El ensayo de micronúcleos como medida de inestabilidad genética inducida por agentes genotóxicos

Detection of Mitogenic and Genotoxic Effects of the Turkey Tail Medicinal Mushroom (Trametes versicolor, Agaricomycetes) Extracts from Mexico on Human Lymphocyte Cultures

Diseases caused by a compromised immune system, characterized by decreased production and diversification of T lymphocytes, such as immunodeficiencies or chronic infections, are becoming increasingly prominent. These diseases lead to increased vulnerability to infections caused by parasites, viruses, bacteria, fungi, and other microorganisms. According to various articles, Trametes versicolor has been used as immunotherapy and cancer treatment due to its polysaccharides, which have shown their value in traditional medicine. However, most of the studies have been done with Asian samples. For this reason, the aim of this study was to evaluate the effect of samples of Mexican T. versicolor on human lymphoid cells. Of various extracts, the one with the best T cell proliferative response was the extract produced by maceration in water at room temperature, but all treatments in aqueous and ethanolic extracts increased the lymphocyte count, showing that extracts of Mexican T. versicolor also have compounds that stimulate T cells. Unfortunately, genetic damage expressed as an increment in micronuclei count was identified, so using these fungus extracts in traditional medicine would require careful control of recommended doses.

Evaluation of micronuclei in oral mucosa of individuals exposed to ionizing radiation: a pilot study from Celaya, México

Introduction

Occupational exposure to ionizing radiation can potentially lead to adverse health effects, including cancer and genetic defects. Genetic damage caused by radiation can be detected if micronuclei are observed. The objective of this pilot study was to detect the presence of micronuclei in cells of the oral mucosa in inidividuals occupationally exposed to ionizing radiation.

Methods

We implemented a pilot case-control study in which we compared oral mucosa micronuclei in 30 medical and nursing personnel in radiology centers in Celaya, Mexico, with 30 volunteers not exposed to ionizing radiation recruited from a public University. The oral mucosa was brushed and the amount of micronuclei was quantified. Chi-square test or t-test for two proportions were used to compared ionizing radiation and genetic damage between exposed and non-exposed groups.

Results

The exposed group had an average of 5.37 ± 3.49 micronuclei and the non-exposed had 0.37 ± 0.61 (P<0.01). In the exposed group, 90% of participants exhibited genetic damage compared to 6.67% in the unexposed group (P<0.05).

Conclusion

In this pilot study, medical and nursing staff from radiology centers presented with higher genetic damage compared to control group. Further studies are needed to identify the prevalence of genetic damage due to occupational radiation exposure in Mexico.

Genotoxic effects in oral mucosal cells caused by the use of orthodontic fixed appliances in patients after short and long periods of treatment

OBJECTIVE

This study aimed to evaluate the genotoxic effects in the oral epithelial cells of patients undergoing fixed orthodontic treatment and to compare these to a control group without treatment. The null hypothesis to be tested is that corrective orthodontic treatment at different periods does not cause genotoxic effects in patients.

MATERIAL AND METHODS

An observational cross-sectional study including 74 patients enrolled in corrective orthodontic treatment and 21 control patients, between 11 and 35 years of age, of both genders, participated in the research. Patients undergoing treatment were divided into four treatment groups differentiated by treatment periods: G1, n = 21 (1 month to 12 months); G2, n = 21 (13 to 24 months); G3, n = 23 (25 to 48 months); and G4, n = 9 (over 48 months). Cells were collected by scraping the internal side of the cheek and subsequently placed in tubes containing 0.9% sodium chloride solution. The sample underwent evaluation for genotoxic effects by means of the micronucleus test (MNT). Bivariate analyses were performed using parametric tests (t test or ANOVA) and nonparametric tests (Chi-square test, Kruskal-Wallis test, Dunn post-test). The adopted level of significance was 5%.

RESULTS

Statistically significant differences for any of the genotoxic abnormalities (binucleated, trinucleated, karyolysis, piknosis, nuclear buds) were not found except for karyolysis, which was higher in the control group than in G4 (p < 0.05).

CONCLUSIONS

This study did not demonstrate evidence of genotoxic effects even after long periods of corrective orthodontic treatment.

CLINICAL RELEVANCE

This study explores genotoxic effects in fixed orthodontic patients.

