uncertain effects of Bi in blood tissue may participate in the therapeutic efficacy of Bi compounds as related to metals. Hence, this study aimed to determine the roles on human blood cells of the various concentrations of aluminum sulphate (Al2 (SO4)3) and bismuth subnitrate (BSN), separate and together. With this aim, oxidative status was assessed on erythrocytes by measuring following oxidative stress markers: reduced glutathione (GSH), superoxide dismutase (SOD), glucose-6-phosphate dehydrogenase (G-6-PDH) and catalase (CAT). Two chemicals were tested for their ability to induce cytogenetic change in human lymphocytes using assays for chromosome aberrations (CAs) and sister chromatid exchanges (SCEs). Our results showed that high dose of Al2(SO4)3 (20 µg/mL) caused oxidative stress and increased CA and SCE frequencies. Whereas, BSN doses did not change CA and SCE rates. Moreover, it led to changes of antioxidant capacity at different concentrations. After concomitant treatment with Al2(SO 4)3 and BSN, the effects of BSN doses were different on enzyme activities and decreased the genotoxic damage. However, the high dose of BSN and Al2(SO4)3 was shown to enhance the frequencies of CAs and SCEs in a synergistic manner. In conclusion, BSN could be effective in the protection against the blood toxicity of Al 2(SO4)3.

Ohgami, Nobutaka ;Kondo, Takaaki ;Kato, Masashi

doi: 10.1177/0748233710382539pmid: 20858647

There have been few reports showing a correlation between hearing levels and life style in young people. In this study, we succeeded in sensitively evaluating hearing levels in 51 young male adults of 21-23 years in age by 12 k Hz extra-high-frequency auditory thresholds, which cannot be measured by usual audiometry devices for clinical use. Noise exposure, alcohol consumption and sleeping time did not affect hearing levels in young adults. Auditory thresholds of 12 kHz frequency in smokers were significantly (p < 0.05) higher than those in non-smokers, while there were no differences in 1 kHz, 4 kHz and 8 kHz frequencies of hearing levels between smokers and non-smokers. Since the Brinkman Index (BI; cigarettes/day multiplied by number of years) of smokers in this study was from 12 to 60, our results suggest that even light smoking of less than 20 cigarettes/day for 3 years can result in the development of hearing loss of 12 kHz frequency in young adults. Binary logistic regression analysis again showed a correlation between hearing loss (≥40 dB of auditory thresholds in 12 kHz frequency) and light smoking (12 ≤ BI ≤ 60). Thus, this study showed that auditory threshold at 12 kHz frequency could be a sensitive marker for hearing in young adults. More importantly, we for the first time provided epidemiological evidence that light smoking might affect hearing level at 12 kHz frequency and revealed a new risk of light smoking.

Sung, Jae Hyuck;Ji, Jun Ho;Song, Kyung Seuk;Lee, Ji Hyun;Choi, Kyung Hee;Lee, Sang Hee;Yu, Il Je

doi: 10.1177/0748233710382540pmid: 20870693

The acute inhalation toxicity of silver nanoparticles was studied in Sprague-Dawley rats. Seven-week-old rats, weighing approximately 218 g (males) and 153 g (females), were divided into four groups (five rats in each group): fresh-air control, low-dose (0.94 × 106 particle/cm3, 76 µg/m3), middle-dose (1.64 × 106 particle/ cm3, 135 µg/m 3), and high-dose (3.08 × 106 particle/cm3, 750 µg/m3). The animals were then exposed to silver nanoparticles (average diameter 18-20 nm) for 4 hours in a whole-body inhalation chamber. The experiment was conducted following Organization Economic Cooperation and Development (OECD) test guideline 403 with the application of good laboratory practice (GLP). In addition to mortality and clinical observations, the body weights, food consumption, and pulmonary function tests were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, and the organ weights measured. The lung function was also measured twice per week after the initial 4-hour exposure. No significant body weight changes or clinical changes were found during the 2-week observation period. The lung function tests also indicated no significant difference between the fresh air control and the exposed groups. Thus, LC50 silver nanoparticles are suggested for higher than 3.1 × 106 particles/cm3 (750 µg/m3).

Kanter, Mehmet

doi: 10.1177/0748233710382541pmid: 20837561

The aim of this study was designed to evaluate the possible protective effects of thymoquinone (TQ) on the spermatogenesis after testicular injury caused by chronic toluene exposure in rats. The rats were randomly allotted into one of three experimental groups: control, toluene-treated and toluene treated with TQ; each group contained 10 animals. Control group received 1 mL serum physiologic and toluene treatment was performed by inhalation of 3000 ppm toluene, in an 8-hour/day and 6-day/week order for 12 weeks. The rats in TQ-treated group was given TQ (50 mg/kg body weight) once a day orally for 12 weeks starting just after toluene exposure. Tissue samples were obtained for histopathological investigation. To date, no histopathological changes of testis in rats after chronic toluene exposure by TQ treatment have been reported. Spermatogenesis and mean seminiferous tubule diameter (MSTD) were significantly decreased in toluene treated groups when compared to the control group. Furthermore, the TQ-treated animals showed an improved histological appearance in toluene-treated group. Our data indicate a significant reduction in the activity of in situ identification of apoptosis using terminal dUTP nick end-labeling (TUNEL), endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS) and there was a rise in the expression of proliferating cell nuclear antigen (PCNA) in testis tissues of the toluene-treated group with TQ therapy. Electron microscopy of the testes of the rats demonstrated that pretreatment with TQ was particularly effective in preventing the mitochondrial degeneration, dilatation of smooth endoplasmic reticulum (SER) and enlarged intercellular spaces in both Sertoli and spermatid cells in the toluene-treated animals. We believe that further preclinical research into the utility of TQ may indicate its usefulness as a potential treatment on the spermatogenesis after testicular injury caused by chronic toluene exposure in rats.

