Developmental stage-specific changes in immunological biomarkers in male C3H/HeN mice after early life toluene exposure.

We investigated the effects of low-level toluene exposure on immunological biomarkers during different developmental stages in infant mice. Fetuses in utero in the pregnant mice on gestational day (GD) 14 as well as male pups on postnatal day (PND) 2 and PND 8 were exposed either to filtered air (control; 0 ppm), or to 5 ppm or to 50 ppm of toluene for 5 consecutive days in the whole body exposure chamber. Immunological biomarkers in the blood and spleen of PND 21 male mice were examined by ELISA, real-time RT-PCR, flow cytometry, and histological analysis. Plasma total IgG1 levels were markedly reduced in PND 21 mice exposed to 5 ppm of toluene during all developmental stages. Splenic T lymphocyte subsets and mRNA expression levels of Th1 cytokine IL-12, transcription factor T-bet, and Foxp3 were significantly suppressed in PND 21 male mice exposed to toluene during PNDs 8-12. There were changes in some immunological biomarkers in PND 42 mice exposed to toluene during PNDs 8-12. These findings indicate developmental stage-specific changes in non-specific immunological biomarkers in mice after early life toluene exposure.