Resumo

RODRIGUEZ FERREIRO, Gisell; CANCINO BADIAS, Lourdes; PRIETO GONZALEZ, Elio  e  ESPINOSA AGUIRRE, Javier. Tinidazol: una droga antimicrobiana con actividad genotóxica. Rev Cubana Invest Bioméd [online]. 2001, vol.20, n.1, pp.54-58. ISSN 0864-0300.

The reduction of the mitro group existing in various drugs, pesticides and materials of daily use gives rise to reactive oxygen species capable of interacting with DNA. Tinidazole, an antimicrobial drug of the family of the 5 nitroimidazols was tested using a comet assay. The capacity of this drug to induce single chain breaks and alkali-sensitive sites expressed as the percentages of damaged cells and cells at each level of damage was studied. The in vitro assay at concentrations of 100, 250 and 500 µ/mL showed the induction of breaks in rat leukocyte chromosomes after 30 minutes of exposure. This indicated a dosage-response ratio. The importance of the hepatic microsomal nitroreductase-mediated nitro group reduction for the mutagenic activity of nitroimidazols has been studied. However, these results revealed that tinidazole did not require to be metabolized to induce damage. After 30 minutes of repair, the leukocyte damage persisted, and 60 minutes after only the damage caused by the 500 µ/ml tinidazole concentration had been repaired. At higher concentrations, different repair mechanisms are triggered so as not to put cell viability in jeopardy. These mechanisms may be responsible for these findings; the breaks are repaired even if the fidelity of DNA sequence is endangered. It can be observed in the in vivo/assay that a dose of 100 mg/kg weight can induce damage in mouse leukocyte DNA. This effect was seen 24 and 48 hrs after the treatment with a dose that triplicated the therapeutical dose (2g/day). The suggested mechanism for explaining the clastogenic effect of the five nitrimidazols is related with the formation of a nitro annion which re-oxidizes an generates reactive oxygen species

Palavras-chave : DNA DAMAGE; TINIDAZOLE [therapeutic use]; TINIDAZOLE [toxicity]; REACTIVE OXYGEN SPECIES; INBRED BALB C.

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