Beneficial effects of quercetin on oxidative stress in liver and kidney induced by titanium dioxide (TiO₂) nanoparticles in rats

Abstract

TiO₂ nanoparticles used as vectors for the delivery of drugs have shown greater effectiveness. However, TiO₂ nanoparticles can cause oxidative stress in liver and kidney, so we analyzed if a previous or simultaneous quercetin treatment could counteract this in rats. Five groups of male Wistar rats (200–250 g) were included: (1) healthy controls, (2) TiO₂ group, (3) quercetin group, (4) preventive group: quercetin for 5 days prior to exposure of TiO₂, and (5) therapeutic group: TiO₂ (5 mg/kg, i.v.) plus quercetin single dose for 5 days (5 mg/kg/day, i.p.). Hepatic and renal function tests were made. Five animals from each group were sacrificed (0, 14 and 28 days), and liver and kidney tissue were obtained. Malondialdehyde (MDA), reduced/oxidized glutathione, and activity of glutathione peroxidase/reductase were measured, as well as the level of gene expression by q-PCR. There were no significant changes in serum ALT and AST activities. More damage was observed at 14 versus 28 days, because TiO₂ was excreted in urine. Quercetin indeed showed a renal protective effect by increasing glutathione reductase and peroxidase levels and reducing MDA levels. On the other hand, TiO₂ liver damage was less pronounced with quercetin as therapeutic treatment. TiO₂ induces significantly the glutathione reductase expression and it can be down-regulated by quercetin. Biochemical tests in serum and urine showed a better effect of quercetin administered in the therapeutic group. Care should be taken with the dose and time of administration of quercetin, because this antioxidant could also have a pro-oxidant effect.

• Kidney
• liver
• nanoparticles
• oxidative stress
• quercetin
• rat
• titanium dioxide (TiO₂)

Acknowledgements

We thank Professor Fernando Francisco Hernandez Clemente, M.S. (UNAM) for his assistance in reviewing the manuscript.

Declaration of interest

This work was supported in part by PROINPEP 2011, awarded to PhD Pharmacology program students.