Oxidative stress-induced renal telomere shortening as a mechanism of cyclosporine-induced nephrotoxicity

Due to the association of oxidative stress and telomere shortening, it was aimed in the present study to investigate the possibility whether cyclosporine-A exerts its nephrotoxic side effects via induction of oxidative stress-induced renal telomere shortening and senescent phenotype in renal tissues of rats. Renal oxidative stress markers, 8-hydroxydeoxyguanosine, malondialdehyde, and protein carbonyl groups were measured by standard methods. Telomere length and telomerase activity were also evaluated in kidney tissue samples. Results showed that cyclosporine-A treatment significantly (P < 0.05) enhanced renal malondialdehyde, 8-hydroxydeoxyguanosine, and protein carbonyl groups levels, decreased renal telomere length, and deteriorated renal function compared with the controls. Renal telomerase activity was not affected by cyclosporine-A. Renal telomere length could be considered as an important parameter of both oxidative stress and kidney function. Telomere shortening and accelerated kidney aging may be caused by cyclosporine-induced oxidative stress, indicating the potential mechanism of cyclosporine-induced nephrotoxicity.

The Effects of Valsartan on Renal Klotho Expression and Oxidative Stress in Alleviation of Cyclosporine Nephrotoxicity

BACKGROUND

Nephrotoxicity side effect of the immunosuppressive drug, cyclosporine A (CsA), can be a major issue in transplantation medicine. Cyclosporine A-induced nephrotoxicity is multifactorial but oxidative stress has a critical role in this process. It has been demonstrated that Valsartan (Val) as an angiotensin receptor blocker has renoprotective effects, but the molecular mechanisms responsible for the renal protection, independent from its blood pressure lowering effect, have not yet been fully understood. The present study is aim at evaluating the Val effect in alleviation of CsA nephrotoxicity by probable increase in renal Klotho expression and/or reducing oxidative stress.

METHODS

Thirty-two Sprague-Dawley rats were divided into 4 groups based on the administration of CsA and/or Val: group A (control, 1 mL/kg per day of olive oil as vehicle), group B (CsA, 30 mg/kg per day), group C (CsA + Val, 30 + 30 mg/kg per day), and group D (Val, 30 mg/kg per day). Real-time polymerase chain reaction and Western blotting were used to evaluate Renal Klotho expression. Serum Klotho level was measured by enzyme-linked immunosorbent assay. 8-Hydroxy-deoxy guanosine and malondialdehyde levels as markers of oxidative stress were measured by enzyme-linked immunosorbent assay and spectrophotometrically, respectively.

RESULTS

Cyclosporine A treatment reduced renal expression and serum levels of Klotho, improved malondialdehyde and 8-hydroxy-deoxy guanosine levels, and also deteriorated renal function. Valsartan prevented CsA-induced oxidative stress as well as Klotho downregulation and could alleviate CsA-induced renal histological changes and function.

CONCLUSIONS

Administration of Val might lead to amelioration of CsA nephrotoxicity by probably diminishing CsA-induced renal Klotho downregulation and oxidative stress.

Effects of Angiotensin II Receptor Blockade on Soluble Klotho and Oxidative Stress in Calcineurin Inhibitor Nephrotoxicity in Rats

INTRODUCTION

Calcineurin inhibitor nephrotoxicity is major problem after organ transplantation. It is multifactorial, but oxidative stress may have an important role in this process. It has been shown that angiotensin II receptor blockers have renoprotective effects but their molecular mechanism is largely unknown. Antioxidative effect is an important role of the recently known anti-aging protein, klotho. This study aimed to evaluate effect of valsartan in alleviation of cyclosporine A nephrotoxicity via a probable increase in serum klotho levels or decreasing oxidative stress.

MATERIALS AND METHODS

Thirty-two Sprague-Dawley rats were divided into 4 groups to receive 1 mL/kg/d of olive oil as control; 30 mg/kg/d of cyclosporine; 30 mg/kg/d of cyclosporine and 50 mg/kg/d of valsartan; and 50 mg/kg/d of valsartan. After the 6 weeks of administration period, serum levels of klotho and 8-hydroxydeoxyguanosine were measured using an enzyme-linked immunosorbent assay. Serum malondialdehyde level was measured spectrophotometrically.

RESULTS

The mean serum level of klotho was significantly lower in the cyclosporine group compared with control and valsartan groups. Klotho level in the valsartan group was significantly higher than those in the other groups. The cyclosporine group was detected to have significantly higher serum 8-hydroxydeoxyguanosine and malondialdehyde levels compared with the other study groups. The levels of klotho were negatively correlated with 8-hydroxydeoxyguanosine and malondialdehyde levels.

CONCLUSIONS

Administration of valsartan may lead to attenuation of the nephrotoxic side effect of cyclosporine via enhancing klotho and decreasing oxidative stress levels.

The effects of valsartan on renal glutathione peroxidase expression in alleviation of cyclosporine nephrotoxicity in rats

Introduction: Nephrotoxicity as a side effect caused by the immunosuppressive drug, cyclosporine-A (CsA), can be a major problem in transplant medicine. Oxidative stress may play an important role in the CsA-induced nephrotoxicity. It has been shown that the antihypertensive drug, valsartan (Val), has also renoprotective effects but, its molecular mechanism is largely unknown. In the present study, it was aimed to evaluate the Val effect in the alleviation of CsA nephrotoxicity via probable renal glutathione peroxidase (GPx) upregulation and oxidative stress decrease.

Methods: Thirty-two Sprague-Dawley rats were divided into four groups based on CsA and/or Val administration: group A (Control, 1 mL/kg/day of olive oil as vehicle), group B (CsA, 30 mg/kg/day), group C (CsA+Val, 30+30 mg/kg/day), and group D (Val, 30 mg/kg/day). After the administration period (six weeks), renal GPx expression was evaluated by real-time polymerase chain reaction (PCR). Plasma levels of GPx and 8-Hydroxydeoxyguanosine (8-OHdG) were measured by enzyme-linked immunosorbent assay (ELISA). Malondialdehyde (MDA) and protein carbonyl groups (PCG) were measured by spectrophotometer. Plasma levels of urea and creatinine were measured by an autoanalyzer.

Results: CsA treatment led to the decrease in renal expression and plasma levels of GPx in comparison to other study groups. Rats received CsA were detected to have significantly (p<0.05) higher plasma 8-OHdG, MDA, PCG, urea, and creatinine levels in comparison to other groups. Plasma urea and creatinine levels were negatively correlated with renal GPx expression and positively correlated with the oxidative stress markers.

Conclusion:Administration of Val may result in attenuating the nephrotoxic side effect of CsA via probable renal GPx upregulation, and subsequently oxidative stress decrease.