Effect of Moringa oleifera consumption on diabetic rats

BACKGROUND

Therapeutic use of leaves of M. oleifera has been evaluated in diabetes because of its possible capacity to decrease blood glucose and lipids concentration after ingestion, as result of the polyphenols content and others compounds. Nevertheless most results have been obtain from leaf extract, therefore this study would use leaf powder as the regular way of consumption of population to know effects over toxicity glucose, triglycerides, cholesterol, corporal weight, and predominant groups of microbiota.

METHODS

Powdered leaf was administrated in different doses to know toxicity and genotoxicity using LD50 and micronuclei assay. Hyperglycemia was induced by alloxan on Sprague Dawley rats. Glucose and body weight were measured once a week meanwhile cholesterol and triglycerides were analyzed at the end of the study by commercial kits. Different organs were examined by hematoxylin-eosin technique. Lactic acid bacteria and Enterobacteriaceae were enumerated from stool samples.

RESULTS

The tested doses revealed no lethal dose and no significant differences in genotoxicity parameter. The consumption of the leaves showed a hypoglycemic effect (< 250 mg/dL in diabetic M. oleifera treated group), however in corporal weight showed an increased (> 30 g over no M. oleifera treated groups). There was no change in enumeration of lactic acid bacteria (8.4 CFU/g) but there were differences in the predominance of type of lactobacillus and enterobacteria enumeration.

CONCLUSIONS

These results help to increase information over the most popular use of M. oleifera and its safety. However there are needed more studies over the hypoglycemic mechanisms and effects over intestinal microbiota.

Phytotherapeutic approach: a new hope for polycyclic aromatic hydrocarbons induced cellular disorders, autophagic and apoptotic cell death

Polycyclic aromatic hydrocarbons (PAHs) comprise the major class of cancer-causing chemicals and are ranked ninth among the chemical compounds threatening to humans. Moreover, interest in PAHs has been mainly due to their genotoxic, teratogenic, mutagenic and carcinogenic property. Polymorphism in cytochrome P450 (CYP450) and aryl hydrocarbon receptor (AhR) has the capacity to convert procarcinogens into carcinogens, which is an imperative factor contributing to individual susceptibility to cancer development. The carcinogenicity potential of PAHs is related to their ability to bind to DNA, thereby enhances DNA cross-linking, causing a series of disruptive effects which can result in tumor initiation. They induce cellular toxicity by regulating the generation of reactive oxygen species (ROS), which arbitrate apoptosis. Additionally, cellular toxicity-mediated apoptotic and autophagic cell death and immune suppression by industrial pollutants PAH, provide fertile ground for the proliferation of mutated cells, which results in cancer growth and progression. PAHs play a foremost role in angiogenesis necessary for tumor metastasization by promoting the upregulation of metalloproteinase-9 (MMP-9), vascular endothelial growth factor (VEGF) and hypoxia inducible factor (HIF) in human cancer cells. This review sheds light on the molecular mechanisms of PAHs induced cancer development as well as autophagic and apoptotic cell death. Besides that authors have unraveled how phytotherapeutics is an alternate potential therapeutics acting as a savior from the toxic effects of PAHs for safer and cost effective perspectives.

Micronucleated Erythrocytes in Peripheral Blood from Neonate Rats Exposed by Breastfeeding to Cyclophosphamide, Colchicine, or Cytosine-Arabinoside

Genotoxic exposure to chemical substances is common, and nursing mothers could transmit harmful substances or their metabolites to their offspring through breast milk. We explored the possibility of determining genotoxic effects in the erythrocytes of breastfeeding rat pups whose mothers received a genotoxic compound while nursing. Ten groups of female rats and five pups per dam were studied. The control group received sterile water, and the experimental groups received one of three different doses of cyclophosphamide, colchicine, or cytosine-arabinoside. Blood smears were prepared from samples taken from each dam and pup every 24 h for six days. There were increased numbers of micronucleated erythrocytes (MNEs) and micronucleated polychromatic erythrocytes (MNPCEs) in the samples from pups in the experimental groups (P < 0.02) and increased MNPCE frequencies in the samples from the dams (P < 0.05). These results demonstrate the vertical transmission of the genotoxic effect of the compounds tested. In conclusion, assessing MNEs in breastfeeding neonate rats to assess DNA damage may be a useful approach for identifying genotoxic compounds and/or cytotoxic effects. This strategy could help in screening for therapeutic approaches that are genotoxic during the lactation stage and these assessments might also be helpful for developing preventive strategies to counteract harmful effects.

