Identification of Competing Endogenous RNA and Micro-RNA Profiles and Regulatory Networks in 4-Nonylphenol-induced Impairment of Sertoli Cells

The xenoestrogens nonylphenols (NPs), which are materials used in the plastic polymer industry, are considered endocrine disruptors in a wide range of organisms. Studies have shown that human health problems, such as infertility and reproductive toxicology, are linked with NPs. However, the mechanism by which NPs interfere with male reproduction is not fully elucidated. Here, we found that 4-NP can result in male reproductive impairment and reduce androgen receptor (AR) protein levels in rat sertoli cells in vitro and in vivo. Moreover, we performed RNA sequencing to assess the differential expression of ceRNAs in rat primary sertoli cells treated with 4-NP. Bioinformatics methods, such as Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) database and ceRNA functional network analyses, were used to investigate the sequencing data and gain further understanding of the biological processes. Our analysis revealed a core set of mRNAs (Ar, Atf6 and Cbp), and circRNAs (circ673, circ1377, circ1789, and circPTEN) that were selected and validated by RT-qPCR. In addition, the head-to-tail splicing of circ673, circ1377, circ1789, and circPTEN was identified by Sanger sequencing. These findings provide the first insight into the ceRNA expression profiles of rat sertoli cells and reveal that ceRNAs participate in 4-NP-induced impairment of sertoli cell function, thereby indicating potential therapies for both reproductive toxicology and male infertility.

Effect of Feeding Hay on Nonesterified Fatty Acids in Appetite-Suppressed Pregnant New Zealand White Rabbits

Pregnant rabbits are a common nonrodent model for reproductive safety evaluation in preclinical drug development. During reproductive toxicology studies, rabbits are prone to decreased food consumption and anorexia. When persistent or severe, this condition can lead to hepatic lipidosis and pregnancy toxemia, which may confound the interpretation of study results. Non-Esterified Fatty Acids (NEFAs) have been used in veterinary production medicine to evaluate the impact of diet on the energy balance of pregnant animals. In the current study, sustained-release buprenorphine was used to suppress the appetite of pregnant New Zealand white rabbits, mimicking the clinical presentation of animals in reproductive toxicology studies. Sequential NEFA evaluations during gestation, along with other clinical endpoints, such as the necessity and duration of veterinary intervention, were used to evaluate the effects of feeding hay and a pelleted diet as compared with a pelleted diet alone. Elevated NEFA levels were directly correlated to litter size, the number of viable fetuses and the number of days on veterinary consult due to severely decreased consumption of pelleted diet. Animals with hay as part of their diet did not require additional diet supplementation as determined by qualitative evaluation of hay intake and adequate fecal output. These data suggest that including hay as a portion of the standard diet benefits pregnant rabbits in laboratory or production settings.