Iranian Journal of Toxicology
Volume:13 Issue: 3, Jul 2019

The mechanism of para-nonylphenol (PNP) reducing the proliferation and differentiation of bone marrow mesenchymal stem cells (MSCs) is not known. The present study was designed to investigate the mechanism. MSCs were extracted under sterile condition from Wistar rat and cultured in DMEM, containing 15 % FBS and penicillin/streptomycin until the 3rd passage, then cells were treated with 0, 0.5 and 2.5 µM of PNP for 5, 10, 15 and 20 days. We studied the viability, proliferation, cell cycle and morphology of the cells. In addition, the concentration of total protein, sodium, potassium and calcium and the activity of metabolic enzymes (ALT, AST and LDH) were determined. Also, induction of oxidative stress was estimated by determining the total antioxidant and MDA levels in addition to the activity of SOD and CAT. The concentrations of PNP caused a significant increase in metabolic enzymes activity and reduced the total protein dose dependently from day 5 to day 20. But only the higher PNP concentration reduced the sodium level and increased the calcium concentration during the treatment period. In addition, we observed a significant decrease in the total antioxidant level and of SOD and CAT activities whereas a significant increase in MDA was seen. Also, PNP stopped the cell cycle at “S” and “G2/M” phases. Para-NP, used in many industries, was able to reduce the viability and proliferation of the MSCs via metabolic and electrolyte imbalance and by induction of oxidative stress and cell cycle disruption.

Lead is a major environmental pollutant and can adversely affect humans and animals. There are conflicting data about the ototoxic effect of lead. This study experimentally examined the association between blood lead levels (BLL) and the subsequent hearing impairment in male rats. Twenty-two male rats were randomly categorized into experimental (exposed to lead acetate, 4 mg/kg by gavage) and control groups. We evaluated the groups by click and tone audiometric burst tests, comparing the data before and 30 days after exposure to lead acetate (4mg/kg). Also, blood samples were collected from the rats and analyzed for lead levels by graphite furnace atomic absorption spectrometry. The study findings demonstrated remarkable increase in hearing threshold in the lead-exposed group, compared to the controls (p<0.0001). Also, the blood lead levels revealed a significant association of lead acetate with the hearing loss in rats. This study revealed that exposure to lead acetate can be damaging to hearing. However, future research is recommended to clarify the mechanism of action of lead toxicity on the auditory function at varying blood lead concentrations.

Lead is known to be a highly toxic heavy metal which has a wide range of effect on human health. It has been proven that probiotics are able to bind heavy metals and remove them from the environment. In this study, the effect of Lactobacillus fermentum (L. fermentum) and its cytoplasmic extract were investigated on the hematological and body weight parameters in lead exposed rats. Forty eight rats were divided into 6 groups of eight as follows: Group 1: controls; Group 2: treated with lead acetate; Group 3: treated with L. fermentum; Group 4: treated with lead acetate and intact L. fermentum bacteria; Group 5: treated with the extracts of L. fermentum; Group 6: treated with lead acetate and the extract. At the completion of the experiments, rats’ blood samples were collected and analyzed for the hematological parameters. The lead concentrations were measured in the fecal pellets.  
The results demonstrated significant differences among the hematological parameters in groups 2 and 6, compared with those in the controls. However, no significant differences were detected for the parameters in groups 3, 4 and 5.  The lead concentrations in the fecal pellets of group 4 animals showed a significant increase compared to those recorded for the groups that were exposed to lead acetate. The findings suggest that L. fermentum may inhibit or minimize the harmful effects of lead on rat’s hematological parameters by binding to the heavy metal and removing it from the body.

Water plays an essential role in supporting life on earth and sea worldwide, requiringclean, safe, high quality and sustainable resources. Nowadays, many water resources have been contaminatedwith toxic compounds originating from petroleumdue to economical and industrial developments. There is anurgent need to clean up the waters with environmentally friendlyand inexpensive methods. This study investigated the biodegradation of total petroleum hydrocarbons (TPH) using Pseudomonas aeruginosa (P. aeruginosa) in southern Caspian Sea coastline. Coastline sediment samples were collected, with P. aeruginosa being the predominant strain. The bacteria were cultured in triplicates in the presence of 0.5, 1, 2 and 4% of gasoline andunder specific experimental conditions of varying temperature, pH, salinity, shaker speed, and incubation periods. The data representing the gasoline biodegradation in the samples were statistically analyzed.  
At optimized experimental conditions for temperature, pH, salinity, incubation period, and shaker speed, maximum biodegradation of TPH was achieved by culturing P. aeruginosa strains with the sea water samples containing varying concentrations of gasoline. The gram-negative bacteria, P. aeruginosa, almost completely biodegraded TPH contaminants from the samples’ culture media over 28 days of incubation. We conclude that the use of P. aeruginosa is an efficient method for the biodegradation of Caspian coastal waters contaminated with TPH.

