Nephrotoxicity of high- and low-osmolar contrast media. The protective role of amlodipine in a rat model

Trends in contrast media research the last 100 years

This review focuses on the trends in contrast media (CM) research published in Acta Radiologica during the last 100 years, since the first edition in 1921. The main topics covered are the developments of iodine- and gadolinium-based CM. Other topics include manganese-based CM for magnetic resonance imaging (MRI) and barium for the investigation of the alimentary tract. From a historic point of view, special CM for use in cholegraphy and myelography are addressed in the review. Today, these imaging procedures are obsolete due to the development of computed tomography, MRI, and ultrasound. The historical use of radioactive thorium-based CM for angiography is also addressed. Furthermore, publications on adverse reactions to CM are reviewed.

Amlodipine alleviates cisplatin-induced nephrotoxicity in rats through gamma-glutamyl transpeptidase (GGT) enzyme inhibition, associated with regulation of Nrf2/HO-1, MAPK/NF-κB, and Bax/Bcl-2 signaling

BACKGROUND

The therapeutic utility of the effective chemotherapeutic agent cisplatin is hampered by its nephrotoxic effect. We aimed from the current study to examine the possible protective effects of amlodipine through gamma-glutamyl transpeptidase (GGT) enzyme inhibition against cisplatin nephrotoxicity.

METHODS

Amlodipine (5 mg/kg, po) was administered to rats for 14 successive days. On the 10th day, nephrotoxicity was induced by a single dose of cisplatin (6.5 mg/kg, ip). On the last day, blood samples were collected for estimation of kidney function, while kidney samples were used for determination of GGT activity, oxidative stress, inflammatory, and apoptotic markers, along with histopathological evaluation.

RESULTS

Amlodipine alleviated renal injury that was manifested by significantly diminished serum creatinine and blood urea nitrogen levels, compared to cisplatin group. Amlodipine inhibited GGT enzyme, which participates in the metabolism of extracellular glutathione (GSH) and platinum-GSH-conjugates to a reactive toxic thiol. Besides, amlodipine diminished mRNA expression of NADPH oxidase in the kidney, while enhanced the anti-oxidant defense by activating Nrf2/HO-1 signaling. Additionally, it showed marked anti-inflammatory response by reducing expressions of p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-kappa B (NF-κB), with subsequent down-regulation of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and vascular cell adhesion molecule-1 (VCAM-1). Moreover, amlodipine reduced Bax/Bcl-2 ratio and elevated hepatocyte growth factor (HGF), thus favoring renal cell survival.

CONCLUSIONS

Effective GGT inhibition by amlodipine associated with enhancement of anti-oxidant defense and suppression of inflammatory signaling and apoptosis support our suggestion that amlodipine could replace toxic GGT inhibitors in protection against cisplatin nephrotoxicity.

The immunohistochemical and histologic effects of contrast medium on uterus, fallopian tubes and ovaries, given during hysterosalpingography: rat study

Objective:

Previous studies have shown that damage occurs to internal genital tract during hysterosalpingography (HSG). The aim was to show that endometrial and tubal epithelium underwent free radical damage during HSG in an animal model.

Material and Methods:

Forty rats were evaluated in five different groups. Two groups received ionizing radiation (15-20 miliRad three times) only. Two further groups received ionizing radiation in combination with iohexol (1-2 mL). The remaining group served as control. Groups were evaluated after seven and forty-two days. Inflammation and cellular changes were evaluated histopathologically. Cellular activity of antioxidant enzymes was assessed immunohistochemically.

Results:

Inflammation, and cellular changes were detected at certain rates in all groups (p<0.001). Glutathione reductase, catalase, superoxide dismutase, glutathione S-transferase activities were found to be increased after the HSG (p<0.001).

Conclusion:

It is obvious that the cell suffers acute and chronic damage during HSG due to both radioactivity and chemicals. Although there is a lot of research done before, there is no definitive method yet to protect against the harmful effects of iodinated contrast agents and ionizing radiation. So, new methods need to be explored to protect cells and tissues from reactive oxygen radical damage caused by HSG.

