Protective Effect of Edaravone Against Cyclosporine-Induced Chronic Nephropathy Through Antioxidant and Nitric Oxide Modulating Pathways in Rats

Abstract

Background: Cyclosporine A (CsA) is an immunosuppressant with therapeutic indications in various immunological diseases; however, its use is associated with chronic nephropathy. Oxidative stress has a crucial role in CsA-induced nephrotoxicity. The present study evaluates the protective effect of edaravone on CsA-induced chronic nephropathy and investigates its antioxidant and nitric oxide modulating property.

Methods: Male Sprague-Dawley rats (n=66) were distributed into nine groups, including a control (group 1) (n=7). Eight groups received CsA (15 mg/kg) for 28 days while being treated. The groups were categorized as: Group 2: Vehicle (n=10)Groups 3, 4, and 5: Edaravone (1, 5, and 10 mg/kg) (n=7 each)Group 6: Diphenyliodonium chloride, a specific endothelial nitric oxide synthase (eNOS) inhibitor (n=7)Group 7: Aminoguanidine, a specific inducible nitric oxide synthase (iNOS) inhibitor (n=7)Group 8: Edaravone (10 mg/kg) plus diphenyliodonium chloride (n=7)Group 9: Edaravone (10 mg/kg) plus aminoguanidine (n=7) Blood urea nitrogen and serum creatinine levels, malondialdehyde, superoxide dismutase, and glutathione reductase enzyme activities were measured using standard kits. Renal histopathological evaluations and measurements of eNOS and iNOS gene expressions by RT-PCR were also performed. Data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey's test (SPSS software version 18.0).

Results: Edaravone (10 mg/kg) significantly attenuated CsA-induced oxidative stress, renal dysfunction, and kidney tissue injury. Aminoguanidine improved the renoprotective effect of edaravone. Edaravone reduced the elevated mRNA level of iNOS, but could not alter the level of eNOS mRNA significantly.

Conclusion: Edaravone protects against CsA-induced chronic nephropathy using antioxidant property and probably through inhibiting iNOS gene expression.

Keywords: Cyclosporine; Edaravone; Kidney diseases; Nitric oxide; eNOSe; iNOS.

Figure 1

Effect of edaravone (1, 5, 10 mg/kg), diphenyliodonium chloride (4 mg/kg), and aminoguanidine (100 mg/kg) on blood urea nitrogen (A), and serum creatinine (B) levels in CsA-treated rats. Data expressed as mean±SEM (one-way ANOVA followed by Tukey’s test). CsA: Cyclosporine A; Eda: Edaravone; DPI: Diphenyliodonium chloride; AG: Aminoguanidine.

Figure 2

Masson´s trichrome stained sections of rat kidneys: (A) renal cortex of rats treated with vehicle shows no specific pathologic change. (B) Tubular atrophy is seen in the cortex of CsA-treated rats. (C) Vascular thickening is seen in CsA-treated rats. (D) Mild patchy interstitial fibrosis is seen in CsA-treated rats. (E) Mild patchy interstitial inflammatory cells infiltration is seen in CsA-treated rats. (F) Renal cortex of rats treated with edaravone (10 mg/kg) plus CsA shows near normal morphology.

Figure 3

Effect of edaravone (10 mg/kg) on renal eNOS and iNOS mRNA levels in CsA-treated rats. Data expressed as mean±SEM. †††P<0.001 as compared to vehicle group; ***P<0.001 as compared to CsA-treated group; CsA: Cyclosporine.