Identification of Rat foreskin biomarkers of in utero dibutyl phthalate exposure [Illumina]

Dibutyl phthalate was administered to pregnant Sprague Dawley rats from gestational days 16-20 at either a 100 mg/kg/day or 500 mg/kg/day dose level. This timeframe covers the reproductive masculinization window which corresponds to increased androgen signalling. Dibutyl phthalate has been shown to disrupt testosterone production leading to male reproductive abnormalities. As such, we selected this exposure window for our study and examined gene expression changes in the male rat foreskin, which expresses the androgen receptor. We collected tissue samples at both gestational day 20 to identify gene expression changes immediately after exposure, and postnatal day 5 to identify gene expression changes persisting after birth using microarray analysis (Illumina RatRef 12 Bead Chips). To determine whether gene expression changes were brought on by decreased androgen signalling or additional effects of dibutyl phthalate exposure, we exposed rats to the potent androgen receptor antagonist flutamide (5 mg/kg/day) during the same period of development. Gene expression changes were compared to determine which were brought on by disruption of androgen signalling and which were the result of other aspects of chemical exposure.本研究对妊娠斯普拉格-道利大鼠（Sprague Dawley rats）于妊娠第16至20天给予邻苯二甲酸二丁酯（Dibutyl phthalate）暴露，给药剂量分别为100 mg/kg/天与500 mg/kg/天。该时段覆盖生殖雄性化窗口期，此阶段对应雄激素信号通路（androgen signalling）增强的时期。邻苯二甲酸二丁酯已被证实可干扰睾酮（testosterone）合成，进而引发雄性生殖系统异常。因此本研究选取该暴露窗口期开展实验，并对表达雄激素受体（androgen receptor）的雄性大鼠包皮组织进行基因表达变化分析。本研究分别于妊娠第20天采集组织样本，以明确暴露后即刻的基因表达变化；于出生后第5天采集样本，以明确出生后仍持续存在的基因表达变化，实验采用微阵列分析（microarray analysis，Illumina RatRef 12 Bead Chips）完成检测。为明确基因表达变化是由雄激素信号通路减弱所致，还是邻苯二甲酸二丁酯暴露的其他效应引发，本研究在相同的发育窗口期给予大鼠强效雄激素受体拮抗剂（androgen receptor antagonist）氟他胺（flutamide）处理，给药剂量为5 mg/kg/天。后续通过对比各组基因表达变化，明确哪些变化由雄激素信号通路紊乱介导，哪些源于该化学物质暴露的其他作用。