Prenatal developmental effects of pure 2,4-dichlorophe-noxyacetic acid (2,4-D) on the rat

ABSTRACT 2,4-Dichlorophenoxyacetic acid (2,4-D) a plant growth regulator, has been used worldwide as an herbicide. The phenoxyacetic acid herbicides contain both 2,4-D and 2,4,5-Trichlorophenoxyacetic acid (2,4,5-T) along with emulsifiers, solvents and contaminants; these have been recognized as teratogen in the rat and mouse. Although the high teratogenicity of phenoxyacetic herbicides has been attributed to the 2,4,5-T and the contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the possibility that 2,4-D might play a role has not been clearly ruled out We designed this study to evaluate the effects of pure 2,4-D, and herein describe the precise fetal visceral malformations. We randomly distributed pregnant Wistar rats in to three main groups according to organogenesis during which pure 2,4-D was administered at different doses: l)-over all organogenesis (gestational days 6 to 15), 2)-early organogenesis (gestational days 6 to 10), and 3)-late organogenesis (gestational days 11 to 15). We found that the pure 2,4-D is maternally toxic and has a dose-related embryolethality. The visceral malformations induced in the fetuses included ureteric dilatations and hydronephrosis, as reported, in conjunction with the herbicide forms. In addition, we observed an association with renal and urogenital aplasia, which were observed in the early organogenesis period. We performed a histopatho-logical examination and discussed the mechanism of the pathological processes. We conclude that the pure 2,4-D itself is maternally toxic and embryolethal, and potential inducer of kidney and urogenital malformations in the rat. The types of kidney and urogenital malformations seen indicated that the 2,4-D interferes in the early developmental stage of the urogenital system.