Assessment of Genotoxic Effects of Pendimethalin in Chinese Hamster Over Cells by the Single Cell Gel Electrophoresis (Comet) Assay

Pendimethalin exposure induces bovine mammary epithelial cell death through excessive ROS production and alterations in the PI3K and MAPK signaling pathways

Herbicides are chemicals that have been established to have adverse impacts. However, they are still widely used in agriculture. Pendimethalin (PDM) is an herbicide that is widely used in many countries to control annual grasses. The possibility of livestock being exposed to PDM is relatively high, considering the half-life of PDM and its residues in water, soil and crops. However, the toxicity of PDM in cattle, especially in the mammary glands, has not been reported. Therefore, we investigated whether PDM has toxic effects in the mammary epithelial cells (MAC-T) of cattle. MAC-T cells were treated with various doses (0, 2.5, 5 and 10 μM) of PDM. We found that PDM affected cell viability and cell proliferation and causes cell cycle arrest. Furthermore, PDM triggered cell apoptosis, induced excessive ROS production and mitochondrial membrane potential (MMP) loss, and disrupted calcium homeostasis. In addition, PDM altered the activation of proteins associated with the endoplasmic reticulum (ER) stress response and modified PI3K and MAPK signaling cascades. In conclusion, our current study unveiled the mechanism of PDM in MAC-T cells and we suggest that PDM might be harmful to the mammary gland system of cattle, possibly affecting milk production.

Pesticide Residues in Commonly Consumed Vegetables in Henan Province of China in 2020

Background

Pesticides are widely used in agricultural production to control insect pests and regulate plant growth in China, which may result in the presence of some pesticide residues in the vegetables. However, few studies of monitoring pesticides have been conducted in Henan Province. The aim of this study was to evaluate the level of pesticide residues in commonly consumed vegetables in the regions of Henan Province.

Methods

In this study, we collected 5,576 samples of 15 different vegetables in 17 areas from Henan Province during 2020. Eight kinds of pesticides were analyzed by gas chromatography-mass spectrometry (GC-MS), including procymidone, lambda-cyhalothrin, cypermethrin, pendimethalin, isocarbophos, isazophos, fenthion and deltamethrin. The chi-square test was used to compare the detection rates of pesticide residues in different regions.

Results

Of all the pesticides above, procymidone, lambda-cyhalothrin, cypermethrin, pendimethalin and isocarbophos were detected in vegetables, the detection rates were 27.0%, 16.2%, 11.4%, 3.5%, and 1.9%, respectively. However, isazophos, fenthion, and deltamethrin were not detected. In addition, procymidone, lambda-cyhalothrin, and cypermethrin were detected in urban areas, while pendimethalin was detected in rural areas. The detection rates of cypermethrin and pendimethalin in rural were 19.8% and 5.4%, respectively, which in urban were at relatively lower levels (13.7% and 1.9%, respectively) (P < 0.05). Compared the differences of pesticide detection rates among five areas of Henan province, we found that there were statistical differences in the detection rates of procymidone, cypermethrin and lambda-cyhalothrin in different regions (all P < 0.05).

Conclusion

The results have revealed that the pesticide residues are present. Higher detection rates and more types of pesticides were found in rural areas than urban areas. In addition, there were higher detection rates in Eastern Henan. The findings provided valuable information on the current pesticide residues status, which can be a reference of pesticide supervision and management.

Assessment of the ameliorative effect of curcumin on pendimethalin-induced genetic and biochemical toxicity

The present study aimed to assess the toxic effects of pendimethalin herbicide and protective role of curcumin using the Allium test on cytological, biochemical and physiological parameters. The effective concentration (EC₅₀) of pendimethalin was determined at 12 mg/L by the root growth inhibition test as the concentration reducing the root length by 50%. The roots of Allium cepa L. was treated with tap water (group I), 5 mg/L curcumin (group II), 10 mg/L curcumin (group III), 12 mg/L pendimethalin (group IV), 12 mg/L pendimethalin + 5 mg/L curcumin (group V) and 12 mg/L pendimethalin + 10 mg/L curcumin (group VI). The cytological (mitotic index, chromosomal abnormalities and DNA damage), physiological (rooting percentage, root length, growth rate and weight gain) and oxidative stress (malondialdehyde level, superoxide dismutase level, catalase level and glutathione reductase level) indicators were determined after 96 h of treatment. The results revealed that pendimethalin treatment reduced rooting percentage, root length, growth rate and weight gain whereas induced chromosomal abnormalities and DNA damage in roots of A. cepa L. Further, pendimethalin exposure elevated malondialdehyde level followed by antioxidant enzymes. The activities of superoxide dismutase and catalase were up-regulated and glutathione reductase was down-regulated. The molecular docking supported the antioxidant enzymes activities result. However, a dose-dependent reduction of pendimethalin toxicity was observed when curcumin was supplied with pendimethalin. The maximum recovery of cytological, physiological and oxidative stress parameters was recorded at 10 mg/L concentration of curcumin. The correlation studies also revealed positive relation of curcumin with rooting percentage, root length, weight gain, mitotic activity and glutathione reductase enzyme level while an inverse correlation was observed with chromosomal abnormalities, DNA damage, superoxide dismutase and catalase enzyme activities, and lipid peroxidation indicating its protective effect.

Pendimethalin induces apoptosis in testicular cells via hampering ER-mitochondrial function and autophagy

Pendimethalin (PDM) is a dinitroaniline crop pesticide that is extensively utilized worldwide. However, the reproductive toxicity and cellular mechanisms of PDM have not been identified. Therefore, we elucidated the adverse effects of PDM on the reproductive system using mouse testicular Leydig and Sertoli cells (TM3 and TM4 cells, respectively). Our results demonstrated that PDM suppressed the viability and proliferation of TM3 and TM4 cells. Additionally, PDM induced cytosolic calcium upregulation and permeabilization of mitochondrial membrane potential in both TM3 and TM4 cells. We also verified that PDM activates the endoplasmic reticulum (ER) stress pathway and autophagy. Furthermore, we confirmed that activation of ER stress and autophagy were blocked by 2-aminoethoxydiphenyl borate (2-APB) treatment. Finally, we confirmed PDM-induced cell cycle arrest and apoptosis in TM3 and TM4 cells. Thus, we first demonstrated that PDM impedes the survival of testis cells, and further, their function.

Genotoxic Effects of Etoposide, Bleomycin, and Ethyl Methanesulfonate on Cultured CHO Cells: Analysis by GC-MS/MS and Comet Assay

To evaluate methods for analysis of genotoxic effects on mammalian cell lines, we tested the effect of three common genotoxic agents on Chinese hamster ovary (CHO) cells by single-cell gel electrophoresis (comet assay) and gas chromatography-tandem mass spectrometry (GC-MS/MS). Suspension-grown CHO cells were separately incubated with etoposide, bleomycin, and ethyl methanesulfonate and analyzed by an alkaline comet assay and GC-MS/MS. Although DNA strand breaks were detected by the comet assay after treatment with all three agents, GC-MS/MS could only detect DNA nucleobase lesions oxidatively induced by bleomycin. This demonstrates that although GC-MS/MS has limitations in detection of genotoxic effects, it can be used for selected chemical genotoxins that contribute to oxidizing processes. The comet assay, used in combination with GC-MS/MS, can be a more useful approach to screen a wide range of chemical genotoxins as well as to monitor other DNA-damaging factors.