Coelomocyte biomarkers in the earthworm Eisenia fetida exposed to 2,4,6-trinitrotoluene (TNT).

FUCHS JULIO S.; PIOLA, LUCAS; PRIETO GONZALEZ, ELIO; ONETO, MARIA L.; BASACK SILVANA B.; KESTEN EVA M.; CASABÉ NORMA B.

ENVIRONMENTAL MONITORING AND ASSESSMENT

SPRINGER

Año: 2011 vol. 175 p. 127 - 137

0167-6369

Contamination by 2,4,6-trinitrotoluene (TNT) is a global environmental problem at sites of former explosive production, handling or storage, and could have deleterious consequences for human and ecological health. We investigated its sublethal effects to Eisenia fetida, using two non specific biomarkers. In coelomocytes of earthworms exposed 24, 48 or 72 h, we evaluated DNA damage (comet assay) and neutral red retention time (NRRT), using the filter paper contact test. Both percentage of damage (D%) and calculated damage index (DI) showed significant DNA damage at almost all concentrations, at all time points assayed. Along exposure time, two different patterns were observed. At the lower TNT concentrations (0.25-0.5 ug/cm2) an increased DNA migration at 48 h, with a decrease close to initial levels after 72 h exposure was observed. This decrease could be attributed to activation of the DNA repair system. At the higher concentrations (1.0-2.0 ug/cm2), the high DNA damage observed remained constant during the 72 h exposure, suggesting that the rate of DNA repair was not enough to compensate such damage. Analysis of NRRT results showed a significant interaction between time and treatment. After 48 h, a significant decrease was observed at 4.0 ug/cm2. After 72 h NRRT presented a concentration-dependent decrease, significantly different with respect to control at 0.5, 1.0, 2.0 and 4.0 ug/cm2. The two assayed methods, performed on the same sample, showed clear responses to sublethal TNT exposure in Eisenia fetida, providing sensitive unspecific biomarkers of cell injury and DNA damage.