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Genotoxic evaluation of ornidazole and secnidazole in albino mice: an experimental study

Background The present study was planned to explore the genotoxic potential of some commonly used antimicrobials like ornidazole and secnidazole in swiss albino mice.

Methods Therapeutic equivalent doses of ornidazole and secnidazole were given by intra peritoneal route. Single dose in individual groups of mice (n=5 in each) was administered for acute study. Doses were repeated every 24 hrs for 7 times in additional groups of mice (n=5 in each) for sub-acute study. Cyclophosphamide served as positive control while normal saline as negative control. After 24 hrs of single dose (acute study) and last dose of drug administration in sub-acute study, about 0.5 ml of blood was collected by retro orbital sinus for comet assay as described earlier (Rojas E et al, 1999) and later the mice were sacrificed to aspirate the femoral bone marrow for micronucleus test as described earlier by described by Schmid W (1975). In comet assay, the total comet length and head diameter was measured under microscope using ocular & stage micrometer to calculate comet tail length. In micronucleus assay, the stained bone marrow tissue smears were scored for the frequency of micronucleated polychromatic erythrocytes (MnPCE) and also the ratio between polychromatic erythrocytes (PCE) to normochromic erythrocytes (NCE) was obtained.

Results It was analyzed by one-way ANOVA followed by Dunnet’s multiple comparison tests. Significant (P< 0.01) increase in comet tail length and percentage of micronucleated polychromatic erythrocytes (% MnPCE) was observed in groups treated with single and multiple doses of Cyclophosphamide whereas ornidazole and secnidazole treated groups did not show any significant changes.

Conclusions The results indicate that Ornidazole and secnidazole are devoid of genotoxicity.