Effect of oral administration of magnesium on Cisplatin-induced nephrotoxicity in normal and streptozocin-induced diabetic rats

Nigella sativa L. and its bioactive and nutraceutical components in the management of diabetic peripheral neuropathy

Diabetes-induced hyperglycemia leads to excessive production of oxygen free radicals, inflammatory cytokines, and oxidative stress, which initiates diabetic peripheral neuropathy (DPN). Currently, this condition affects 20% of adults with diabetes. Despite significant advances in the treatment of diabetes, the incidence of its complications, including DPN, is still high. Thus, there is a growing research interest in developing more effective and treatment approaches with less side effects for diabetes and its complications. Nigella sativa L. (NS) has received much research attention as an antioxidant, anti-yperglycemic factor, and anti-inflammatory agent. This natural compound demonstrates its antidiabetic neuropathy effect through various pathways, including the reduction of lipid peroxidation, the enhancement of catalase and superoxide dismutase enzyme activity, and the decrease in inflammatory cytokine levels. The present review focuses on the bioactive and nutraceutical components of black cumin (Nigella sativa L.) and their effects on DPN. In addition, we have also summarized the findings obtained from several experimental and clinical studies regarding the antidiabetic neuropathy effect of NS in animal models and human subjects.

The Prevention of Cisplatin-Induced Nephrotoxicity: A General Consensus Statement of a Group of Oncologist-Hematologists, Adult and Pediatric Nephrologists, Radiation Oncologists, Clinical Pathologists, Clinical Pharmacologists, and Renal Physiologists on Cisplatin Therapy in Cancer Patients

Backgrounds

Most of the cancer patients with solid tumor are subjected to chemotherapy with cisplatin (CP) in clinic. However, the most side effect of CP is nephrotoxicity, which limits the treatment. The aim of study was to develop a general consensus statement for CP therapy in clinic to limit the drug-induced nephrotoxicity.

Methods

A total of 30 oncologist-hematologists, adult and pediatric nephrologists, radiation oncologists, clinical pathologist clinical pharmacologist, and renal physiologist participated in a workshop, and in order to reduce the incidence of CP-induced nephrotoxicity, a general consensus was developed.

Results

The developed general consensus was focused on some items such as age, sex, female hormone, nonsteroidal anti-inflammatory drugs (NSAID), renin-angiotensin system inhibitor drugs, glomerular filtration rate, hydration methods, contrasts, antioxidants, dextrose, and magnesium.

Conclusion

The agreement between participants for CP therapy in clinic was achieved, and this general consensus was announced to be implemented in the hospitals.

Intravenous Administration of Cisplatin with Magnesium Sulfate Supplement May Prevent Kidney Toxicity in Rats: The Role of Gender and Magnesium Sulfate Dose

Background. Cisplatin (CP) is widely used to treat various kinds of malignancies, but to avoid its side effects of nephrotoxicity and hypomagnesemia, magnesium supplementation is a subject of debate. The current study was designed to determine the protective role of intravenous magnesium sulfate (MgSO4) against intravenous administration of CP in male and female rats. Method. In this case-control experimental study, 80 Wistar male and female rats in 12 groups of experiments were subjected to receive intravenous administration of CP accompanied with intravenous infusion of different doses (1, 3, and 10 mg/ml solution) of MgSO4 and were compared with the control groups. Results. CP administration increased blood urea nitrogen (BUN), creatinine (Cr), kidney tissue damage score (KTDS), and kidney weight (KW), and they were attenuated by the mid-dose of MgSO4 supplementation in female rats. However, in male rats, the increase of Cr, BUN, KTDS, and KW induced by CP was ameliorated by low, mid-, and high doses of MgSO4 supplements. The levels of these markers were significantly different between male and female rats in the mid-dose of MgSO4-treated group (BUN: $P=0.002$ , Cr: $P=0.005$ , KTDS: $P=0.002$ , and KW: $P=0.031$ ). CP reduced clearance of Cr (ClCr) in both male and female rats significantly compared to the control group of saline alone (Pmale = 0.002 and Pfemale = 0.001), and the mid- and high doses of MgSO4 supplements improved ClCr in female rats. There were also sex differences in ClCr in mid- ( $P=0.05$ ) and high ( $P=0.032$ ) doses of MgSO4-treated groups. CP accompanied with the mid-dose of MgSO4 supplement reduced the KTDS (Pmale = 0.04 and Pfemale = 0.004) and KW (Pmale = 0.002 and Pfemale = 0.042) in both male and female rats significantly when compared with the CP-alone-treated group, while there were also significant differences between the sexes (KTDS: $P=0.002$ and KW: $P=0.031$ ). CP accompanied with three different doses of MgSO4 supplements did not improve the serum levels of lactate dehydrogenase, urine level of sodium, malondialdehyde, urine flow, and nitrite statistically when compared with the CP-alone-treated group. Conclusion. The renal protective effect of MgSO4 could be dose and gender related.

