Micronuclei In Blood Cells Research Articles

Herbicide paraquat dichloride augments the expression of the c-abl-noxa-apoptotic pathway, instigating ovarian atresia in edible fish, Channa punctatus.

Ovarian cells of animals undergo atresia to regulate egg numbers and their release. However, unrestrained atretic activity decreases the chances of oocyte maturity and further process, ultimately resulting in a reduced population. Edible fishes are a critical source of nutrition and it is required to regulate their population. The application of herbicides at fish production sites is a threat to their population by altering female reproductive activity. In concern to this, here, this 60-day study investigates herbicide paraquat dichloride (PD)-induced atresia in ovarian cells of Channa punctatus (C. punctatus). Further, 96-h LC50 of PD for C. punctatus was calculated as 58.40mg/L. At the end of each exposure period, an increase in intracellular ROS in blood cells and activities of SOD and CAT in ovary tissue were observed in PD-treated fish with increasing concentration. The frequency of micronuclei in blood cells subsequently increased with the highest PD concentration. A significant (p < 0.05) increase in the relative expression of target genes was observed at the 30th and 60th day of the sampling periods in the fish treated with the highest concentration of PD. The histological study confirmed the occurrence of atretic ovary cells in PD-exposed fish. From the results it can be concluded that PD enhances the uncontrolled death of ovarian cells and has consequences of impairing the ovary health and reproductive potential of fish, hence reducing the fish population.

In vivo toxicological evaluation of polymer brush engineered nanoceria: impact of brush charge

Nanoceria has a broad variety of industrial and pharmacological applications due to its antioxidant activity. Nanoceria can be modified by surface coating with polyelectrolyte brushes. Brushes can increase the surface charge of nanoceria, providing greater aqueous stability while reducing agglomeration. However, surface-coating also behaves as a barrier around nanoceria, affecting its redox equilibrium and, hence, its biological and toxicological properties. In the present study, we examined whether bare nanoceria (CeO2; 80–150 nm) and nanoceria modified by surface polymer brush, using negatively charged polyacrylic acid (CeO2@PAA) and positively charged poly (2-(methacryloyloxy)ethyl-trimethyl-ammonium chloride (CeO2@PMETAC), could induce systemic toxicity. As CeO2 has limited colloidal stability, which might result in vascular occlusion, intraperitoneal injection was used instead of intravenous administration. C57Bl/6 mice were four times injected with three different doses of each nanoceria-based sample (corresponding to 1.8, 5.3 and 16 mg Ce/kg BW/administration) for a total period of 14 days. CeO2@PMETAC induced a significant dose-dependent neutrophilia. Histopathological evaluation showed inflammatory processes in the capsule of liver, kidney, and spleen of animals at all doses of CeO2@PMETAC, and with the highest dose of CeO2@PAA and CeO2. However, none of the nanoceria-based samples tested increased the level of DNA damage or micronuclei in blood cells, even though Ce was detected by inductively coupled plasma mass spectrometry analyses in the bone marrow. Only CeO2@PMETAC induced the presence of megakaryocytes in the spleen. A higher accumulation of Ce in mononuclear phagocyte system organs (liver, spleen and bone marrow) was observed after CeO2@PMETAC treatment compared with CeO2@PAA and CeO2.

Cross‐Species Genetic Toxicity Assessment Accomplished by Flow Cytometric Analysis of Blood

The formation of micronuclei in blood cells has been an established indicator of genotoxicity for decades. Standard microscopy methods are time-consuming and lack the objectivity that fully automated methods can provide. The ability of flow cytometric technology to rapidly and objectively survey thousands of cells for micronuclei can significantly improve the value of this endpoint. In addition, since many more cells can be scored, and specific populations can be targeted, species that historically have been difficult to obtain micronucleus data from, such as humans, can now be readily evaluated using this methodology. This unit describes a procedure for fixation, staining, and analysis of blood samples using materials supplied in MicroFlow kits (Litron Laboratories) and a single-laser flow cytometer. This methodology provides a reliable, robust assessment of chromosome damage that is used in basic science research as well as drug-safety screening programs at large pharmaceutical and chemical companies.

Investigation of genotoxic effects of inhalative occupational exposure to vanadium: results of a multiple endpoint study

Animal experiments showed that inhalative exposure to vanadate causes lung cancer. To assess DNA damage in exposed workers (EW, n = 52) of a metal factory, we monitored DNA migration and formation of micronuclei in blood cells of EW, who are exposed to vanadium pentoxide via inhalation and in a matched control group (CG, n = 54). Median level of vanadium serum concentrations of EW (2.23 μg/l) was found to be 7-fold increased compared to CG (0.31 μg/l). In the standard single cell gel electrophoresis (SCGE) assay with leucocytes, no differences were detected between EW and CG, but increased levels of oxidised DNA bases (detected with FPG and ENDO III) were found (p < 0.05). Pretreatment of leukocytes with bleomycin resulted in a higher extent of DNA migration (27%, p < 0.001) and reduced capacity of DNA repair (by 42%, p < 0.001) in EW. Furthermore, the cytochalasin blocked micronucleus (CBMN) assay was carried out with peripheral lymphocytes (n = 24 per group). EW showed a 2.5-fold higher MN frequency as CG and a 7fold increase of nucleoplasmic bridges (which reflect formation of dicentric chromosomes) was seen. Nuclear buds (attributable to gene amplification events) were 3fold higher in EW (p < 0.001 for all events). Apoptosis rates did not differ significantly between the two groups, whereas necrosis rates doubled in EW (p < 0.001). Taken together, our results show increased genetic damage in individuals which inhale vanadium dust, possibly indicating increased risk for cancer.

Evidence that methanol inhalation does not induce chromosome damage in mice

Mice were exposed by inhalation to 800 or 4000 ppm methanol for 5 days, and cytogenetic effects were analyzed in blood erythrocytes, lung cells, and testicular germ cells. The results were uniformly negative; no increased frequencies of micronuclei in blood cells, of sister-chromatid exchanges, chromosome aberrations, or micronuclei in lung cells, or of synaptonemal complex damage in spermatocytes were found. From the standpoint of risk assessment, these experimental studies do not reveal any evidence of a cytogenetic hazard associated with inhalation of methanol.