Cytogenetic effects of the antichagasic benznidazole on human cells in vitro

Benznidazole (bz) is a widely used trypanosomicidal agent in South America. Two test systems were used to evaluate its genotoxicity in human cells in vitro: (a) human blood lymphocytes from healthy volunteers for induction of sister-chromatid exchanges (SCEs) and chromosomal aberrations (CAs); (b) a human hepatoma cell line (Hep G2) for the induction of SCEs and micronuclei (MN). In spite of being non-clastogenic on human lymphocytes, there was a significant increase in the frequency of MN on hepatoma cells treated with different doses of bz. This results support previous data which indicated the necessity of nitroreduction of nitroimidazoles to observe their mutagenic effects. Interestingly, bz induced a significant increase in the frequency of SCEs in both test systems. The sensitivity of the parameters used and the role of cellular metabolic pathways are discussed.