Effects of enrofloxacin on antioxidant system, microsomal enzymatic activity, and proteomics in porcine liver

Enrofloxacin (EF) is a widely used fluoroquinolone, usually regarded as a safe and effective treatment for bacterial infections. Adverse effects of EF have previously been demonstrated in some species, but so far there have been no studies looking specifically at the impact of EF on pigs. In this study, three different doses of EF (5, 25 and 125mgkgbw(-1)) were administrated to Bama pigs. The results showed that lipid peroxidation of pig liver tissue occurred with all EF doses. The 125mgkg dose of EF induced catalase (CAT) and glutathione peroxidase (GSH-px) and increased CYP450 content in pig liver microsomes. The activity of microsomal NADPH-cytochrome C reductase (NCCR) was elevated at both the 25 and 125mgkg doses of EF. Microsomal erythromycin N-demethylase (ERND) and aminopyrin N-demethylase (AND) were inhibited by high doses of EF, while aniline-4-hydroxylase (AH) was unaffected. None of the EF treatments affected superoxide dismutase (SOD) or cytochrome b5 content. Antioxidases and microsomal enzymes may work together to resist the adverse effects of EF. Proteomic analysis revealed increased protein expression of carboxylesterase (CES) and alpha-enolase (ENO1) in microsomes as a stress response to EF. These results provide new information about the adverse effect of fluoroquinolones and help guide their usage more effectively in the clinic or animal breeding.