Protective Effects of Amlodipine Pretreatment on Contrast-Induced Acute Kidney Injury And Overall Survival In Hypertensive Patients

Backgroud

Contrast-induced acute kidney injury (CI-AKI) is the most common adverse reaction caused by contrast media, which has been reported to prolong hospitalization and increase mortality and morbidity. The hypertensive population has proved susceptible to CI-AKI. Unfortunately, no therapeutic has been shown to prevent and cure CI-AKI effectively. A few studies have shown the protection of amlodipine on renal function, but the relationship between amlodipine and CI-AKI in hypertensive group is unknown, we aimed to study the effects of amlodipine on CI-AKI and overall survival in a large Chinese hypertensive cohort.

Methods

A retrospective, matched, cohort study was conducted among adults hospitalized at the Third Xiangya Hospital of Central South University from October 2007 to May 2017. CI-AKI was the primary end point of the trial, time-related all-cause mortality (including in-hospital) and length of hospital stay were the secondary end points. Propensity Score Matching was used to reduce the effect of selection bias and potential confounding.

Results

868 patients with and 1,798 ones without amlodipine before contrast administration were included. The incidence of CI-AKI was 10.50%. The unadjusted, adjusted, and propensity‐score matched incidence of CI-AKI were lower in patients treated with amlodipine (OR, 0.650; P = 0 .003; OR, 0.577; P = 0.007; OR, 0.687; P = 0.015, respectively), and the same results were found in the subgroups of diabetes, chronic kidney disease (CKD), non-CKD, low-osmolar, and elderly. Moreover, amlodipine reduced hospital stay, whether matched or not (7.08 ± 7.28 vs 7.77 ± 7.82, P = 0.027, before matching; vs 7.81 ± 7.58, P = 0.040, after matching). 1,046 patients finished follow-up including 343 amlodipine users and 703 non-users. The overall mortality was significantly lower among amlodipine users (10.79%) than controls (16.07%), the significant difference was found in survival between them (P = 0.024, log-rank test), amlodipine was associated with longer overall survival [HR, 0.623; 95% CI (0.430–0.908), P = 0.014].

Conclusion

In conclusion, we first found amlodipine treatment before contrast exposure played a role in protecting hypertensive patients from CI-AKI and prolonging survival.

Contrast Induced Acute Kidney Injury and Direct Cytotoxicity of Iodinated Radiocontrast Media on Renal Proximal Tubule Cells

The administration of intravenous iodinated radiocontrast media (RCM) to visualize internal structures during diagnostic procedures has increased exponentially since their first use in 1928. A serious side effect of RCM exposure is contrast-induced acute kidney injury (CI-AKI), which is defined as an abrupt and prolonged decline in renal function occurring 48-72 hours after injection. Multiple attempts have been made to decrease the toxicity of RCM by altering ionic strength and osmolarity, yet there is little evidence to substantiate that a specific RCM is superior in avoiding CI-AKI. RCM-associated kidney dysfunction is largely attributed to alterations in renal hemodynamics, specifically renal vasoconstriction; however, numerous studies indicate direct cytotoxicity as a source of epithelial damage. Exposure of in vitro renal proximal tubule cells to RCM has been shown to affect proximal tubule epithelium in the following manner: 1) changes to cellular morphology in the form of vacuolization; 2) increased production of reactive oxygen species, resulting in oxidative stress; 3) mitochondrial dysfunction, resulting in decreased efficiency of the electron transport chain and ATP production; 4) perturbation of the protein folding capacity of the endoplasmic reticulum (ER) (activating the unfolded protein response and inducing ER stress); and 5) decreased activity of cell survival kinases. The present review focuses on the direct cytotoxicity of RCM on proximal tubule cells in the absence of in vivo complications, such as alterations in renal hemodynamics or cytokine influence.

Update on the renal toxicity of iodinated contrast drugs used in clinical medicine