Hepatoprotective effect of ferulic acid and/or low doses of γ-irradiation against cisplatin-induced liver injury in rats

The therapeutic efficacy of cisplatin (CIS) is limited owing to its hepatotoxic side effects. The current study aimed to investigate the protective impact of ferulic acid (FA) and low-doses of γ-irradiation (LDR) against CIS-prompted hepatotoxicity in rats. Adult male Swiss albino rats were divided into eight groups: untreated group; FA, LDR, and CIS treated groups; and combinations of one or more of the above treatments. Post-treatment analyses included measuring redox markers like SOD and CAT activity, NO free radical content, and lipid peroxidation in liver tissue. Serum aminotransferase activities were also determined. Additionally, gene transcript levels of liver NF-ҡB-P65, caspase-1, COX-2, and IL-1β were quantified. Moreover, immunohistochemistry for caspase-3 and histopathological examinations were estimated in liver tissue. Our findings revealed increased levels of oxidative stress along with a significant reduction in anti-oxidative responses and a significant increase in serum aminotransferase activities in the CIS-intoxicated group. A similar increase was also observed in COX-2 and IL-1β transcript levels and caspase-3 enzyme activity, besides a decrease in transcript levels of NF-ҡB-p65 and caspase-1, indicating an overall inflammatory trend and an increase in the apoptotic shift. The co-administration of FA and/or treatment with LDR has ameliorated the hepatotoxic effect induced by CIS. The histopathological investigation of liver tissues confirmed this ameliorating action of these adjuvant therapies against CIS toxicity. In conclusion, it is plausible to suggest that the hepatoprotective effects of co-administration of FA and/or LDR against CIS-induced hepatotoxicity are attributed to the possession of anti-oxidative, anti-inflammatory, and anti-apoptotic capabilities.

Response to "Nephrotoxicity: Evidence in Patients Receiving Cisplatin Therapy"

An article by Duffy, Fitzgerald, Boyle, and Rohatgi (2018) was published in the April issue of the Clinical Journal of Oncology Nursing. Based on review, the authors suggested some clinical recommendations to protect the kidneys against cisplatin-induced nephrotoxicity, including hydration or supplementation of magnesium or mannitol during cisplatin administration. In addition to clinical findings, the related basic sciences data may be helpful in formulating treatment guidelines in cisplatin therapy. This letter will present several suggestions for future clinical studies based on laboratory findings.

The Effects of Magnesium and Zinc Co-Supplementation on Biomarkers of Inflammation and Oxidative Stress, and Gene Expression Related to Inflammation in Polycystic Ovary Syndrome: a Randomized Controlled Clinical Trial

Magnesium and zinc are known to exert multiple beneficial effects including anti-inflammatory and antioxidant actions. To our knowledge, data on the effects of magnesium and zinc co-supplementation on biomarkers of inflammation and oxidative stress and gene expression related to inflammation in subjects of polycystic ovary syndrome (PCOS) are scarce. This study was conducted to evaluate the effects of magnesium and zinc co-supplementation on biomarkers of inflammation and oxidative stress and gene expression related to inflammation in subjects with PCOS. This randomized double-blind, placebo-controlled trial was conducted among 60 subjects with PCOS diagnosed according to the Rotterdam criteria, aged 18-40 years old. Participants were randomly assigned into two groups to take either 250 mg of magnesium oxide plus 220 mg of zinc sulfate (containing 50 mg zinc) supplements (n = 30) or placebo (n = 30) twice a day for 12 weeks. Biomarkers of inflammation and oxidative stress were assessed at baseline and at end of treatment. Gene expression related to inflammatory cytokines was assessed in peripheral blood mononuclear cells (PBMCs) of PCOS women with RT-PCR method. After the 12-week intervention, compared with the placebo, magnesium and zinc co-supplementation significantly decreased serum high-sensitivity C-reactive protein (hs-CRP) (- 1.6 ± 2.4 vs. + 0.1 ± 0.7 mg/L, P = 0.001) and protein carbonyl (PCO) (- 0.14 ± 0.28 vs. + 0.02 ± 0.07 mmol/mg protein, P = 0.002) and significantly increased plasma total antioxidant capacity (TAC) levels (+ 60.7 ± 69.4 vs. - 1.5 ± 141.5 mmol/L, P = 0.03). Results of RT-PCR demonstrated that compared with the placebo, magnesium and zinc co-supplementation downregulated gene expression of interleukin-1 (IL-1) (P = 0.007) and tumor necrosis factor alpha (TNF-α) (P = 0.03) in PBMCs of subjects with PCOS. Overall, magnesium and zinc co-supplementation, compared with the placebo, for 12 weeks among PCOS women had beneficial effects on serum hs-CRP, plasma PCO, TAC, and gene expression of IL-1 and TNF-α.

