Lactational exposure to environmentally relevant benzo(a)pyrene causes astrocytic activation and anxiety-like behavior in male mice

Previous studies have shown the adversely neurodevelopmental effects of exposure to benzo(a)pyrene (BaP) at early life stage. However, it is unclear the effects of lactational exposure to environmentally relevant BaP on anxiety-like behavior and the molecular mechanisms related. In this study, lactational exposure to 1 and 10 μg/kg bw BaP from postnatal day 3–21 caused anxiety-like behavior and alterations of the expressions of the neurodevelopment and anxiety-related genes in adolescence male mice using O cycle maze. Moreover, BaP exposure increased the expression level of glial fibrillary acidic protein, a typical marker of astrocytes, in hippocampus of male offspring. The release of pro-inflammatory cytokines interleukin 6 and tumor necrosis factor α was also elevated in BaP-treated offspring. Further, lactational exposure to BaP decreased the level of glutathione and the expressions of antioxidant genes (Thioredoxin 1 and Glutaredoxin 2) in male offspring. Our study demonstrated that environmentally relevant BaP lactational exposure caused anxiety-like behavior in male offspring involved in astrocytic activation, neuroinflammation, and antioxidant capability dysfunction.