Subacute genotoxicity of acetamiprid in somatic cells of Swiss albino male mice

Pesticides are applied to plants all over the world to boost food production and lower the spread of diseases carried by insects. Exposure to the pesticides may cause genotoxic effects on target and non-target organisms, including humans. In agriculture, acetamiprid (ACE), a neonicotinoid insecticide, is frequently applied either alone or in conjunction with other pesticides. A combined approach employing the micronucleus test (MNT) and chromosomal aberrations (CAs) assay was used to evaluate the genotoxic effects of acetamiprid in the bone marrow of male Swiss albino mice. Acetamiprid was administered i.p. daily at 4.6 and 2.3 mg/kg/day along with 3% gum acacia as a negative control for 30 days. ACE treatment resulted in a small dose dependent increase in the frequencies of micronuclei per cell (0.28 ± 0.04, 0.38 ± 0.03, and 0.45 ± 0.02 for the control, 2.3 and 4.6 mg/kg b.wt. groups, respectively) and chromosomal aberrations (3.67 ± 0.61, 5.00 ± 0.45, and 7.00 ± 1.43 for the control, 2.3 and 4.6 mg/kg b.wt. groups, respectively) in bone marrow cells, but no significant differences were observed between these data sets. In conclusion, daily i.p. exposure of ACE @ 2.3 and 4.6 mg/kg b.wt. for 30 days did not produce significant genotoxic effects in the somatic cells of Swiss albino male mice.

Studies on ameliorative potentials of quercetin nanoparticles against imidacloprid induced subacute genotoxicity and histopathological alteration in Swiss albino mice

OBJECTIVE

Genotoxicity assays include micronucleus test, comet assay, and malformed sperm head used to investigate the protective potential of quercetin (Que) and Que nanoparticles against imidacloprid (IMI)-induced genotoxicity in Swiss albino mice.

METHODS

The ionic gelation procedure was used to synthesize the Que nanoparticles and characterized for their hydrodynamic diameter, zeta potential, scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR, and encapsulation efficiency. A total of 48 mice were taken in eight groups with six animals in each group. Groups 1, 2, 3, and 4 received 3% gum acacia, 22 mg/kg IMI, 25 mg/kg Que and 25 mg/kg Que nanoparticles high dose (QNPs (HD)), respectively. Groups 5, 6, 7, and 8 received 22 mg/kg IMI + 25 mg/kg Que (IMI + Que), 22 mg/kg IMI + 25 mg/kg Que nanoparticles (IMI + QNPs (HD)), 22 mg/kg IMI + 12.5 mg/kg Que nanoparticle medium dose (IMI + QNPs (MD)), and 22 mg/kg IMI + 6.25 mg/kg Que nanoparticles low dose (IMI + QNPs (LD)), respectively.

RESULTS

The IMI causes genotoxicity in bone marrow cells by increasing the frequency of micronuclei and the comet tail length. Additionally, IMI is mutagenic to germ cells, as determined by a test for aberrant sperm heads. Both Que and Que nanoparticles lessen the genotoxicity that IMI induces when administered together or separately. Histopathological findings also revealed degenerative changes in bone marrow and testes in IMI administered group as compared to control.

CONCLUSION

Quercetin and Que nanoparticles showed marked ameliorative effect by restoring the degenerative changes produced by IMI.

Assessment of Cytogenetic Damage and Cholinesterases' Activity in Workers Occupationally Exposed to Pesticides in Zamora-Jacona, Michoacan, Mexico

Pesticides have been considered as potential chemical mutagens; however, little is known about toxic and genotoxic effects during pesticide application in Zamora-Jacona, Michoacan State in Mexico. This study sought to determine DNA damage and cholinesterase activities inhibitions in 54 agricultural workers exposed to complex mixtures of pesticides vs. control group (26 individuals) using Comet assay in peripheral whole blood, micronucleus (MN) test in oral mucosa cells, Cytokinesis-blocked MN assay in lymphocytes (L-CBMNcyt) and measuring AChE and BChE activities in whole blood and plasma samples, respectively. Exposed subjects demonstrated significantly elevated levels of primary (Comet assay: tail intensity, tail length, tail moment, Olive tail moment) and permanent DNA damage (MN assay: in blood/buccal cells; frequencies of nuclear buds, binucleated cells, cells with condensed chromatin, karyorrhexis, pyknosis, and karyolysis). However, inhibition of cholinesterase activities (AChE and BChE) was not observed in the workers. Confounding factors including sex, age, BMI, working exposure period, protection level, smoking habit (cigarettes per day units), alcohol consumption (weekly), medication, were considered in the analysis. These combined techniques demonstrated usefulness in the health hazards risks pesticide exposure assessment and suggested the need for periodic monitoring together with the education and the training of occupational workers for the safe application of potentially harmful pesticides.

