Effects of in utero exposure to diisodecyl phthalate on fetal testicular cells in rats

Abstract

Diisodecyl phthalate (DIDP) is one of synthetic phthalate plasticizers. It is widely used in plastic products and is a potential endocrine disruptor. However, the effects of DIDP on fetal testicular cell development remain unclear. The objective of the present study was to determine the effects of DIDP on fetal testis development in rats after in utero exposure. Sprague Dawley dams were randomly divided into 5 groups and were daily gavaged with DIDP (0, 10, 100, 500, and 1000 mg/kg body weight) from gestational day 14–21. Serum testosterone levels, fetal Leydig cell number and distribution, testicular gene and protein expression in male pups were examined. DIDP decreased serum testosterone levels at 1000 mg/kg (1.37 ± 0.40 ng/mL, mean ± SE) when compared to the control level (3.14 ± 0.60 ng/mL). DIDP did not affect numbers of Leydig and Sertoli cells. DIDP significantly induced abnormal aggregation of fetal Leydig cells and increased the incidence of multinucleated gonocytes at 1000 mg/kg. Furthermore, DIDP down-regulated expression of Star, Cyp11a1, Hsd17b3, and Insl3 in fetal Leydig cells at 1000 mg/kg and Sox9 in Sertoli cells at 1000 mg/kg. In conclusion, the current study indicates that in utero exposure to high-dose DIDP disrupts the development of fetal testicular cells, thus affecting the male reproductive system.