Embryonic exposure to dimethoate and/or deltamethrin impairs sexual development and programs reproductive success in adult male offspring mice

Summary Pesticides can be toxic to desirable plants and animals, including humans. The aim of this study was to investigate the reproductive effects of low doses of pesticides on male offspring of exposed pregnant mice. Three groups of five female mice were treated daily by oral gavage with dimethoate (5 mg kg−1 per day), deltamethrin (5 mg kg−1 per day) and their mixture at 5 mg kg−1 per day from day 3 to day 21 of pregnancy. Fertility, sexual behaviour and a number of reproductive endpoints, such as organ weights, sperm evaluations and testicular histology, were examined on four adult male offspring of exposed pregnant mice. When compared with control, a dose of deltamethrin 5 mg kg j−1 causes a decrease in the absolute and relative weight of the testes of exposed mice and it affects their fertility by reducing the density, mobility and vitality of sperm and increasing the number of abnormal forms of these cells (P ≤ 0.01). The same results were obtained in mice exposed to a dose of 5 mg kg j−1 combination of dimethoate and deltamethrin. This study demonstrated that deltamethrin and combination of dimethoate and deltamethrin caused a decrease in the absolute and relative weight of the testes, which affected the sperm parameters of male offspring of exposed mice to a low dose of these pesticides during pregnancy.