An important side effect of diagnostic contrast drugs is contrast-induced acute kidney injury (CI-AKI; a sudden decrease in renal function) occurring 48-72 hours after injection of a contrast drug that cannot be attributed to other causes. Its existence has recently been challenged, because of some retrospective studies in which the incidence of AKI was not different between subjects who received a contrast drug and those who did not, even using propensity score matching to prevent selection bias. For some authors, only patients with estimated glomerular filtration rate <30 mL/min/1.73 m2 are at significant risk of CI-AKI. Most agree that when renal function is normal, there is no CI-AKI risk. Many experimental studies, however, are in favor of the existence of CI-AKI. Contrast drugs have been shown to cause the following changes: renal vasoconstriction, resulting in a rise in intrarenal resistance (decrease in renal blood flow and glomerular filtration rate and medullary hypoxia); epithelial vacuolization and dilatation and necrosis of proximal tubules; potentiation of angiotensin II effects, reducing nitric oxide (NO) and causing direct constriction of descending vasa recta, leading to formation of reactive oxygen species in isolated descending vasa recta of rats microperfused with a solution of iodixanol; increasing active sodium reabsorption in the thick ascending limbs of Henle's loop (increasing O2 demand and consequently medullary hypoxia); direct cytotoxic effects on endothelial and tubular epithelial cells (decrease in release of NO in vasa recta); and reducing cell survival, due to decreased activation of Akt and ERK1/2, kinases involved in cell survival/proliferation. Prevention is mainly based on extracellular volume expansion, statins, and N-acetylcysteine; conflicting results have been obtained with nebivolol, furosemide, calcium-channel blockers, theophylline, and hemodialysis.

A new update for radiocontrast-induced nephropathy aggravated with glycerol in rats: the protective potential of epigallocatechin-3-gallate

Contrast media (CM) is known to have nephrotoxic adverse effects. Epigallocatechin-3-gallate (EGCG) is the most abundant and active catechin in green tea, and has strong antioxidant and anti-inflammatory properties. This study investigated whether EGCG can reduce contrast-induced nephrotoxicity (CIN), alone or with glycerol (GLY)-induced renal damage, and to understand its mechanisms of protection against toxicity, using models of GLY and CIN in rats. The rats were separated into eight groups (n = 6 in each), as follows: Healthy, GLY, CM, GLY + CM, CM + EGCG 50 mg/kg (po), GLY + CM + EGCG 50 mg/kg (po), CM + EGCG 100 mg/kg (po), and GLY + CM + EGCG 100 mg/kg (po). Both doses of EGCG protected against CM-induced renal dysfunction, as measured by serum creatinine and blood urea nitrogen (BUN). In addition, EGCG treatment markedly improved CIN-induced oxidative stress, and resulted in a significant down-regulatory effect on tumor necrosis factor (TNF)-α and nuclear factor (NF)-κB mRNA expression. Moreover, histopathological analysis showed that EGCG also attenuated CM-induced kidney damage. Considering the potential clinical use of CM and the numerous health benefits of EGCG, this study showed the protective role of multi-dose EGCG treatment on CIN and GLY-aggravated CIN through different mechanisms.

Protective effect of quinacrine against glycerol-induced acute kidney injury in rats

BACKGROUND

Acute kidney injury (AKI) is a serious clinical problem with high rate of mortality and morbidity. Currently used prophylactic and therapeutic strategies to address AKI are limited and warrant further studies. In the present study an attempt was made to investigate the effect of quinacrine, a phospholipase A2 inhibitor against glycerol induced AKI in rats.

METHODS

Adult female Wistar rats were divided in to five groups. After 24 h of water deprivation rats in groups 3, 4 and 5 received an intraperitoneal injection of quinacrine (3 mg/kg, 10 mg/kg and 30 mg/kg of body weight respectively). Thirty minutes after the first injection of quinacrine animals in groups 3, 4 and 5 received an intramuscular injection of 25% glycerol (10 ml/kg of body weight). The animals in group 2 received 25% glycerol (10 ml/kg of body weight) only whereas rats in group 1 served as control . The quinacrine administration was continued once daily for three days, on the fourth day animals were sacrificed, blood and kidney were collected for various biochemical and histopathological studies.

RESULTS

Glycerol treatment produced significant renal structural abnormalities and functional impairment (increased urea and creatinine). Increase in myeloperoxidase (MPO) and malondialdehyde (MDA) clearly suggested the involvement of oxidative stress and neutrophilic activity following glycerol administration. Quinacrine dose dependently attenuated glycerol induced structural and functional changes in kidney.

CONCLUSION

The reversal of glycerol induced AKI by quinacrine points towards a role of phospholipase A2 (PLA2) in the pathogenesis of renal injury. The result of this study suggests that quinacrine may offer an alternative mode of treatment for AKI.

