Los felinos: ¿Una alternativa en estudios de toxicología genética?

Felines: an alternative in genetic toxicology studies? The micronuclei (MN) test carry out in peripheral blood is fast, simple, economic and it is used to detect genotoxic environmental agents. MN are fragments of chromosomes or complete chromosomes remaining in the cytoplasm after cell division, which increase when organisms are exposed to genotoxic agents. Therefore, species with the highest values of spontaneous micronucleated erythrocytes (MNE) are the most suitable to be potentials biomonitor of micronucleogenic agents, using a drop of blood. Nine species of Felines that present spontaneous MNE in peripheral blood are shown. From these species, the cat has been previously proven, with positive results and also lion (Panthera leo), yaguaroundi (Felis yagoaroundi), lynx (Lynx ruffus), jaguar (Panthera onca), puma (Puma concolor), tiger (Panthera tigris), ocelote (Felis padalis) and leopard (Panthera pardus) display spontaneous MNE, and with this characteristic this Family can be propose like a potential group to be used in toxicogenetic studies. Rev. Biol. Trop. 56 (2): 969-974. Epub 2008 June 30.

La prueba de micronúcleos (MN) en sangre periférica es rápida, sencilla, económica y sirve para detectar genotóxicos ambientales. Los MN son fragmentos de cromosomas o cromosomas completos que por alguna causa quedan fuera del núcleo en mitosis, pero que incrementan significativamente cuando los organismos que los presentan de manera espontánea se exponen a genotóxicos. Por lo tanto, el requisito para que una especie pueda ser utilizada para esta prueba es que presente eritrocitos micronucleados espontáneos (EMNe), con lo que estas especies pueden ser potenciales bioindicadores de genotóxicos micronucleogénicos, con sólo una gota de su sangre. En el presente articulo es mostramos 9 especies de felinos que como característica general presentan EMNe. Del total de especies de felinos, el gato ha sido previamente probado, con resultados positivos y ya que también el león, yaguaroundi, lince, jaguar, puma, tigre de bengala, ocelote y leopardo presentan EMNe, esta familia puede ser propuesta como un grupo potencialmente adecuado para estudios de toxicogenética. En otras palabras, cada una de estas especies puede llegar a ser un modelo potencial para determinar exposición a genotóxicos en nuestro entorno, de una manera sencilla y rápida.

[Felines: an alternative in genetic toxicology studies?]. / Los felinos: Una alternativa en estudios de toxicología genética?

The micronuclei (MN) test carry out in peripheral blood is fast, simple, economic and it is used to detect genotoxic environmental agents. MN are fragments of chromosomes or complete chromosomes remaining in the cytoplasm after cell division, which increase when organisms are exposed to genotoxic agents. Therefore, species with the highest values of spontaneous micronucleated erythrocytes (MNE) are the most suitable to be potentials biomonitor of micronucleogenic agents, using a drop of blood. Nine species of Felines that present spontaneous MNE in peripheral blood are shown. From these species, the cat has been previously proven, with positive results and also lion (Panthera leo), yaguaroundi (Felis yagoaroundi), lynx (Lynx ruffus), jaguar (Panthera onca), puma (Puma concolor), tiger (Panthera tigris), ocelote (Felis padalis) and leopard (Panthera pardus) display spontaneous MNE, and with this characteristic this Family can be propose like a potential group to be used in toxicogenetic studies.

Micronuclei in diabetes: folate supplementation diminishes micronuclei in diabetic patients but not in an animal model.

Diabetes mellitus (DM) is associated with a high risk of health complications, mainly due to excessive free radical (FRs) production that could result in an increased frequency of micronuclei. The consumption of antioxidants, like folic acid (FA), may mitigate the effects of the FRs. In the present study, micronucleated polychromatic erythrocyte (MNPCE) frequencies were determined in blood sampled weekly from the tails of pregnant female Wistar rats and pregnant Wistar rats with experimental diabetes that were given unsupplemented diets and diets supplemented with FA. At birth, the pups were sampled to analyze micronucleated erythrocyte (MNE) and MNPCE frequencies. Moreover micronucleated cells (MNCs) were evaluated in buccal mucosa samples taken from 81 healthy adult subjects, 48 patients with DM, and 30 DM patients who were sampled before and after FA treatment. Increases in MNPCE frequencies were significant only at the first sampling (P<0.01 and P<0.03) in pregnant rats with experimental diabetes. In addition, the pups from the diabetic group and from diabetic group treated with FA had higher frequencies of MNEs (P<0.03 and P<0.001, respectively) and MNPCEs (P<0.009 and P<0.05, respectively) than the controls. No differences were found in diabetic rats and newborn rats born to diabetic mothers treated with FA compared with untreated animals. Patients with DM had a higher frequency of MNCs compared with healthy subjects (P<0.001). Also FA reduced the frequency of MNCs in DM patients (P<0.001). The results of this study indicate that diabetes results in elevated frequencies of micronuclei, and that, at least in humans, FA can protect against the elevation.

Induction of micronucleated cells in the shed skin of salamanders (Ambystoma sp.) treated with colchicine or cyclophosphamide.

The micronucleus (MN) assay can be used to detect the genotoxic effects of chemical agents in virtually any cell that divides frequently. Salamanders (Ambystoma sp.) are amphibians that can be easily maintained and bred in the laboratory and spontaneously shed their skin every 2.5-4 days. In this present study, we have evaluated the usefulness of this shed skin for the MN assay. We exposed salamanders to different concentrations of both the aneugen colchicine (COL) and the clastogen cyclophosphamide (CP) and we determined the frequency of micronucleated cells (MNCs) in their sheds. Fragments of shed skin were placed on clean slides, fixed, stained, observed with a light microscope, and the number of MNCs was counted. The MNC frequency was increased significantly by all doses of COL and CP tested, administered either as single or repeated exposures. The presence of MNCs in the shed skin and the speed of sloughing lead us to propose that the sheds of Ambystoma sp., or other amphibians that slough their skin, are suitable alternative models for detecting genotoxic exposures relevant to aquatic environments.