Acellular comet assay: a tool for assessing variables influencing the alkaline comet assay

Phospholipids modifications, genotoxic and anticholinesterase effects of pepper fruit (Dennettia tripetala G. Baker) extract in Swiss mice

The toxicity of D. tripetala fruit extract to mice was investigated using data obtained from lipidomic analyses, comet and Acetylcholinesterase (AChE) assays. Mice (n = 8) were exposed for 30 days via oral gavage to vehicle (5% Tween 80) (negative control), D. tripetala extract (100, 200 and 400 mg/kg) and 40 mg/kg methyl methanesulfonate (MMS) (positive control). The profile of compounds in the fruit extract was analyzed using gas chromatography-mass spectrometry. Out of the total of 32 compounds identified, considerable amount of established insecticidal compounds such as 2-phenylnitroethane, cis-vaccenic acid, linalool and linoleic acid were detected. Fruit extract did not induce DNA damage relative to negative control. Percentage gain in body weights differed significantly across the four weeks. Significantly highest and lowest brain AChE activity was observed in animals exposed to 200 and 400 mg/kg D. tripetala, respectively. Fruit extract modulated the brain phospholipid profile due to significant fold changes of 48 lipid species out of the total of 280 lipid species. High number of differentially expressed phosphatidylcholine (PC) species and significant levels of phosphatidylethanolamine (PE) at 400 mg/kg suggests that activation of inflammation and methylation pathways are the most plausible mechanisms of D. tripetala toxicity to mouse brain tissue.

Effects of Low-Intensity Microwave Radiation on Oxidant-Antioxidant Parameters and DNA Damage in the Liver of Rats

The continuously increasing usage of cell phones has raised concerns about the adverse effects of microwave radiation (MWR) emitted by cell phones on health. Several in vitro and in vivo studies have claimed that MWR may cause various kinds of damage in tissues. The aim of this study is to examine the possible effects of exposure to low-intensity MWR on DNA and oxidative damage in the livers of rats. Eighteen Sprague-Dawley male rats were divided into three equal groups randomly (n = 6). Group 1 (Sham-control): rats were kept under conditions the same as those of other groups, except for MWR exposure. Group 2: rats exposed to 1800 MHz (SAR: 0.62 W/kg) at 0.127 ± 0.04 mW/cm² power density, and Group 3: rats exposed to 2,100 MHz (SAR: 0.2 W/kg) at 0.038 ± 0.03 mW/cm² power density. Microwave application groups were exposed to MWR 2 h/day for 7 months. At the end of the exposure period, the rats were sacrificed and DNA damage, malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), and total oxidant-antioxidant parameter analyses were conducted in their liver tissue samples. It was found that 1800 and 2100 MHz low-intensity MWR caused a significant increase in MDA, 8-OHdG, total oxidant status, oxidative stress index, and comet assay tail intensity (P < 0.05), while total antioxidant status levels (P < 0.05) decreased. The results of our study showed that whole-body exposure to 1800 and 2100 MHz low-intensity MWR emitted by cell phones can induce oxidative stress by altering oxidant-antioxidant parameters and lead to DNA strand breaks and oxidative DNA damage in the liver of rats. Bioelectromagnetics. 2021;42:76-85. © 2020 Bioelectromagnetics Society.

Acetamiprid-induced Cyto- and Genotoxicity in the AR42J Pancreatic Cell Line

Objectives

Neonicotinoid insecticides, 30% of insecticides marketed worldwide, have selective toxicity on insects through α4p2 nicotinic acetylcholine receptors. Although it is known that acetamiprid exerts toxicity on several organ systems, its toxic effects on the pancreas and its mechanism of action have not been clarified yet. Therefore, in the present study, the cytotoxic and genotoxic potentials of acetamiprid on the AR42J pancreatic cell line were evaluated.

Materials and Methods

The (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) (MTT) assay and comet assay were conducted for the cyto- and genotoxicity evaluations, respectively. Reactive oxygen species (ROS) production was assessed by flow cytometry and glutathione (GSH) levels were determined by ELISA for oxidative damage potential, which is thought to be an underlying mechanism of cyto-/genotoxic effects.

Results

To reveal the dose-response relationship the concentration range of 1-6 mM was selected for the assays. Cell viability decreased in a dose-dependent manner and the inhibitory concentration 50 value was calculated as 12.61 mM by the MTT assay. Acetamiprid induced DNA damage in all concentrations tested in a dose-depending manner. The mean tail intensity values were 3.84 and ≤32.96 for the control and exposure groups, respectively. There was no significant difference for ROS production; however, the GSH level was reduced at the highest concentration.

Conclusion

It is thought that the present study will contribute to the literature due to the lack of data on the potential toxic effects of acetamiprid on the pancreas. To better understand acetamiprid toxicity, further studies including a wide range of mechanistic parameters are needed.

Effect of 900-, 1800-, and 2100-MHz radiofrequency radiation on DNA and oxidative stress in brain

Ubiquitous and ever increasing use of mobile phones led to the growing concern about the effects of radiofrequency radiation (RFR) emitted by cell phones on biological systems. The aim of this study is to explore whether long-term RFR exposure at different frequencies affects DNA damage and oxidant-antioxidant parameters in the blood and brain tissue of rats. 28 male Sprague Dawley rats were randomly divided into four equal groups (n = 7). They were identified as Group 1: sham-control, Group 2: 900 MHz, Group 3: 1800 MHz, and Group 4: 2100 MHz. Experimental groups of rats were exposed to RFR 2 h/day for 6 months. The sham-control group of rats was subjected to the same experimental condition but generator was turned off. Specific absorption rates (SARs) at brain with 1 g average were calculated as 0.0845 W/kg, 0.04563 W/kg, and 0.03957, at 900 MHz, 1800 MHz, and 2100 MHz, respectively. Additionally, malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), total antioxidant status (TAS), and total oxidant status (TOS) analyses were conducted in the brain tissue samples. Results of the study showed that DNA damage and oxidative stress indicators were found higher in the RFR exposure groups than in the sham-control group. In conclusion, 900-, 1800-, and 2100-MHz RFR emitted from mobile phones may cause oxidative damage, induce increase in lipid peroxidation, and increase oxidative DNA damage formation in the frontal lobe of the rat brain tissues. Furthermore, 2100-MHz RFR may cause formation of DNA single-strand breaks.