Common toad Rhinella arenarum (Hensel, 1867) and its importance in assessing environmental health: test of micronuclei and nuclear abnormalities in erythrocytes

Anthropogenic activities may generate significant changes in the integrity of aquatic ecosystems, so long-term monitoring of populations that inhabit them is crucial. Counting micronucleated erythrocytes (MN) and erythrocytic nuclear abnormalities (ENA) in peripheral blood is a widely used method for detecting chromosomal damage due to chemical agents in the water. We analyzed MN and ENA frequency in blood obtained from the common toad Rhinella arenarum populations in sites with different degrees of environmental degradation. The results of this study indicate that there is an association between the frequency of micronuclei and nuclear abnormalities and the degree of environmental alteration recorded for the sites studied.

Occupational exposure of workers to pesticides: Toxicogenetics and susceptibility gene polymorphisms

Farm workers are often exposed to pesticides, which are products belonging to a specific chemical group that affects the health of agricultural workers and is mostly recognized as genotoxic and carcinogenic. The exposure of workers from Piauí, Brazil, to these hazardous chemicals was assessed and cytogenetic alterations were evaluated using the buccal micronucleus assay, hematological and lipid parameters, butyrylcholinesterase (BChE) activity and genetic polymorphisms of enzymes involved in the metabolism of pesticides, such as PON1, as well as of the DNA repair system (OGG1, XRCC1 and XRCC4). Two groups of farm workers exposed to different types of pesticides were evaluated and compared to matched non-exposed control groups. A significant increase was observed in the frequencies of micronuclei, kariorrhexis, karyolysis and binucleated cells in the exposed groups (n = 100) compared to controls (n = 100). No differences were detected regarding the hematological parameters, lipid profile and BChE activity. No significant difference was observed either regarding DNA damage or nuclear fragmentation when specific metabolizing and DNA repair genotypes were investigated in the exposed groups.

Fruit extract from a Sechium edule hybrid induce apoptosis in leukaemic cell lines but not in normal cells

The antiproliferative potential of a crude extract from the chayote hybrid H-837-07-GISeM® and its potential for apoptosis induction were assessed in leukaemic cell lines and normal mouse bone marrow mononuclear cells (BM-MNCs). The extract strongly inhibited the proliferation of the P388, J774, and WEHI-3 cell lines (with an IC50 below 1.3 μg·mL(-1)), reduced cell viability, and induced apoptotic body production, phosphatidylserine translocation, and DNA fragmentation. However, the extract had no effect on BM-MNCs. We postulate that these properties make the extract a good candidate for an anti-tumour agent for clinical use.

Emissions generated by sugarcane burning promote genotoxicity in rural workers: a case study in Barretos, Brazil

BACKGROUND

To determine the possible genotoxic effect of exposure to the smoke generated by biomass burning on workers involved in manual sugar cane harvesting.

METHODS

The frequency of micronuclei in exfoliated buccal cells and peripheral blood lymphocytes was determined in sugarcane workers in the Barretos region of Brazil, during the harvest season and compared to a control population, comprised of administrative employees of Barretos Cancer Hospital.

RESULTS

The frequency of micronuclei was higher in the sugar cane workers. The mean frequency in blood lymphocytes (micronuclei/1000 cells) in the test group was 8.22 versus 1.27 in the control group. The same effect was observed when exfoliated buccal cells were considered (22.75 and 9.70 micronuclei/1000 cells for sugar cane workers and controls, respectively).

CONCLUSION

Exposure to emissions produced by the burning of sugar cane during harvesting induces genomic instability in workers, indicating the necessity of adopting more advanced techniques of harvesting sugar cane to preserve human health.

Effects of pneumonia and malnutrition on the frequency of micronuclei in peripheral blood of pediatric patients

The aim of this study was to evaluate the effects of bacterial pneumonia and malnutrition on the frequency of micronuclei (MN) in peripheral blood of pediatric patients through flow cytometric analysis. The study was an analytical case-control study carried out on 35 malnourished children with bacterial pneumonia and 20 well-nourished children with bacterial pneumonia, in addition to 20 healthy children as controls. Complete physical examination including; anthropometric measurement, Chest roentgenograms were done for all cases. Assessment of MN was done by FACSCalibur flow cytometry. The frequency of micronucleated reticulocytes (MN-RETs) was higher both in the malnourished children with pneumonia and well-nourished children with pneumonia than the controls. Within the malnourished children with pneumonia, patients with kwashiorkor had more micronucleated mature erythrocytes (MN-RBCs) and MN-RETs than patients with marasmus.

IN CONCLUSION

Pneumonia is associated with an increased frequency of MN and this increment is more pronounced in children with severe malnutrition especially kwashiorkor group.