CLINICAL TRIAL REGISTRATION NUMBER

http://www.irct.ir : IRCT201706075623N121.

Magnesium Supplementation and the Effects on Wound Healing and Metabolic Status in Patients with Diabetic Foot Ulcer: a Randomized, Double-Blind, Placebo-Controlled Trial

Hypomagnesemia is associated with the development of neuropathy and abnormal platelet activity, both of which are risk factors for diabetic foot ulcer (DFU). This study was carried out to evaluate the effects of magnesium administration on wound healing and metabolic status in subjects with DFU. This randomized, double-blind, placebo-controlled trial was performed among 70 subjects with grade 3 DFU. Subjects were randomly divided into two groups (35 subjects each group) to receive either 250 mg magnesium oxide supplements or placebo daily for 12 weeks. Pre- and post-intervention wound depth and appearance were scored in accordance with the "Wagner-Meggitt's" wound assessment tool. Fasting blood samples were taken at baseline and after the 12-week intervention to assess related markers. After the 12-week treatment, compared with the placebo, magnesium supplementation resulted in a significant increase in serum magnesium (+0.3 ± 0.3 vs. -0.1 ± 0.2 mg/dL, P < 0.001) and significant reductions in ulcer length (-1.8 ± 2.0 vs. -0.9 ± 1.1 cm, P = 0.01), width (-1.6 ± 2.0 vs. -0.8 ± 0.9 cm, P = 0.02), and depth (-0.8 ± 0.8 vs. -0.3 ± 0.5 cm, P = 0.003). In addition, significant reductions in fasting plasma glucose (-45.4 ± 82.6 vs. -10.6 ± 53.7 mg/dL, P = 0.04), serum insulin values (-2.4 ± 5.6 vs. +1.5 ± 9.6 μIU/mL, P = 0.04), and HbA1c (-0.7 ± 1.5 vs. -0.1 ± 0.4%, P = 0.03) and a significant rise in the quantitative insulin sensitivity check index (+0.01 ± 0.01 vs. -0.004 ± 0.02, P = 0.01) were seen following supplementation of magnesium compared with the placebo. Additionally, compared with the placebo, taking magnesium resulted in significant decrease in serum high-sensitivity C-reactive protein (hs-CRP) (-19.6 ± 32.5 vs. -4.8 ± 11.2 mg/L, P = 0.01) and significant increase in plasma total antioxidant capacity (TAC) concentrations (+6.4 ± 65.2 vs. -129.9 ± 208.3 mmol/L, P < 0.001). Overall, magnesium supplementation for 12 weeks among subjects with DFU had beneficial effects on parameters of ulcer size, glucose metabolism, serum hs-CRP, and plasma TAC levels.

CLINICAL TRIAL REGISTRATION NUMBER

http://www.irct.ir : IRCT201612225623N96.

The Role of Gamma Amino Butyric Acid in Cisplatin-induced Nephrotoxicity in Streptozotocin-induced Diabetic Rats

Background:

Diabetes mellitus can change the risk of developing cancer. Cisplatin (CP) is a common antineoplastic drug. The major side effect of CP is nephrotoxicity. Gamma amino butyric acid (GABA) is an antioxidant agent that may have a protective role against CP-induced nephrotoxicity. The aim of the present study was to investigate the role of GABA in CP-induced nephrotoxicity in hyperglycemic male and female rats.

Materials and Methods:

Sixty male and female Wistar diabetic rats were used in ten experimental groups. GABA alone groups received GABA (50 μmol/kg/d i.p.) for 12 days. CP alone groups received CP (2.5 mg/kg/d i.p.) for 6 days. Other groups received GABA in the form of therapy (T) + CP, prophylaxis (P) + CP, and prophylaxis-treatment (PT) + CP. Finally, blood samples were obtained, and animals were killed for kidney tissue investigation.

