Cytogenetic evaluation of malathion-induced toxicity in Sprague-Dawley rats

► We study the genotoxic effects of malathion on Sprague-Dawley rats. ► We examine its effects on mitotic index and chromosome structure in bone-marrow cells, and on DNA integrity in leukocytes. ► Malathion exposure significantly decreases the mitotic index. ► On the other hand, it significantly increases the frequency of structural chromosomal aberrations (SCA) and the percentage of DNA damage, in a dose-dependent manner. ► Malathion has a strong clastogenic/genotoxic potential as measured by the SCA and Comet assays.