Wang, Guixia;Zhang, Xiuying;Yao, Chunzhu;Tian, Meizhan

doi: 10.1177/0748233710383453pmid: 20858646

Nitrobenzene is a synthetic compound, more than 95% of which is used in the production of aniline. Nitrobenzene has been demonstrated to be substantially metabolized to p-Nitrophenol, p-Aminophenol and p-Nitroaniline in food animals (e.g., bovines, fowls). There have been no studies on the acute toxicity and the mutagenesis of the mixture of the three metabolites mentioned above. The aim of the present study is to testify the acute toxicity and the mutagenesis of the three metabolites mixture. Seventy Kunming mice (half male, half female) received an intragastric administration exposure to metabolites-containing suspension of 750, 638, 542, 461, 392, 333 mg kg-1 body weight and 0.5% sodium carboxymethyl cellulose (control), followed by a 14-day observation. The medial lethal dose (LD 50) concentration for nitrobenzene metabolites mixture in this study was 499.92 mg/kg. Their mutagenic toxicology was studied through micronucleus and sperm abnormality test. Kunming mice were twice intragastrically exposed to 1/5 LD50, 1/10 LD50, 1/20 LD50 mg kg -1 nitrobenzene metabolites-containing suspension spaced 24-h apart. Cyclophosphamide, pure water and sodium carboxymethyl cellulose served as doses of the positive group, the negative group and the solvent control group, respectively. The incidence of micronucleus and sperm abnormality increased significantly in the 1/5 LD50 and 1/10 LD50 group compared with the negative and solvent control group. A dose-related increase in the incidence of micronucleus and sperm abnormality was noted. In conclusion, the three metabolites mixture of nitrobenzene was secondary toxicity and mutagenic substances in mice.

Abrahim, Khadiga S ;Abdel-Gawad, Nadia B ;Mahmoud, Amal M ;El-Gowaily, Mohamed M ;Emara, Ahmed M ;Hwaihy, Mohamed M

doi: 10.1177/0748233710383743pmid: 20870694

Many studies proved the genotoxic effect of cadmium (Cd) exposure and highlighted the importance of the cytogenetic studies as a sensitive and effective means for early detection of Cd-induced mutagenicity. The relationship between occupational exposure to Cd and increased risk of cancer, particularly lung cancer, has been explored in number of epidemiological studies. The aim of this study is to assess the role of chromosomal abnormalities and sister chromatid exchange as sensitive indicators for the genotoxicity of occupational exposure to Cd. Cytogenetic studies was done for 40 workers (27 smokers and 13 non-smokers) exposed to Cd dust and fumes with 40 control subjects (28 smokers and 12 non-smokers) not exposed to Cd before. Both exposed and control groups were similar in age and other sociodemographic factors. Clinical examination, laboratory investigation including urinary and blood Cd, cytogenic analysis for detection of chromosomal aberrations and sister chromatid exchange and environmental study of the work places were done. Statistical analysis of cytogenetic studies revealed the presence of significant elevation of chromosomal aberrations and sister chromatid exchanges of the exposed group. Urinary and blood Cd of the exposed group were significantly higher than that of the control group. These abnormalities were not significantly affected with age, duration of exposure, smoking habits, blood and urinary Cd. In conclusion, the study adds more proof that Cd exposure has a genotoxic effect and highlighted the importance of using cytogenetic studies as a sensitive and effective means for early detection of Cd-induced mutagenicity

Türkan, H. ;Aydin, A. ;Sayal, A. ;Karahalil, B.

doi: 10.1177/0748233710384911pmid: 20935031

The aim of our study was to evaluate the markers of oxidative status of erythrocyte during general anesthesia and compare the markers of oxidative status of erythrocyte in both sevoflurane and desflurane. Venous blood samples of patients were collected the following time intervals; initial time (IT) and first hour (1st h), first (1st day) and third days (3rd day) after anesthesia (sevoflurane and Desflurane). The levels of magnesium (Mg), zinc (Zn) as a cofactor of these enzymes, malondialdehyde (MDA) and the activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) enzymes were also determined. No significant changes were observed in these measurements when the patients were exposed to desflurane anesthesia. On the other hand, the levels of Zn on erythrocytes were significantly increased at 1st hour and 1st and 3rd days compared to initial time in sevoflurane group (p < 0.01, p < 0.01, and p < 0.05, respectively). The activity of GSH-Px was significantly increased (p = 0.05) while the activity of SOD was significantly decreased (p < 0.01) at 1st hour after administration of sevoflurane compared to the initial time. There were no changes on the levels of Mg and MDA. Our results showed that sevoflurane has more impacts on the antioxidant status of erythrocytes than desflurane.