Abstract
4-nitrophenol (PNP), a chemical material, is generally regarded as an environmental endocrine disruptor. Phytosterin (PS), a new feed additive, possesses the highly efficient antioxidant activities. Transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf2) is an important regulator of cellular oxidative stress. This study examined the PNP-induced testicular oxidative damage and the PS-mediated protective actions in rats. The generation of MDA and H2O2 upon PNP and PS treatment was lower than that of PNP alone. These effects were accompanied by partially reversed levels of SOD, CAT, GSH and GSH-Px, though there was no return to normal. Moreover, PNP significantly reduced the caudal epididymal sperm counts and serum testosterone levels. Typical morphological changes were also observed in the testes of PNP-treated animals. PNP reduced the transcriptional level of Nrf2 as evaluated by RT-PCR, but promoted the dissociation from the Nrf2 complex, stabilization and translocation into the nucleus as evaluated by immunohistochemistry and western blot. Moreover, there was also an increased nuclear translocation upon PS treatment alone. In addition, PNP enhanced Nrf2-dependent gene expression of heme oxygenase-1 (HO-1) and Glutamate-cysteine ligase catalytic subunit (GCLC), however, simultaneous supplementation with PS restored these parameters near to the control. These results suggest that the Nrf2 pathway play an important role in PNP-induced oxidative damage and PS possesses attenuating effects on PNP-induced oxidative damage in rat testes.
