Neonatal exposure to benzo[ a ]pyrene decreases the levels of serum testosterone and histone H3K14 acetylation of the StAR promoter in the testes of SD rats

• Published in: Toxicology (Amsterdam) Vol. 302; no. 2-3; pp. 285 - 291
• Main Authors: Liang, Jiren, Zhu, Hongyan, Li, Cuizhen, Ding, Yicheng, Zhou, Zhijun, Wu, Qing
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ireland Ltd 16-12-2012; Elsevier
• Subjects: Acetylation; adulthood; adults; Animals; Animals, Newborn; Benzo(a)pyrene - toxicity; Benzo[a]pyrene; Biological and medical sciences; blood serum; Body Weight - drug effects; Cholesterol Side-Chain Cleavage Enzyme - genetics; Cholesterol Side-Chain Cleavage Enzyme - metabolism; corn oil; Cytochrome P-450 CYP1A1 - genetics; Cytochrome P-450 CYP1A1 - metabolism; Emergency; epididymis; Epigenesis, Genetic - physiology; epigenetics; Female; gene expression; H3K14 acetylation; histones; Histones - genetics; Histones - metabolism; liver; Liver - drug effects; Liver - metabolism; Male; Medical sciences; messenger RNA; Neonatal exposure; neonates; Organ Size - drug effects; Phosphoproteins - genetics; Phosphoproteins - metabolism; promoter regions; Promoter Regions, Genetic; Rats; Rats, Sprague-Dawley; RNA, Messenger - genetics; RNA, Messenger - metabolism; Serum testosterone; spermatozoa; Spermatozoa - drug effects; Spermatozoa - metabolism; StAR; Steroid 17-alpha-Hydroxylase - genetics; Steroid 17-alpha-Hydroxylase - metabolism; testes; Testis; Testis - drug effects; Testis - metabolism; testosterone; Testosterone - blood; Toxicology; H3K14 acetylation; Testis; Benzo[ a]pyrene; Neonatal exposure; StAR; Serum testosterone; Benzo[a]pyrene; Biological fluid; Neonatal; Rat; Testicle; Promoter; Serum; Testicular hormone; Acetylation; Histone; Human; Androgen; Rodentia; Exposure; Male genital system; Testosterone; Vertebrata; Mammalia; Newborn; Decrease; Animal; Sex steroid hormone
• ISSN: 0300-483X; 1879-3185
• DOI: 10.1016/j.tox.2012.08.010

Although benzo[a]pyrene (BaP) is an environmental endocrine disrupter, it has been unclear whether neonatal exposure to BaP affects the testosterone level and, if so, whether this influence persists into adulthood. In this present study, we gave neonatal rats (through oral gavages) doses of 0, 5, 10, or 25mg/kgday of BaP in corn oil from postnatal day 1 (PND 1) to PND 7. The rats were sacrificed at PND 8, PND 35, and PND 90. BaP exposure was confirmed through the induction of liver and testis CYP1A1 mRNA expression at PND 8 (i.e., immediately after exposure). The testicular daily sperm production and the sperm counts of the epididymis cauda at PND 90 were significantly lower than those of the control. The serum testosterone levels decreased markedly at PND 8, PND 35, and PND 90 after neonatal BaP exposure relative to those of the control. The mRNA expressions of StAR also decreased relative to those of the control at PND 8, PND 35, and PND 90, although the mRNA expressions of P450c17 and 17β-HSD were suppressed significantly only at PND 8. To further elucidate the mechanism of the persistent decrease in the mRNA expression of StAR, we determined the histone acetylation level in the StAR promoter. The extent of acetylation of H3K14 in the determined region decreased after neonatal exposure to BaP; this phenomenon persisted to the adult stage. Our results indicate that neonatal exposure to BaP damages testosterone production and sperm counts in the long term, possibly as a result of epigenetic regulation in the StAR promoter region.