Micronuclei and Nuclear Buds Induced by Cyclophosphamide in Crocodylus moreletii as Useful Biomarkers in Aquatic Environments

Abstract

Micronuclei (MN) are used to assess genotoxic exposure, whereas nuclear buds (NBs) have been linked to genotoxic events. Crocodylus moreletii was studied to identify MN and NBs. Three groups were formed: Group 1 (water) and groups 2 and 3 (7 or 10 mg/kg of cyclophosphamide). A drop of blood was obtained daily from the claw tip at 0 to 120 h. Spontaneous micronucleated erythrocytes (MNEs) and erythrocytes with nuclear buds (NBEs) were counted. The frequencies of micronucleated young erythrocytes (MNYEs) and NB young erythrocytes (NBYEs) were evaluated, including the ratio of young erythrocytes (YE)/1000 total erythrocytes. No significant differences were observed in the YE proportion on sampling days; group 1 did not show differences for any parameter, whereas group 2 showed significant differences in MNEs and NBEs, and group 3 showed differences in NBEs and NBYEs. Some mitotic activity in circulation was observed in YEs. In conclusion, NBEs could be a more sensitive biomarker to genotoxic damage than MNEs. The identification of these biomarkers leads us to propose Crocodylus moreletii as a possible environment bioindicator because these parameters could be useful to analyze the in vivo health status of these reptiles and for biomonitoring genotoxic pollutants in their habitats.

Micronúcleos: Actualización del papel en la inestabilidad genética, inflamación, envejecimiento y cáncer. Revisión panorámica.

“…Dependiendo de la especie se debe considerar la histología del bazo, ya que el sinusoidal elimina los eritrocitos micronucleados (EMN) de sangre periférica casi al 100%, como sucede en el humano; en contraste, el bazo no sinusoidal no es tan eficiente en retirar los EMN, por ello en sangre periférica se pueden observar altas frecuencias de EMN espontáneos, como en el ratón. La prueba de EMN en sangre periférica requiere de solo unas gotas de sangre, hacer dos frotis (el de trabajo y el de respaldo) el conteo es sobre 10, 000 eritrocitos totales (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16).…”