Results:

In female rats, the serum levels of creatinine (Cr) did not change by GABA rather than CP and also there were no significant changes in blood urea nitrogen to creatinine ratio (BUN/Cr). In male rats, plasma Cr level increased by GABA (P) and (T). Body weight loss was significantly different among groups (P < 0.05). BUN/Cr ratio significantly increased in CP and GABA (PT) + CP groups. In two genders, plasma Cr level significantly decreased in CP groups (P < 0.05). The kidney levels of malondialdehyde enhanced significantly in CP groups.

Conclusion:

Hyperglycemia has protective effect against CP-induced nephrotoxicity. GABA did not change this effect in female, but in male in the form of PT, GABA maintained it.

The Protective Effect of L-arginine in Cisplatin-induced Nephrotoxicity in Streptozotocin-induced Diabetic Rats

Background:

Cisplatin (CP) is accompanied with a nephrotoxicity. L-arginine (LA) plays an important role in the regulation of renal function. The present study was designed to investigate the protective role of LA supplementation in CP-induced nephrotoxicity in a diabetic rat's model.

Materials and Methods:

Sixteen adult female and male Wistar rats were used and they received a single dose of streptozotocin (STZ) (60 mg/kg i.p.). Diabetic female and male rats were arranged as groups 1–5 and groups 6–10, respectively. Groups 1 and 6 (LA groups) received LA alone. Groups 2 and 7 (CP groups) received CP alone. Groups 3 and 8 (CP + LA [PT] groups) received LA as prophylaxis and then treated with LA and CP. Groups 4 and 9 (CP + LA [T] groups) were treated with LA and CP simultaneously. Groups 5 and 10 (CP + LA [P] groups) received LA as prophylaxis and then treated with CP.

Results:

The serum creatinine (Cr) level of males in Groups 8 and 9 was significantly increased when compared with LA and CP (P < 0.05), whereas no differences were observed in Cr level in female groups. Blood urea nitrogen/Cr ratio and kidney weight were reduced in all CP-receiving male rats. Such observation was not seen in female rats. Different results related to weight loss were obtained between male and female animals. The kidney tissue damage score in CP + LA (PT) male group was significantly greater than CP group (P < 0.05).

Conclusion:

Our findings indicate that administration of LA in female and male rats has no protective effect on the severity of nephrotoxicity induced by CP in diabetic rats.

Magnesium attenuates cisplatin-induced nephrotoxicity by regulating the expression of renal transporters

Cisplatin (CDDP)-induced nephrotoxicity (CIN) is one of the most serious toxicities caused by this potent antitumor agent. It has been reported that Mg premedication attenuates CIN in clinical trials; however, the mechanism underlying its nephroprotection is not fully understood. Therefore, the aim of this study was to determine whether Mg administration affects CDDP accumulation by regulating the expression level of renal transporters. Rats were divided into control, Mg (40mg/kg) alone, 2.5mg/kg CDDP with (20 and 40mg/kg) and without Mg, 5mg/kg CDDP groups. These substances were administered on the same day and 7 days later their kidneys were removed. The expression levels of renal transporters and platinum (Pt) accumulation were analyzed. The serum creatinine level was significantly increased by CDDP administration and treatment with Mg significantly ameliorated such elevation. The expressions of the renal organic cation transporter 2 (rOct2) and renal multidrug and toxin extrusion protein 1 (rMate1) were downregulated and upregulated, respectively following co-administration with Mg, which significantly reduced the renal Pt accumulation in the 2.5mg/kg CDDP-treated group. Moreover, Mg dose-dependently downregulated rOct2, not affecting rMate expression, resulting in the attenuation of CIN. Mg co-administration protected the downregulation of the transient receptor potential subfamily Melastatin 6 (rTrpm6), but not the epidermal growth factor (rEgf), as a result, Mg co-injection attenuated CDDP-induced hypomagnesemia. In conclusion, Mg co-administration reduced Pt accumulation by regulating the expression of the renal transporters, rOct2 and rMate1 and, thereby, attenuated CIN.