Assessment of anilofos-induced mutagenicity in bone marrow and germ cells of Swiss albino mice

Anilofos is an organophosphate compound and is used extensively as a preemergence and early postemergence herbicide for the management of sedges, annual grasses, and some broad-leaved weeds in rice fields. The present study was aimed to assess the mutagenic potential of anilofos after sub-chronic exposure in Swiss albino mice. For this, a combined approach employing micronucleus (MN), chromosomal aberration (CA) studies and sperm-head abnormalities (SHAs) was used. Three dose levels of 1%, 2%, and 4% of maximum tolerated dose (MTD) (235 mg/kg b.wt.), that is, 2.35, 4.7 and 9.4 mg/kg b.wt., respectively, were administered orally daily for 90 days. A higher incidence of micronucleated erythrocytes (polychromatic erythrocytes + normochromatic erythrocytes), significant increase in CA frequency, and significant decrease in the ratio of polychromatic/normochromatic erythrocytes (P/N) ratio were observed at the 4.7 and 9.4 mg/kg b.wt. dose levels. A significant increase in SHA was observed in all treatment groups (2.35, 4.7, and 9.4 mg/kg b.wt.) from the control group. In conclusion, anilofos exposure of 2% and 4% of MTD caused a higher rate of micronucleated erythrocytes, increased frequency of CA, increase in SHA, and lower P/N ratio, and pesticide exposure of 1% of MTD only resulted in higher SHAs. Thus, anilofos was found to have mutagenic potential in mice when administered daily orally at dose rate of 4.7 and 9.4 mg/kg b.wt. for 90 days.

Pesticide handling practices and self-reported morbidity symptoms among farmers

Amid growing concern about the adverse effects of pesticides, a questionnaire-based cross-sectional study was conducted to evaluate farmers' knowledge on pesticides handling. Results of in-depth surveys (n = 217) with field observations revealed that participants had a mean 18 years of farming experience and knapsack-sprays were used for spraying. About 99% were not using any personal-protective-equipments during mixing, loading, application operations. Over 80% reentered the treated farms within two-days of application without following safety protocols and 39% admitted unsafe disposal of empty containers of pesticides. Statistical-analysis revealed a significant association between participant's pesticide handling practices and self-reported morbidity symptoms (p < 0.05). Despite awareness of toxicity, participants were mishandling the pesticides. Training on safe handling practices and incentives in form of personal-protective-equipments could be productive to ensure safety at work.

Assessment of chromosomal aberrations among agricultural workers exposed to pesticides in Punjab, India

Chromosomal aberrations (CAs) are an important tool for assessment of exposure to pesticides. Genotoxic potential of pesticides is a principal risk factor for long-term health effects. The present study was aimed toward the assessment of CAs among agricultural workers exposed to pesticides and comparison with nonagricultural workers not exposed to pesticides. A total of 296 subjects were enrolled in the study: exposed (n = 148) and nonexposed subjects (n = 148) from Punjab. A significantly high frequency of aberrations was seen in peripheral blood lymphocytes of exposed subjects as compared with nonexposed ones. Most CAs were present as loss (aneuploidy) and were observed significantly in subjects having a history of alcohol consumption. It can be, thus, concluded that agricultural workers exposed to a mixture of pesticides, in addition to being alcoholic, are at a greater risk of genotoxic damage. It is highly recommended that the agricultural workers are educated regarding the potential hazards of occupational exposure to pesticides.

Comprehensive assessment of unutilized and obsolete pesticides impact on genetic status and health of population of Almaty region

