Toxicogenomic Assessment of Liver Responses following subchronic exposure to furan in Fischer F344 rats [miRNA]

ABSTRACT: Furan is a widely used industrial chemical and a common contaminant in heated foods. Chronic furan exposure has been shown to cause cholangiocarcinoma and hepatocellular tumors at doses of 2 mg/kg bw/day with gender differences in frequency and severity. The hepatic transcriptional alterations induced by low doses of furan (doses below those inducing liver tumors) and the potential mechanisms underlying gender differences are largely unexplored. We used DNA microarrays to examine the global hepatic mRNA and microRNA transcriptional profiles of male and female rats exposed to 0, 0.03, 0.12, 0.5 or 2 mg/kg bw/day furan over 90 days. Marked gender differences in gene expression responses to furan were observed, with many more altered genes in exposed males than females, confirming the increased sensitivity of males even at the low doses. Pathway analysis supported that key events in furan-induced hepatotoxicity in males included gene expression changes related to oxidative stress, apoptosis and inflammatory response, while pathway changes in females were consistent with primarily adaptive responses (regeneration). Pathway benchmark doses (BMDs) were estimated and compared to relevant apical endpoints. Transcriptional BMDs could be examined in males, they ranged from 0.08 – 1.43 mg/kg bw/day and approximated those derived from traditional histopathology. MiR-34a (a target of P53 signalling) was the only microRNA significantly increased at the 2 mg/kg bw/day, providing evidence in support of the importance of apoptosis and cell proliferation in furan hepatotoxicity. Overall, this study demonstrates the use of transcriptional profiling to discern mode of action and mechanisms involved in gender differences. Total RNAs from 16 liver samples (4 males and 4 females from control and 2 mg/kg bw/day dose groups) were processed using the miRNA Complete Labelling and Hybridization kit (Agilent Technologies Inc.). Labelled RNA was hybridized on 8 X 15K Agilent rat miRNA microarray slides. Arrays were scanned using an Agilent G2505B scanner (5 ?M resolution). Feature extraction (version 10.7.3.1, Agilent Tech. Inc.) was used to acquire the fluorescence intensity of each probe.

ORGANISM(S): Rattus norvegicus

SUBMITTER: hongyan dong 

PROVIDER: E-GEOD-62807 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress