RESUMO
The aim of the study was to assess genotoxicity of a chromium(III) propionate complex in rat's peripheral blood lymphocytes by the comet assay. The study was carried out on 18 12-weeks old female Wistar rats that were divided into three equal groups (six animals each): control (0), control-Cr(VI) and Cr(III)-tested rat fed ad libitum a basal diet and the diet supplemented either with 10 mg Cr(VI)/kg diet (given as K(2)Cr(2)O(7), equivalent of 1mg/kg body mass/day) or 1000 mg Cr(III)/kg diet (given as [Cr(3)O(O(2)CCH(2)CH(3))6(H(2)O)(3)]NO(3)), equivalent of 100mg Cr/kg body mass/day) for 4 weeks. High doses of supplementary Cr(III) were found to not affect body mass gain, feeding efficiency ratio and internal organ masses. Treatment of rats with the Cr(III) propionate complex, in contrast to Cr(VI), did not affect significantly the comet assay results in lymphocytes, which suggests that the compound does not exert genotoxic effects in rats.
Assuntos
Mutagênicos , Propionatos/toxicidade , Animais , Peso Corporal/efeitos dos fármacos , Cromo/química , Cromo/metabolismo , Ensaio Cometa , DNA/efeitos dos fármacos , DNA/genética , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Processamento de Imagem Assistida por Computador , Técnicas In Vitro , Linfócitos/efeitos dos fármacos , Microscopia de Fluorescência , Tamanho do Órgão/efeitos dos fármacos , Ratos , Ratos Wistar , Aumento de Peso/efeitos dos fármacosRESUMO
The occurrence of second primary tumors after curative treatment or simultaneous multiple malignancies are current problem in head and neck cancer. The mutagen sensitivity is well known marker to predict patient proneness to develop the second tumor. The frequency and localization of spontaneous and mutagen induced chromatid breaks in peripheral blood lymphocytes (PBLs) in patients with multiple primary tumors (MPT) may help in defining regions involved in cancerogenesis process. The case control study using the bleomycin sensitivity assay (number of chromatid breaks per cell (b/c) was performed in 36 patients with MPT and two control groups: 52 patients with one malignancy and 47 healthy individuals. The differences between examined patients and control groups were estimated using U Mann-Whitney test. The b/c level in PBLs of patients with MPT ranged from 0.26 to 4.12 (mean 1.53) and was significantly higher (p<0.000006) both compared with patients with one malignancy (b/c ranged from 0.02 to 3.08; mean 0.74) and healthy controls (b/c ranged from 0.04 to 1.14; mean 0.41). An increase of b/c index was observed in almost all chromosomal arms. The majority of chromosomal locations with the increased proportion of breaks in the group of patients with multiple tumors were identified as regions where loci involved in DNA repair, cell cycle regulation suppressor genes and oncogenes were found. Statistically higher induced individual susceptibility in MPT patients compared with single tumor and healthy controls was confirmed. Comparable induced mean b/c was found in patients with two smoking-related cancers as well as with not smoking related tumors.