[Effects of sulfur dioxide on mRNA expression and activities of hepatic and pulmonary cytochrome P4502B1 and 2E1 in rats].

OBJECTIVE

To study the effects of sulfur dioxide (SO2) on activities and mRNA expression of hepatic and pulmonary cytochrome P4502B1 and 2E1 in rats.

METHODS

Male Wistar rats were housed in exposure chambers and treated with 14, 28 and 56 mg/m3 SO2 for 6 h/d for 7 days, while control rats were exposed to filtered air in the same condition. The activities of CYP2E1 of rats were measured by spectrophotometry. Fluorescence spectrophotometry was used to study the activities of CYP2B1. The mRNAs of CYP2B1 and 2E1 were analyzed in livers and lungs by using a reverse transcription-polymerase chain reaction (RT-PCR) assay.

RESULTS

In the liver, decreases of CYP2B1 activity and mRNA were observed at higher dose of SO2 (28 and 56 mg/m3). However, the CYP2E1-dependent p-nitrophenol hydroxylases (p-NP) and mRNA were unaltered by SO2 at all detected concentrations. For lungs, CYP2B1 activity was unaltered by SO2 at low concentrations, except for a significant decrease in the rats exposed to SO2 at 56mg/m3, however, SO2 at higher concentrations (28 and 56 mg/m3) significantly decreased CYP2B1 mRNA. Significant inhibition of p-NP was observed in lungs of rats exposed to SO2 at 28 and 56 mg/m3. SO2 at higher concentrations (28 and 56 mg/m3) decreased significantly pulmonary CYP2E1 mRNA relative to control animals.

CONCLUSION

It was suggested that SO2 exposure could suppress the activities and mRNA expression of hepatic CYP2B1 and pulmonary CYP2B1 and 2E1 of rats.