Melatonin suppresses cisplatin-induced nephrotoxicity via activation of Nrf-2/HO-1 pathway

Abstract

Background: Cisplatin, one of the most effective and potent anticancer drugs, is used in the treatment of a wide variety of both pediatric and adult malignancies. However, the chemotherapeutic use of cisplatin is limited by its serious side-effects such as nephrotoxicity and ototoxicity. Cisplatin chemotherapy induces a reduction in the antioxidant status, leading to a failure of the antioxidant defense against free-radical damage generated by antitumor drugs. Cisplatin-induced oxidative stress in the kidney was partially prevented by antioxidant treatments using superoxide dismutase, glutathione, selenium and flavonoids. Melatonin and its metabolites possess free-radical scavenging activity and it has been shown that they protect against cisplatin toxicity. However, the mechanism of the protective effects of melatonin against cisplatin-induced nephrotoxicity is still essentially unknown. We therefore designed this study to investigate the underlying mechanism of the protective effect of melatonin against cisplatin-induced renal damage in a rat nephrotoxicity model in vivo.

Methods: Twenty eight 8-week-old male Wistar rats were divided into four groups of control, melatonin treatment (4 mg/kg b.w i.p. for 10 days), cisplatin treatment (7 mg/kg b.w., i.p.) and melatonin and cisplatin combination treatment. Serum urea nitrogen (urea-N) and creatinine levels were measured. Histopathological changes were evaluated. In addition, we analyzed the expression levels of HO-1, Nrf2, NF-κB and AP-1 in Western blot analysis.

Results: Both serum creatinine and urea nitrogen increased significantly following cisplatin administration alone; these values decreased significantly with melatonin co-treatment of cisplatin-treated rats. Histological analysis showed that cisplatin caused damage in the proximal tubular cells in the kidneys of cisplatin-treated rats; these changes were reversed by melatonin co-treatment. Upon Western blot analysis, melatonin treatment increased Nrf2 accumulation in the nuclear fraction, and increased the expression of HO-1 in the cytosolic fraction as compared to the cisplatin-treated rats. Expressions of NF-κB p65 and AP-1 were increased significantly in the kidneys of rats treated with cisplatin compared with the expression in the kidneys from the control, melatonin-only-treated and melatonin co-treated rats.

Conclusion: Our present data suggest that melatonin attenuates cisplatin-induced nephrotoxicity possibly by modulating Nrf2/HO-1 signaling.

Figure 1

Western blot analysis of NF-κB p65, AP-1, Nrf2 (nuclear fraction) and HO-1 (cytosolic fraction) in kidney cells in rats: Western blot using the anti- NF-κB (Panel A), AP-1 (Panel B), Nrf2 (Panel C) and hemeoxygenese-1 (HO-1; Panel D) revealed specific bands. Blots were repeated at least 3 times. β-actin levels were monitored to ensure equal protein loading (bottom panel). The intensity of the bands was quantified by the densitometric analysis. Data are percent of the control. a-c: Means in the same line without a common superscript differ significantly (P < 0.05).

Figure 2

Histological changes in renal tissues in response to cisplatin and cisplatin+melatonin: The day when animals injected cisplatin is Day 0 and the histological changes in the renal tissues on day 10 are indicated. A, Control; B, melatonin treatment alone; C, cisplatin treatment alone [left to right (ii) interstitial inflammation, (v) vaculation, (ie) interstitial edema, (tn) tubular necrosis, (ta) tubular atrophy]; D, cisplatin+melatonin. Magnification: x 200.