Abstract
Di-(2-ethylhexyl) phthalate (DEHP) has been shown to induce mammal hypospadias, in which the molecular etiology of the defect is poorly characterized. Because activating transcription factor 3 (ATF3) is upregulated in tissues of patients or mice with hypospadias, it has been conjectured that ATF3 might play a key role in the etiology of hypospadias. Accordingly, it has become a focus of research. We previously established a mouse model of hypospadias with DEHP, and hypothesized that ATF3 might be involved in its pathogenesis. In this developmental toxicity study, pregnant C57BL/6 mice were exposed to corn oil or DEHP (100 or 500 mg/kg/day) from embryonic day 12 (ED12) to ED16. Apoptosis was characterized by Terminal transferase dUTP nick end labeling (TUNEL) assay. Using RT-PCR and western blot, the expressions of ATF3 and apoptosis-related genes (P53, Bcl-2 and Bax) were investigated. Apoptosis of fetal mouse genital tubercle (GT) cells notably decreased after DEHP treatment. DEHP activated ATF3 both at the mRNA and protein levels in GT. Furthermore, pro-apoptotic P53 was downregulated and the ratio of anti-apoptotic (Bcl-2)/pro-apoptotic (Bax) was not significantly changed. These results suggest that DEHP may induce external genital defects via a mechanism involving apoptosis, which might correlate with the regulation of ATF3 and P53 expressions.