Histopathological Evaluation of Contrast-Induced Acute Kidney Injury Rodent Models

Contrast-induced acute kidney injury (CI-AKI) can occur in 3–25% of patients receiving radiocontrast material (RCM) despite appropriate preventive measures. Often patients with an atherosclerotic vasculature have to receive large doses of RCM. Thus, animal studies to uncover the exact pathomechanism of CI-AKI are needed. Sensitive and specific histologic end-points are lacking; thus in the present review we summarize the histologic appearance of different rodent models of CI-AKI. Single injection of RCM causes overt renal damage only in rabbits. Rats and mice need an additional insult to the kidney to establish a clinically manifest CI-AKI. In this review we demonstrate that the concentrating ability of the kidney may be responsible for species differences in sensitivity to CI-AKI. The most commonly held theory about the pathomechanism of CI-AKI is tubular cell injury due to medullary hypoxia. Thus, the most common additional insult in rats and mice is some kind of ischemia. The histologic appearance is tubular epithelial cell (TEC) damage; however severe TEC damage is only seen if RCM is combined by additional ischemia. TEC vacuolization is the first sign of CI-AKI, as it is a consequence of RCM pinocytosis and lysosomal fusion; however it is not sensitive as it does not correlate with renal function and is not specific as other forms of TEC damage also cause vacuolization. In conclusion, histopathology alone is insufficient and functional parameters and molecular biomarkers are needed to closely monitor CI-AKI in rodent experiments.

A novel approach to contrast-induced nephrotoxicity: the melatonergic agent agomelatine

OBJECTIVE

To study the potential nephroprotective role of agomelatine in rat renal tissue in cases of contrast-induced nephrotoxicity (CIN). The drug's action on the antioxidant system and proinflammatory cytokines, superoxide dismutase (SOD) activity, levels of glutathione (GSH) and malondialdehyde (MDA) and the gene expression of interleukin-6 (IL-6), tumour necrosis factor (TNF)-α and nuclear factor kappa B (NF-κB) was measured. Tubular necrosis and hyaline and haemorrhagic casts were also histopathologically evaluated.

METHODS

The institutional ethics and local animal care committees approved the study. Eight groups of six rats were put on the following drug regimens: Group 1: healthy controls, Group 2: GLY (glycerol), Group 3: CM (contrast media--iohexol 10 ml kg(-1)), Group 4: GLY+CM, Group 5: CM+AGO20 (agomelatine 20 mg kg(-1)), Group 6: GLY+CM+AGO20, Group 7: CM+AGO40 (agomelatine 40 mg kg(-1)) and Group 8: GLY+CM+AGO40. The groups were evaluated by one-way analysis of variance and Duncan's multiple comparison test.

RESULTS

Agomelatine administration significantly improved the serum levels of blood urea nitrogen (BUN) and creatinine, SOD activity, GSH and MDA. The use of agomelatine had substantial downregulatory consequences on TNF-α, NF-κB and IL-6 messenger RNA levels. Mild-to-severe hyaline and haemorrhagic casts and tubular necrosis were observed in all groups, except in the healthy group. The histopathological scores were better in the agomelatine treatment groups.

CONCLUSION

Agomelatine has nephroprotective effects against CIN in rats. This effect can be attributed to its properties of reducing oxidative stress and inhibiting the secretion of proinflammatory cytokines (NF-κB, TNF-α and IL-6).

ADVANCES IN KNOWLEDGE

CIN is one of the most important adverse effects of radiological procedures. Renal failure, diabetes, malignancy, old age and non-steroidal anti-inflammatory drug use pose the risk of CIN in patients. Several clinical studies have investigated ways to avoid CIN. Theophylline/aminophylline, statins, ascorbic acid and iloprost have been suggested for this purpose. Agomelatine is one of the melatonin ligands and is used for affective disorders and has antioxidant features. In this study, we hypothesized that agomelatine could have nephroprotective, antioxidant and anti-inflammatory effects against CIN in rats.

Nephroprotective potential of carnitine against glycerol and contrast-induced kidney injury in rats through modulation of oxidative stress, proinflammatory cytokines, and apoptosis

OBJECTIVE

Contrast media (CM) are a major cause of nephropathy in high-risk patients. The aim of this study was to examine the effects of carnitine (CAR) in advanced nephrotoxicity due to CM administration in rats with glycerol-induced renal functional disorder.