The group of persistent organic pollutants (POPs) are particularly dangerous for the environment and by consequence for human health because of the risk to be transmitted in the food chain. Among them, the urgent problem of obsolete and forbidden organochlorinated pesticides (OCPs) needs a rigorous management in many countries, including Kazakhstan. The aim of our study was to evaluate the effect of pesticides content in food products on the genetic status and health of the population living on the contaminated areas near destroyed warehouses for OCPs (4 villages of Talgar district and 1 control site, Almaty region). The food products sampled in Taukaraturyk (control site), and in 4 villages where non-utilized obsolete pesticides were discovered: Beskainar, Kyzylkairat, Amangeldy, and Belbulak. The contents of 24 pesticides in food products from plant (apples, pears, tomatoes, cucumbers, sweet peppers) and animal (beef meat, cow milk, honey) origin, that grown in places of localization of non-utilized OCPs, were determined, sometimes in high and unacceptably high concentrations (before 2500 times over MRL). In pears, the pesticides content (especially DDT, γ-HCH, β-HCH, endosulfan, and aldrin pesticide group), was higher than in other fruits. Among vegetables, the highest levels of all groups of pesticide were found in cucumbers. Beef meat samples demonstrated increased contents of β-HCH, γ-HCH, endrin and dieldrin. In cow milk samples only the high concentration of dieldrin was found. The content of pesticides in meat was 4-5 times higher than in milk. The medical examinations, carried out among the cohorts living around the polluted by pesticides territories and control cohort from ecologically favorable village, showed that there were more individuals with high and middle levels of somatic health in the control group than in groups exposed to OCPs. The long-term effect of the pesticide contamination of the environment on genetic status of the population was assessed by chromosomal aberration (CA) frequencies. The highest level of chromosomal aberrations was identified for the examined residents of Kyzylkairat (41%) and Belbulak (38%), a high level in Amangeldy (12%), and middle level in Beskainar (6.5%). The association between the CA frequency, health status and the pesticides contents in food were assessed by a Spearman rank correlation. The low indicators of somatic health status were strictly associated with high levels of CA, and good health status indicates that the CA rates did not exceed the spontaneous level of mutagenesis. The strongest correlation was shown between high levels of chromosomal aberrations and the content of different pesticides in pears (Cr = 0.979-0.467), tomatoes (Cr = 0.877-0.476), cucumbers (Cr = 0.975-0.553) and meat (Cr = 0.839-0.368). The obtained results highlight the need to improve health protection by increasing the public awareness to the security of the storage of obsolete OCPs in order to strengthen food safety by efficient control services.

Micronucleus frequency is correlated with antioxidant enzyme levels in workers occupationally exposed to pesticides

Oxidative stress can cause DNA damage leading to nuclear anomalies such as micronuclei (MN). Antioxidant enzymes involved in protection against intracellular oxidative stress include glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), and catalase (CAT). Pesticide exposure induces oxidative stress and alters antioxidant defense mechanisms, including detoxification and scavenger enzymes. The aim of this study was to evaluate MN frequency in workers occupationally exposed to pesticides and their relationship with antioxidant enzyme activities. A cross-sectional study was conducted in 201 individuals, some of whom were dedicated to the spraying of pesticides. The cytokinesis-block micronucleus (CBMN) assay was conducted, and the activities of GPx, GR, SOD, and CAT were determined. The geometric mean (GM) of MN was 5.4 (1-26 MN). The GM for the antioxidant enzymes was 198.68 U/mL for GPx, 38.96 U/g Hb for GR, 94.78 U/mL for SOD, and 69.77 U/g Hb for CAT. There was a lower MN frequency in males than that in females, and a higher nuclear index. In addition, age affected MN frequency. There was a negative correlation between MN frequency and GPx activity, but a positive one between MN frequency and GR activity. These findings suggest the involvement of GPx in MN frequency.

Association of genetic polymorphisms of telomere binding proteins with cholinesterase activity in omethoate-exposed workers

Omethoate, an organophosphorous pesticide, can cause a variety of health effects, especially the decrease of cholinesterase activity. The aim of this study is to explore the association of genetic polymorphisms of telomere binding proteins with cholinesterase activity in omethoate-exposed population. Cholinesterase activities in whole blood, red blood cell and plasma were detected using acetylthiocholine and dithio-bis-(nitrobenzoic acid) method; Genetic Genotyping of POT1 rs1034794, POT1 rs10250202, TERF1 rs3863242 and TERT rs2736098 were performed with PCR-RFLP. The cholinesterase activities of whole blood, red blood cells and plasma in exposure group are significantly lower than that of the control group (P < 0.001). Multivariate analysis indicates that exposure group (b = - 1.016, P < 0.001), agender (b = 0.365, P < 0.001), drinking (b = 0.271, P = 0.004) and TERF1rs3863242 (b = - 0.368, P = 0.016) had an impact on cholinesterase activities. The results suggest that individual carrying AG+GG genotypes in TERF1 gene rs3863242 polymorphism were susceptible to damage in cholinesterase induced by omethoate.

Cross-sectional associations between genetic polymorphisms in metabolic enzymes and longer leukocyte telomere length induced by omethoate

Purpose

This study aimed to explore the effects of genetic polymorphisms in metabolic enzymes on relative telomere length changes and explore the mechanism of canceration induced by omethoate.

Materials and Methods

180 long-term omethoate-exposed workers and 115 healthy controls were recruited. Real-time PCR method was applied to determine the relative telomere length in peripheral blood leukocytes DNA, and Six polymorphic loci of GSTT1(+/−), GSTM1(+/−), GSTP1 rs1695, CYP2E1 rs6413432, CYP2E1 rs3813867 and PON2 rs12026 were detected by polymerase chain reaction and restriction fragment length polymorphism method; Multiple linear regression was conducted to explore the effects of omethoate exposure and genetic polymorphisms on the telomere length.

