Evaluation of the testicular toxicity of prenatal exposure to bisphenol A and phthalate based on microarray analysis

In the present study, the effects of prenatal exposure to bisphenol A (BPA) and diethyl hexyl phthalate (DEHP) on male reproductive system of offspring were examined by a tissue-specific microarray and gene annotation with Medical Subject Headings (MeSH) indicative of testicular components. The aim of this study was to investigate the validity of microarray analysis with MeSH as a method for obtaining and evaluating an overview of testicular toxicity mechanisms in maternally exposed specimens. Pregnant mice were treated with BPA or DEHP by subcutaneous administration on days 7 and 14 of pregnancy. Tissue and blood samples were collected from 6-week-old male offspring. Testes were subjected to gene expression analysis using quantitative RT-PCR and cDNA microarray (testis2). To interpret the microarray data, genes were classified using MeSH related to the functions of testis and sperm. As a result, MeSH categories related to androgen of dysregulated genes and Sertoli cells of downregulated genes were only enriched in BPA-treated groups. These results were consistent with the observations in the sperm properties and histological examination of testes. This article concludes that 1) microarray analysis of expression changes of genes associated with testicular function and spermatogenetic process, and 2) a method using MeSH to extract common terms among dysregulated genes, are useful for predicting an overview of the testicular and reproductive toxicity of prenatal exposure to chemical substances. RNA sample was taken from testis of 6 weeks old mouse prenatally received BPA (5 and 50 mg/kg/time) or DEHP (2 and 20 mg/kg/time), while control RNA was taken from control counterpart prenatally received corn oil alone. Direct dye-swap comparisons of sample/control were made on a pair of arrays with normalized data from Cy3/Cy5 channels for data analysis and comparison to the control data.