RESUMO
Tons of sludge is produced daily in sewage treatment plants of large cities, causing an enormous disposal problem. Because recycling has been proposed to mitigate the situation, the potential adverse health effects of the sludge should be verified before that policy is undertaken. The present study is a part of an assessment of oral toxicity in rats fed with sewer-treated sludge and aimed to contribute to its genotoxicity characterization. After a 2-week acclimatization period, male and female Wistar rats were fed ad libitum for 90 days a pelleted commercial diet containing 0, 5000, 10,000 and 50,000 ppm of a treated sludge sample. The potential mutagenic or genotoxic effect was detected in recent animal cells by the bone marrow micronucleus test and the comet assay, respectively. For the comet assay peripheral blood samples were obtained immediately before the sacrifice from the periorbital plexus. Following sacrifices, polychromatic erythrocytes (PCEs) were analyzed in femoral bone marrow smears and the frequencies of micronucleated polychromatic erythrocytes (MNPCEs) were registered. Results of both assays indicated that exposure to any of the sludge concentrations tested did not increase the frequency of MNPCEs or the levels of DNA damage when compared to non-exposed concurrent control rats.
Assuntos
Dano ao DNA/efeitos dos fármacos , Resíduos Industriais/efeitos adversos , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Mutagênicos/toxicidade , Esgotos/química , Animais , Antimutagênicos/farmacologia , Medula Óssea/efeitos da radiação , Dano ao DNA/genética , Eritrócitos Anormais , Feminino , Raios gama , Masculino , Micronúcleos com Defeito Cromossômico/estatística & dados numéricos , Testes de Mutagenicidade , Ratos , Ratos Wistar , Eliminação de ResíduosRESUMO
OBJECTIVE: In the current study, the potential DNA damage associated with exposure to a number of antimicrobial endodontic compounds was assessed by the single cell gel (comet) assay in vitro. STUDY DESIGN: Chinese hamster ovary (CHO) cells were exposed to formocresol, paramonochlorophenol, calcium hydroxide, or chlorhexidine at final concentration ranging from 0.01% to 1%. RESULTS: Formocresol, paramonochlorophenol, and calcium hydroxide, as well as chlorhexidine in all concentrations tested did not contribute to the DNA damage. CONCLUSION: These findings are clinically relevant since they represent an important contribution to the correct evaluation of the potential health risk associated with exposure to dental agents.
