Genotoxicity studies on the removal of a direct textile dye by a fungal strain, in vivo, using micronucleus and RAPD-PCR techniques on male rats.

The genotoxicity of the azo dye 'Direct Violet' and the removal of this dye by Aspergillus niger strain at different conditions have been investigated in male rats. Two genotoxicity techniques, namely bone marrow micronucleus assay and RAPD fingerprinting pattern, were used in this study for the direct dye and its removal by the fungal strain. Sixty male rats were divided into six treatment groups including a control group and other groups which were exposed for 2 or 8 weeks to Direct Violet dye, Direct Violet dye treated with A. niger at pH 2 or pH 9 or without agitation and acrylamide (30 mg/kg b.w.). A potent dose-dependent response was observed following oral gavage of the dye up to 1000 mg kg(-1), after which significant toxicity to the erythroid compartment was observed. Acrylamide and Direct Violet treatments increased the number of micronucleated polychromatic erythrocytes (MnPCEs) with respect to the controls. This increase was statistically significant in the two time intervals (2 and 8 weeks treatment, P < 0.0001). Fungi treatments at pH 2 and without agitation were able to reduce the number of MnPCEs induced by Direct Violet administration in all duration groups. Fungi treatment at pH 9 was only able to inhibit the genotoxicity of Direct Violet after 8 weeks treatment. The RAPD fingerprinting pattern indicated that most DNA of the samples treated with dye alone or acrylamide revealed polymorphic bands including the appearance and disappearance of the bands, which did not appear in the DNA samples of normal or fungi protected rats. The implications of these findings for the health and safety of occupationally exposed workers are discussed.