This study investigated the concentration of some heavy metals in plastic housing of televisions produced over three decade (1980-2000) with the aim of providing information and comparing the trend in the concentration of these metals. The heavy metal concentrations were determined by atomic absorption spectroscopy after acid digestion using a 1:1 mixture of sulphuric and nitric acid.  
The mean concentration of the heavy metals (mg/kg) in the television sets for 1980s, 1990s and 2000s, respectively, were as follows: 12.75 (Nd); 1.32 (Pb); 1.84, 1.47 & 2.79 (Ni); 1.53, 16.19 & 40.42 (Ag); 82.24, 159.69 & 113.29 (Zn); 7.12, 4.23 & 5.26 (Cr); 3.26, 2.76 & 2.39 (Cu); 4.84, 24.05 & 26.67 (V); 9.30, 8.40 & 12.63 (Co); 2.59, 4.05 & 4.28 (Cd). Although the mean concentrations for Zn, Cu and Ag in the television samples were relatively high, compared to the total threshold limit concentration (TTLC), they were below the threshold limit. These results suggest that there may not be any immediate environmental hazard posed from the TV plastic housings. The correlations analysis showed that most of the metals declined in TV housings over the subsequent decades.

The application of nano-particles (NPs) in various industries is growing. Since their toxicity is not clearly understood, they can cause adverse effects on the environment. The aim of this study was to evaluate the histopathological effects of iron oxide nano-particles on the small intestine of common carp, Cyprinus carpio. Four experimental treatments were designed (15 fish/treatment). Treatment 1 was the controls while Treatments 2, 3 and 4 were experimental. The experimental groups were exposed to 50, 75 and the 100 mg/L of iron oxide NPs, respectively. On days 14, 21 and 28, the fish were randomly picked from each tank, samples of the small intestine were dissected, and were examined for both the accumulation of the iron NPs and the tissue histopathologies.    
The highest concentration of iron accumulation was detected for Treatment 3 on day 21, compared to all other treatment groups (p<0.05). However, iron accumulation in the tissue declined unexpectedly after day 21 despite the continued treatments at 100 mg/L of the iron NPs. The histopathological examinations revealed that the treatment beyond 21 days caused damages to the intestinal epithelial cells, including enterocytes, villi and the goblet cells. This study demonstrated that the effect of iron oxide NPs on the small intestinal tissue was dependant on the dose and duration of exposure. We conclude that the iron accumulation in the small intestine declined despite increasing the iron oxide NPs concentration and the exposure duration secondary to damages caused to the intestinal epithelial cell layer.

Cadmium toxicity has been shown in aquatic animals but the effect on frog’s endocrine glands is not known. We investigated the effects of cadmium on ultimobranchial and parathyroid glands of Indian skipper frog, Euphlyctis cyanophlyctis. Frogs were exposed to cadmium chloride for short and long terms and sacrificed after 24, 48, 72 or 96 h (short-term) and after 5, 10, 15 and 30 days (long-term). After 48h of cadmium exposure, serum calcium levels decreased and persisted for 96h. After 96h of exposure, weak staining of the ultimobranchial cells was noted, and the nuclear volumes decreased. The histological structures of parathyroid cells remained unchanged.
Frogs exposed to cadmium exhibited decreased serum calcium levels from day 10 to day 30.  After 15 days of cadmium exposure, ultimobranchial cells exhibited a decline in staining response and the nuclear volume also decreased. The follicular epithelia of the ultimobranchial glands appeared to be reduced at certain areas. After 30 days of cadmium exposure, the nuclear volume was further decreased and the follicular epithelia shrunk and appeared as a single layer. Cellular degeneration and vacuolization were also noticed in the gland. After day 15 of cadmium exposure, the nuclear volume of the parathyroid cells increased with elongated and hyperchromatic appearance. These changes were exaggerated on day 30 of cadmium exposure and few cell lyses appeared among parathyroid cells. Cadmium adversely affected the calcium regulating glands, ultimobranchial and parathyroid glands of the Indian frogs, Euphlyctis cyanophlyctis.

Air fresheners are products with fragrances used to mask unpleasant odor in the environment. However, air fresheners contain diverse chemical substances that pose health challenges to the users; hence are of public health significance. Although previous studies have shown that air fresheners affect the lungs, liver and reproductive organs, the neurobehavioral effects of these agents are yet to be evaluated in details. This study evaluated the neurobehavioral effects and biochemical changes in mice exposed to a solid commercially available air freshener (SAF). Male Swiss mice were divided into 6 groups (n = 7). Mice in groups 2-6 were exposed to powdered SAF (10, 25, 50, 100 and 200 g) via inhalation in their cages for 28 days. Mice in group 1 (control) were not exposed to SAF. The neurobehavioral changes: spontaneous motor activity (SMA), memory, anxiety and depression were evaluated on day 28. The mice brains were then proccessed for determination of malondialdehyde, nitrite, glutathione contents, and the activities of catalase and acetyl-cholinesterase.  
SAF (25-200g) significantly (p<0.05) impaired SMA compared with control. Mice exposed to SAF exhibited increased anxiety and depression-like symptoms relative to control (p<0.05). It also impaired memory and increased acetylcholinesterase activity (p<0.05). Moreover, SAF increased the levels of nitrite and malondialdehyde accompanied by decreased antioxidant molecules (glutathione and catalase) in mouse brain. These findings suggest that SAF produced neurobehavioral deficits, increased oxidative stress and altered cholinergic system, posing potential health hazards to the regular consumers.