ORIGINAL ARTICLE Embryonic exposure to dimethoate and/or deltamethrin impairs sexual development and programs reproductive success in adult male offspring mice A. Ben Slima 1 , F. Ben Abdallah 2 , L. Keskes-Ammar 3 , Z. Mallek 4 , A. El Feki 5 & R. Gdoura 1 1 Laboratory of Microbiology, Unit Research 08-73, Faculty of Sciences of Sfax, University of Sfax, Sfax, Tunisia; 2 Human Pathologies and Oxidative Stress Unit, Superior Institute of Biotechnology of Sfax, Sfax, Tunisia; 3 Laboratory of Histology Embryology and Reproductive Biology, Medicine Faculty of Sfax, Sfax, Tunisia; 4 Veterinary Research Centre of Sfax, Sfax, Tunisia; 5 Laboratory of Animal Ecophysiology, Faculty of Sciences, University of Sfax, Sfax, Tunisia Introduction A number of chemicals such as pesticides are known to interfere with the endocrine system and thereby impair fertility and the development of animals and possibly of humans (Figa-Talamanca et al., 2001). Pyrethroids (PYR) are the major class of insecticides used in the USA. Rodriguez et al. (2009) demonstrated that cypermethrin, a synthetic pyrethroid, has been impli- cated in the development of a variety of reproductive dis- orders in humans and infertility in wildlife, where it increases the death rate of the offspring and induces aggressiveness. Deltamethrin (DLM) is a a-cyano-containing synthetic pyrethroid type II, used on a worldwide scale. It belongs to the group of pyrethroids classified by the World Health Organization as moderately harmful, class II (World Healh Organization, 1995). DLM has a deleteri- ous effect of on male fertility (Abd El-Aziz et al., 1994; El-Gohary et al., 1999). The possibility of disturbances induced during the prenatal or early post-natal period has attracted special attention (Alm et al., 1996; Williams et al., 2001). Although the major site of action of delta- methrin seems to be the voltage-dependent sodium chan- nel, additional target sites are also involved in the toxic action of type II pyrethroids (Forshaw et al., 2000). These Keywords Deltamehtrin—dimethoate—male offspring mice—pregnancy—reproductive effects Correspondence Radhouane Gdoura, Faculte ´ des Sciences de Sfax, Rue de Soukra Km 3, 5, BP 1171, 3000 Sfax, Tunisie. Tel.: +216 98973864; Fax: +216 74274437; E-mail: gdourar@yahoo.com Accepted: September 2, 2011 doi: 10.1111/j.1439-0272.2011.01246.x 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 num- ber 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 demon- strated 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. ª 2011 Blackwell Verlag GmbH Andrologia 2012, 44, 661–666 661