The current study was undertaken to explain the cytogenetic and genotoxic effects of penconazole
(PEN) fungicide and chlorpyrifos (CPF) insecticide in male rats. Rats (n=10/group) were treated with
500 mg/kg body weight PEN orally for 24 h, 48 h and 100 mg/kg body weight for 30 days and the control
animals were administered distilled water only. Chlorpyrifos exposed groups received 39 mg/kg
body weight for 24 h and 48 h and 8 mg/kg body weight for 30 days by oral gavage and the control
group was received corn oil. Blood samples were collected for complete blood count. Bone marrow
was flushed from the femur bones for chromosomal aberration (CA) and comet assay. Spleen samples
were preserved in 10% formalin for histopathological examination. The level of DNA damage was measured
using DNA damage index. The results showed that PEN and CPF caused significant hematological
changes, significant increase in DNA damage index and increased the number of nuclei with I, II, III and
IV degrees of damage. Different types of CA were recorded in PEN and CPF exposed groups including
chromosomal break, deletion, attenuation, chromosome ring, gap and fragments. In addition, numerical
aberration as polyploidy appeared in CPF exposed groups only. PEN and CPF caused histopathological
changes in spleen in the form of apoptosis, congestion, thrombosis and hemosiderosis. In conclusion,
PEN and CPF induced genotoxic and cytogenetic effects in bone marrow. DNA damage index and the
percentage of CA were higher in CPF than PEN groups.