In utero exposure of high-dose di-n-butyl phthalate resulted in opposite effects on testicular cell apoptosis in late embryonic and pubertal male rat offspring

Abstract

Objective: To investigate the effects of in utero exposure to high-dose di- n-butyl phthalate (DBP) on testicular cell apoptosis in late embryonic and pubertal male rat offspring. Methods: Twenty pregnant Sprague-Dawley (SD) rats were divided into two groups. During gestation day (GD) 12 to GD 19, control group was given 1 ml day−1 of olive oil and experimental group was given DBP 500 mg kg−1 day−1 by gavage. On GD 19.5 and postnatal day (PND) 45, the testes were removed. Morphological analysis of the testes was observed by transmission electron microscopy and hematoxylin and eosin (H&E) staining. Testicular cell apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). The expression of Bcl-2, Bax, and p53 was presented by immunohistochemistry (IHC) and western blot. Data of the two groups was compared using independent samples t-test and Mann–Whitney test by SPSS 20.0. Results: H&E staining showed that spermatogenetic cells were significantly decreased in DBP exposed pubertal rat testis. The apoptosis index of testes in DBP-treated group was significantly lower on GD 19.5 but higher on PND 45 than that of the controls ( p < 0.01). IHC and western blot revealed significantly increased expression of Bcl-2 in GD 19.5 rat testis and Bax and p53 in PND 45 rat testis after DBP exposure, compared with the control ( p < 0.05). Conclusion: In utero exposure of high-dose DBP resulted in opposite effects on testicular cell apoptosis in late embryonic and pubertal rat offspring. The overexpression of Bcl-2, Bax, and p53 might be related to the occurrence of abnormal apoptosis and finally produce male infertility.