Results

The relative telomere lengths in the control group (0.94 [0.76, 1.32]) were significantly shorter than that in the exposure group (1.50 [1.11, 2.57]) (Z = 7.910, P < 0.001). Univariate analysis showed that the relative telomere lengths of the GSTM1-deletion individuals were significantly longer than that of the non - deletion genotype in the control group (Z = 2.911, P = 0.004), and the relative telomere lengths of GSTP1 rs1695 polymorphism locus (GG+AG) genotype individuals were longer than that of AA genotype in the exposure group. The difference was statistically significant (Z = 2.262, P = 0.024). Multivariate analysis found that pesticide-exposure (b = 0.524, P < 0.001) and GSTM1 polymorphism (b = −0.136, P = 0.029) had an impact on telomere length.

Conclusions

The relative telomere lengths of omethoate-exposure workers were longer than that in the control population. Also GSTM1 genetic polymorphism may influence the changes of the telomere length induced by omethoate.

Changes in the expression of genes involved in cell cycle regulation and the relative telomere length in the process of canceration induced by omethoate

Organophosphorous pesticides (OPs), with high efficiency, broad-spectrum and low residue, are widely used in China. Omethoate is a broad category of organophosphorous pesticides and is more domestically utilized which has chronic toxic effect on human health caused by long-term, low-dose exposure to Ops, recently its potential genotoxicity has attracted wide attention which can cause chromosomal DNA damage. Thus, the aim of this study is screen susceptible biomarkers and explore the mechanism of canceration induced by omethoate. 180 long-term organophosphorus pesticide-exposed workers and 115 healthy controls were recruited. Quantitative polymerase chain reaction method was applied to determine the relative telomere length in peripheral lymphocyte DNA as well as p53 and p21 gene expression levels. Genetic polymorphisms were determined by the polymerase chain reaction-restriction fragment length polymorphism method. Multiple linear regression was conducted to explore the effects of exposure, expression levels, and polymorphisms in genes on the telomere length. The results showed the relative telomere lengths in the exposure group were significantly longer than that in the control group. The messenger RNA expression levels of p53 and p21 in exposure group were significantly lower than that in the control group; telomere lengths of the CA genotype individuals of p21 rs1801270 polymorphism locus were significantly longer than that of the CC genotype in the control group that were estimated using the Bonferroni method; and bivariate correlation analysis showed that the messenger RNA expression level of gene p53 was negatively correlated with telomere length, and the messenger RNA expression level of gene p21 was positively correlated with telomere length. Multivariate analysis found that p53 messenger RNA and p21 messenger RNA had an impact on telomere length. These results demonstrated that the messenger RNA expression levels of p53 and p21 may have a relationship with the changes in telomere length induced by omethoate and provided strong evidence for the mechanism of canceration induced by poison.

The use of the lymphocyte cytokinesis-block micronucleus assay for monitoring pesticide-exposed populations

Pesticides are widely used around the world, and hundreds of millions of people are exposed annually in occupational and environmental settings. Numerous studies have demonstrated relationships between pesticide exposure and increased risk of cancers, neurodegenerative and neurodevelopmental disorders, respiratory diseases and diabetes. Assessment of genotoxicity of pesticides and biomonitoring their effect in exposed populations is critical for a better regulation and protection, but it can be complicated because pesticides are often used as complex mixtures. The cytokinesis-block micronucleus assay in human lymphocytes (L-CBMN) is a validated method of assessment of DNA damage induced by clastogenic and aneuploidogenic mechanisms. The goal of this review is to provide an updated summary of publications on biomonitoring studies using this assay in people exposed to pesticides in different settings, and to identify gaps in knowledge, and future directions. A literature search was conducted through MedLine/PubMed and TOXLINE electronic databases up to December 2015. A total of 55 full-text articles, related to 49 studies, excluding reviews, were selected for in depth analysis, divided by the settings where exposures occurred, such as chemical plant workers, pesticide sprayers, floriculturists, agricultural workers and non-occupationally exposed groups. Majority of studies (36 out of 49) reported positive findings with L-CBMN assay. However, most of the studies of professional applicators that used single pesticide or few compounds in the framework of specific programs did not show significant increases in MN frequency. A decreased level of pesticide-induced genotoxicity was associated with the proper use of personal protection. In contrast, subjects working in greenhouses or during intensive spraying season and having acute exposure, showed consistent increases in MN frequency. Overall, this analysis confirmed that L-CBMN is an excellent tool for pesticide biomonitoring, and can validate the effects of educational and intervention programs on reducing exposure and genetic damage.