Mouse and human micronucleus models for assessing genotoxicity of whole foods in intervention studies

The relationship of micronucleus frequency and nuclear division index with coronary artery disease SYNTAX and Gensini scores

Objective:

We aimed to evaluate the relationship of micronucleus (MN) frequency and nuclear division index (NDI) with SYNTAX and Gensini scores and thrombolysis in myocardial infarction (TIMI) frame counts of coronary arteries in patients undergoing coronary angiography.

Methods:

In a single-center prospective observational study, a total of 63 individuals, 48 consecutive patients with coronary artery disease (CAD) and 15 healthy people were included. Before coronary angiography (exposure to X-ray), blood samples were collected for lymphocyte cultures, MN and NDI measurements. According to the SYNTAX and Gensini scores, patients were allocated into two groups. Group 1 and 2 included the patients with SYNTAX scores <22 and ≥22 points, respectively. Similarly, groups according to Gensini scores included the ones <23 and ≥23 points. MN test was used for in vitro studies in human peripheral lymphocytes. Binucleated lymphocytes were calculated for each patient.

Results:

MN frequency was significantly higher in group 2 than group 1 and in group 1 than control group (p<0.001). NDI was significantly higher in control group than group 1 and in group 1 than group 2 (p=0.003). MN frequency had positive but moderate correlation with SYNTAX and Gensini scores and TFCs of left anterior descending (LAD), circumflex and right coronary arteries (r=0.394, p=0.003; r=0.458, p<0.001; r=0.425, p<0.001; r=0.469, p<0.001; and r=0.475, p<0.001, respectively).

Conclusion:

We can conclude that as the degree of atherosclerosis increases and coronary flow worsens, MN frequency increases and NDI decreases. Our results may help to elucidate the relationship of DNA damage in pathophysiology of atherosclerosis and endothelial dysfunction in patients with stable CAD.

Mitogenic potential inducible by He:Ne laser in human lymphocytes in vitro

The objective of the study was to investigate the mitogenic and genotoxic effects of He:Ne laser irradiation (632.8 nm) on human peripheral lymphocytes in vitro. We used the cytokinesis-block micronucleus assay, which incorporates cytochalasin B to inhibit cytokinesis while karyokinesis proceeds normally leading to the appearance of proliferating lymphocytes as binucleated cells. Also micronuclei will appear in cases of genotoxicologically-affected cells. Buffy coat leukocytes were exposed to 10 mW He:Ne laser at energy densities of 1, 2, 3 and 5 J/cm(2). Cells were then cultured in media 199 without any supplementation for 24, 48, 72 and 96 h adding cytochalasin B 24 h before harvesting of cells. Our results showed that laser-induced lymphocytes proliferate throughout the four consecutive days post-laser irradiation. The difference in the frequency of micronuclei between pre- and post-laser irradiation indicates that a He:Ne laser at such energy densities 1, 2, 3 and 5 J/cm(2) does not induce micronucleus formation. These results shed some light on the mechanism encountered by lymphocytes in the process of He:Ne laser-induced biostimulation.

Micronucleus frequency in spleen lymphocytes from severely malnourished rats during lactation

The purpose of this ex vivo study was to determine if severe malnutrition increases the frequency of micronuclei in spleen lymphocytes of experimentally malnourished rats during lactation. Micronucleus frequencies were analyzed in binucleate cells produced by the cytokinesis block method. The overall micronucleus frequency was significantly higher in binucleate cells from malnourished rats (21.30/1000) as compared to that observed in control rats (11.50/1000). The number of binucleate cells with more than one micronucleus was also higher in malnourished rats than in controls (3.10/1000 vs. 1.20/1000). These results indicate that severe malnutrition produces cellular damage in vivo, as was evidenced by the increased micronucleus frequency in rat spleen lymphocytes in vitro. This damage may produce negative effects for the further development of the organism, since the spleen is an important lymphopoietic organ in rodents.