OBJECTIVETo study the gene expression patterns in livers of infant rats after Benzo[a]pyrene (BaP) exposure during pregnancy and explore the important gene and signaling pathways in the toxic mechanism of BaP.

METHODSThirty-two pregnant SD rats were randomly divided into four groups: vehicle control (corn oil) and treatment groups (0.75, 1.50 and 3.00 mg/kg BaP in corn oil). BaP solutions were given by gastric infusion from the 3rd to the 17th day of pregnancy. After delivery the offspring's liver were taken to detect the gene expression by RatRef-12 gene chip. The stability of gene chip was tested by repeated experiments.

RESULTSAfter prenatal BaP exposure 1232 genes with different expression variations in hepatocytes of offsprings were identified. Three expression patterns of genes related to the dose of prenatal BaP exposure were identified with significant difference (P < 0.05). As the dose of prenatal BaP exposure increased, the gene expression patterns were downregulated, upregulated, and fluctuated. Twenty-six signaling pathways with differently expressed genes mainly focused on: growth and development, toxicant metabolism and inflammation (P < 0.05). The data from gene network analysis demonstrated that CYP2C13, GSTO1, Rela, MAPK8 and Plcg1 were the key genes in the gene network.

CONCLUSIONGene expression patterns of offsprings' hepatocytes were influenced by prenatal BaP exposure. Some key genes and signal pathways were also found. The study provides an important clue for the toxicity and mechanisms of the prenatal BaP exposure on the growth and development of offspring.