Number Of Micronuclei In Cells Research Articles

A Study on Micronuclei in Tobacco and Related Habits

Introduction: Oral cancer is one of the ten most common causes of mortality in developing countries like India. A micronucleus (MN) is a small extra nucleus separated from the main one, generated during cellular division by late chromosomes or by chromosome fragments. Micronucleus is a potential biomarker for malignancy. Aim and Objectives: The study attempts to analyze micronuclei in buccal smear from patients with tobacco and related habits; and to determine its reliability as a biomarker for carcinogenesis. Study Design: A total of 400 consisting of normal subjects, patients with potentially malignant lesions and patients with malignant lesions were included in the study. Oral exfoliated cells were collected by scrapings of buccal mucosa of both control and study groups with a tooth brush. The scrapings collected from right and left buccal mucosa of each subject were studied under two separate slides. A total of 500 cells were examined from each slide. All the micronucleus cells located on each slide were examined again under the 100X magnification. Results: The P value for intergroup difference in average number of micronuclei in cells of buccal mucosa among all groups was <0.001 which was highly significant. The P value for micronucleated cells of buccal mucosa among all groups was <0.001 which was highly significant. Conclusion: A stepwise increase in MN counts from normal to potentially malignant to carcinoma suggested a link of this biomarker with neoplastic progression. Micronuclei can be used as a biomarker for early detection of premalignant and malignant lesions of the oral cavity.

Carvacrol and rosemary oil at higher concentrations induce apoptosis in human hepatoma HepG2 cells

Natural essential oils are volatile herbal complex compounds which manifest cytotoxic effects on living cells depending on their type and concentration but usually they are not genotoxic. Our previous studies showed that carvacrol (CA) and rosemary essential oil (RO) induced growth inhibition of both human cell lines HepG2 and BHNF-1, with hepatoma HepG2 cells being more sensitive to either compound tested. Cytotoxic concentrations of CA and RO induced the formation of DNA strand breaks. Further ex vivo studies showed that extracts prepared from hepatocytes of CA- and RO-supplemented rats did not increase incision repair activity compared to extracts from liver cells of control animals. Therefore, the aim of this work was to determine the effect of cytotoxic concentrations of CA and RO on the cell cycle and the ability of both natural volatiles to induce DNA fragmentation and apoptotic death of human hepatoma HepG2 cells. These effects were measured after 24 h incubation of HepG2 cells with CA and RO using three independent methods – flow cytometry, internucleosomal DNA fragmentation (electrophoresis) and micronucleus assay. Evaluation of morphological changes and formation of micronuclei in HepG2 cells showed no increase in the number of micronuclei in cells treated by CA and RO compared to control cells. On the other hand, CA and RO induced morphological changes typical for apoptosis in concentration-dependent manner. The presence of necrosis was negligible. Both natural compounds caused shrinking of cytoplasmic membrane and formation of apoptotic bodies. In addition, the highest concentrations of CA and RO induced internucleosomal DNA fragmentation (formation of DNA ladder) in HepG2 cells. Cell cycle analysis revealed the accumulation of cells in the G1 phase, which was accompanied by a reduction in the number of cells in the S phase after 24 h exposure to the substances tested. The cell division was thus slowed down or stopped and this process resulted in cell death.

Micronucleus level in exfoliated buccal mucosa cells of cancer patients

Micronucleus levels in exfoliated buccal mucosa cells of patients with primary breast, lung, cervix uteri cancer, and patients with Hodgkin's disease were studied (n=59). Significantly increased number of micronuclei in cells of cancer patients was observed compared with healthy persons (n=45). The evaluation of micronuclei number in buccal mucosa cells shows genomic instability in somatic cells of humans.