METHODS

40 rats were divided randomly into five groups (n = 8): (1) healthy group; (2) glycerol only (GLY); (3) glycerol and CM (GLY + CM); (4) glycerol, CM and 200 mg kg(-1) carnitine (CAR200, Carnitene(®); Sigma-tau/Santa Farma, Istanbul, Turkey); and (5) glycerol, CM and 400 mg kg(-1) carnitine (CAR400). Kidney injury was induced with a single-dose, intramuscular injection of 10 ml kg(-1) body weight (b.w.) of GLY. CAR was administered intraperitoneally. CM (8 ml kg(-1) b.w. iohexol, Omnipaque™; Opakim Medical Products, Istanbul, Turkey) was infused via the tail vein to the rats in Groups 3-5.

RESULTS

l-carnitine administration significantly decreased serum creatinine and blood urea nitrogen levels. Superoxide dismutase and glutathione activity increased significantly in the treatment groups compared with the nephrotoxic groups. CAR400 significantly reduced malondialdehyde levels to healthy levels. In the treatment groups, tumour necrosis factor (TNF)-α, transforming growth factor 1β, interleukin 1β and caspase-3 gene expression decreased compared with the nephrotoxic groups. TNF-α and nuclear factor kappa-beta (NF-κB) protein expression increased after CM and CAR administration reduced both TNF-α and NF-κB expressions. Histopathologically, hyaline and haemorrhagic casts and necrosis in proximal tubules increased in the nephrotoxicity groups and decreased in the CAR groups.

CONCLUSION

The results reveal that l-carnitine protects the oxidant/antioxidant balance and decreases proinflammatory cytokines and apoptosis in CM-induced nephrotoxicity in rats with underlying pathology.

ADVANCES IN KNOWLEDGE

Depending on the underlying kidney pathologies, the incidence of CM-induced nephropathy (CIN) increases. Therefore, this is the best model to represent clinically observed CIN.

Prevention of contrast-induced nephropathy through a knowledge of its pathogenesis and risk factors

Contrast-induced nephropathy (CIN) is an iatrogenic acute renal failure (ARF) occurring after the intravascular injection of iodinated radiographic contrast media. During the past several years, in many patients undergoing computed tomography, iodinated contrast media have not been used for the fear of ARF, thereby compromising the diagnostic procedure. But recent studies have demonstrated that CIN is rarely occurring in patients with normal renal function and that preexisting chronic renal failure and/or diabetes mellitus represent(s) predisposing condition(s) for its occurrence. After the description of CIN and its epidemiology and pathophysiology, underlying the important role played by dehydration and salt depletion, precautions for prevention of CIN are listed, suggested, and discussed. Maximum priority has to be given to adequate hydration and volume expansion prior to radiographic procedures. Other important precautions include the need for monitoring renal function before, during, and after contrast media injection, discontinuation of potentially nephrotoxic drugs, use of either iodixanol or iopamidol at the lowest dosage possible, and administration of antioxidants. A long list of references is provided that will enable readers a deep evaluation of the topic.

Role of intracellular Ca2+ and Na+/Ca2+ exchanger in the pathogenesis of contrast-induced acute kidney injury

The precise mechanisms underlying contrast-induced acute kidney injury (CI-AKI) are not well understood. Intracellular Ca²⁺ overload is considered to be a key factor in CI-AKI. Voltage-dependent Ca²⁺ channel (VDC) and Na⁺/Ca²⁺ exchanger (NCX) system are the main pathways of intracellular Ca²⁺ overload in pathological conditions. Here, we review the potential underlying mechanisms involved in CI-AKI and discuss the role of NCX-mediated intracellular Ca²⁺ overload in the contrast media-induced renal tubular cell injury and renal hemodynamic disorder.

Simvastatin attenuates contrast-induced nephropathy through modulation of oxidative stress, proinflammatory myeloperoxidase, and nitric oxide

