Influences of sub-acute exposure to paraquat on cytochrome P450 3A2 expression in rat liver and lungs

This study was designed to investigate the possible effects of paraquat sub-acute poisoning on cytochrome P450 3A2 expression in the liver and lungs. Twenty adult male rats (150–200 g) were exposed either against saline normal as control group or various doses of paraquat (3.5, 7 and 10 mg/kg, s.c.) as test groups for 7 consecutive days. Paraquat-exposed animals showed loss of body weight and elevation in serum levels of alkaline phosphates and alanine aminotransferase in a dose-dependent fashion. Moreover, animals in the test groups demonstrated a significant (P < 0.05) increase of malondialdehyde content in both the liver and lung tissues. Ultimately, by using RT-PCR method it became clear that 7 days exposure to paraquat resulted in a total suppression of cytochrome P450 3A2 at the mRNA level in the lungs. By contrast, a considerable up regulation of the same gene occurred in the liver. This data suggest that paraquat not only affect the lungs as a main target tissue but also up regulates the predominant cytochrome P450 gene in the liver which may induce detoxification processes.