Expression of microRNAs, CYP1A1 and CYP2B1 in the livers and ovaries of female rats treated with DDT and PAHs

In this study, we determined the expression level of miRNAs and the induction of CYP1A1 and CYP2B1 in the livers and ovaries of female Wistar rats treated with DDT, benzo[a]pyrene (BP), and 3-methylcholanthrene (MC). This study compared CYP1A/2B induction and miRNA expression levels to cast light on a possible role of miRNA in the tissue-specific induction of CYPs. The induction of CYP1A1/2B1 enzymes was detected by ethoxy-, pentoxyresorufin O-dealkylation and Western blot analysis. The CYP1A1/2B1 gene expression was determined by RT—real time PCR. Relative levels of expression for selected in silico miR species were determined by real time PCR with small nuclear U6 RNA employed as a reference gene. After bioinformatic analysis, miR-21, 221, 222, and 429 were chosen as potential post-transcriptional regulators of rat CYP1A and CYP2B. It was shown that miR-21, 221, 222, and 429 expression levels decreased in the liver of DDT-, BP-, and MC-treated rats, whereas increases were observed in CYP1A1 and CYP2B1 mRNA expression levels and protein content, and EROD and PROD activities. Conversely, a tendency for elevated levels of miRNAs in the ovaries of inducer-treated female rats was observed. In the ovaries, a high level of CYP1A1 and CYP2B1 mRNA expression was observed, although protein content and enzyme activity were not visible. These data suggest a potential involvement of miRNA in the post-transcriptional regulation of CYP1A and CYP2B in the livers and ovaries of chemically induced rats.