Contrast media- (CM-) induced nephropathy is a serious complication of radiodiagnostic procedures. Available data suggests that the development of prophylaxis strategies is limited by poor understanding of pathophysiology of CM-induced nephropathy. Present study was designed to determine the role of oxidative stress, myeloperoxidase, and nitric oxide in the pathogenesis of iohexol model of nephropathy and its modification with simvastatin (SSTN). Adult Sprague Dawley rats were divided into seven groups. After 24 h of water deprivation, all the rats except in control and SSTN-only groups were injected (10 ml/kg) with 25% glycerol. After 30 min, SSTN (15, 30, and 60 mg/kg) was administered orally, daily for 4 days. Twenty-four hours after the glycerol injection, iohexol was infused (8 ml/kg) through femoral vein over a period of 2 min. All the animals were sacrificed on day 5 and blood and kidneys were collected for biochemical and histological studies. The results showed that SSTN dose dependently attenuated CM-induced rise of creatinine, urea, and structural abnormalities suggesting its nephroprotective effect. A significant increase in oxidative stress (increased lipid hydroperoxides and reduced glutathione levels) and myeloperoxidase (MPO) and decreased nitric oxide in CM group were reversed by SSTN. These findings support the use of SSTN to combat CM-induced nephrotoxicity.

Differential roles of dihydropyridine calcium antagonist nifedipine, nitrendipine and amlodipine on gentamicin-induced renal tubular toxicity in rats

In the present study, we investigated the antioxidative potencies of dihydropyridine calcium antagonists prototype nifedipine, the second generation drug nitrendipine, and the long acting, third generation drug amlodipine on gentamicin-induced renal tubular toxicity in Sprague-Dawley rats. In addition, we analyzed the relationship between renal tubular cell apoptosis and the antioxidative properties of these dihydropyridine calcium antagonists. Results showed that treatment with gentamicin alone caused significant changes in the levels of urinary protein, urinary N-acetyl-beta-d-glucosaminidase, serum creatinine, and blood urea nitrogen. Nifedipine and amlodipine effectively reversed the effect of gentamicin on these parameters. In contrast, nitrendipine either had no effect or worsened gentamicin-induced changes in the levels of urinary protein, urinary N-acetyl-beta-d-glucosaminidase, serum creatinine, and blood urea nitrogen. Furthermore, gentamicin treatment caused significant increases in the levels of malondialdehyde, nitric oxide, nitric oxide synthase and significant decreases in the levels of reduced glutathione, glutathione-S-transferase, and superoxide dismutase in kidney tissues. These effects were dramatically reduced by nifedipine and amlodipine but not affected by nitrendipine. In addition to the biochemical changes, histopathological studies showed that gentamicin caused structural damages in the kidneys; renal tubular cell apoptosis, a decrease in Bcl-2 expression and an increase in Bax expression were observed in all rats treated with gentamicin, nifedipine and amlodipine effectively reversed the effect of gentamicin while nitrendipine worsened them. In conclusion, this study clearly indicated that nifedipine and amlodipine protected against gentamicin-induced nephrotoxicity while nitrendipine had little effect, or even worsened.

Differential effects of dihydropyridine calcium antagonists on doxorubicin-induced nephrotoxicity in rats

The aim of this study was to compare the roles of dihydropyridine calcium antagonists nifedipine, nitrendipine, amlodipine on doxorubicin (DXR)-induced nephrotoxicity in rats using biochemical, histopathological and immunohistochemical approaches. Male Sprague-Dawley rats were randomly divided into five experimental groups: control; DXR; DXR+nifedipine (15 mg/kg); DXR+nitrendipine (10 mg/kg); DXR+amlodipine (5 mg/kg). Results showed that treatment with DXR alone caused significant changes in the levels of urinary protein, serum creatinine (SCr), and blood urea nitrogen (BUN). Co-administration with amlodipine effectively reversed the effect of DXR on these parameters. In contrast, nifedipine and nitrendipine either had no effect or worsened DXR induced changes in the levels of urinary protein, SCr and BUN. Furthermore, DXR treatment caused significant increases in the levels of malondialdehyde (MDA), nitric oxide (NO), nitric oxide synthase (NOS) and significant decreases in the levels of reduced glutathione (GSH), glutathione-S-transferase (GST), and superoxide dismutase (SOD). These effects were significantly reduced by co-administration with amlodipine but not affected by nifedipine and worsened by nitrendipine. In addition to the biochemical changes, histopathological studies showed that DXR caused significant structural damages in the kidneys. Glomerular cell apoptosis, a decrease in Bcl-2 expression and an increase in Bax expression were observed in all rats treated with DXR. Co-administration with amlodipine effectively reversed the effect of DXR while nifedipine and nitrendipine had no effect. In conclusion, this study clearly indicated that amlodipine protected against DXR-induced nephrotoxicity while nifedipine and nitrendipine had no effect.