Cisplatin-Induced Nephrotoxicity; Protective Supplements and Gender Differences

Cisplatin (CDDP) has been widely used as a chemotherapeutic agent for solid tumors. The most common side effect of CDDP is nephrotoxicity, and many efforts have been made in the laboratory and the clinic to employ candidate adjuvants to CDDP to minimize this adverse influence. Many synthetic and herbal antioxidants as well as trace elements have been investigated for this purpose in recent years and a variety of positive and negative results have been yielded. However, no definitive supplement has so far been proposed to prevent CDDP-induced nephrotoxicity; however, this condition is gender related and the sex hormone estrogen may protect the kidney against CDDP damage. In this review, the results of research related to the effect of different synthetic and herbal antioxidants supplements are presented and discussed with suggestions included for future work.

Effect of enalapril in cisplatin-induced nephrotoxicity in rats; gender-related difference

Background:

The function of renin angiotensin system (RAS) is gender-related, and this system affects cisplatin (CP)-induced nephrotoxicity. In this study, we compared the effect of enalapril as an angiotensin-converting enzyme (ACE) inhibitor on CP-induced nephrotoxicity between male and female rats.

Materials and Methods:

Sixty-two adult male and female Wistar rats were divided into eight groups. Both genders received CP (2.5 mg/kg, i.p.) and enalapril (30 mg/kg, i.p.) for 7 days in compared with CP alone or enalapril alone or vehicle alone treated groups. At the end of the experiment, blood samples were obtained, and the kidney tissue was investigated for histopathological changes.

Results:

CP increased the serum levels of blood urea nitrogen and creatinine as well as kidney weight and kidney tissue damage score in both genders (P < 0.05). However, not only enalapril failed to ameliorate the aforementioned parameters in both genders, but also it intensified nephrotoxicity in females (P < 0.05). In addition, enalapril enhanced body weight loss induced by CP in females (P < 0.05). CP alone decreased kidney level of nitrite in both genders (P < 0.05) and enalapril could not reverse this decreasing. The combination of enalapril and CP significantly increased serum level of nitrite in females, but this was not observed in males (P < 0.05).

Conclusion:

Enalapril as an ACE inhibitor failed to ameliorate nephrotoxicity induced by CP in both male and female rats. In addition, enalapril aggravated CP-induced nephrotoxicity in female possibly due to gender-dependent RAS response.

Magnesium sulphate can prolong pregnancy in patients with severe early-onset preeclampsia

OBJECTIVE

To assess whether long-term use of magnesium sulphate prolongs pregnancy in patients with severe early-onset preeclampsia.

METHODS

Retrospective cohort study included all singleton pregnancies with severe early-onset preeclampsia, expectantly managed in our institution between 2005 and 2013. Obstetric and perinatal outcomes were compared between patients managed using a current protocol that tolerates long-term (over 48 h) use of magnesium sulphate (long-term group, n = 26) and a historical control group (control group, n = 15) that underwent conventional treatment (up to 48 h use of magnesium sulphate).

RESULTS

Long-term group showed significant prolongation of pregnancy compared with the control group (9.2 ± 7.9 versus 16.6 ± 9.3 d, log-rank test, p = 0.021), which was also observed in patients with severe preeclampsia occurring before 28 weeks' gestation (n = 11, 4.5 ± 5.2 versus 13.2 ± 6.8 d, log-rank test, p = 0.035). In contrast to a progressive decrease of platelet count in patients managed without magnesium sulphate, administration of magnesium sulphate for 7 d prevented the decrease of platelet count (p = 0.001). Thirty two percent of patients (13/41) experienced a major complication irrespective of duration of magnesium sulphate use.

CONCLUSIONS

Long-term use of magnesium sulphate prolonged pregnancy in patients with severe early-onset preeclampsia and can help alleviate progression of preeclampsia.

Role of endothelin-1 antagonist; bosentan, against cisplatin-induced nephrotoxicity in male and female rats

BACKGROUND

Cisplatin (CP) is a chemotherapy drug, with the major side effect of nephrotoxicity. The level of endothelin-1 (ET-1) increases during nephrotoxicity, which is accompanied with vasoconstrictive properties. Bosentan (BOS) is a nonselective ET-1 receptor antagonist, having vasodilatory and anti-hypertension effects. The purpose of this study was to investigate the renoprotective effect of BOS against CP-induced nephrotoxicity in male and female rats.

MATERIALS AND METHODS

Male and female rats were divided into six groups; groups 1-3 and 4-6 were male and female rats, respectively. Animals in groups 1 and 4 were considered as negative control and groups 2 and 5 considered as positive control groups received BOS (30 mg/kg/day) alone and CP (2.5 mg/kg/day) alone, respectively, for 1-week. The animals in groups 3 and 6 were treated with both CP and BOS. Finally, serum parameters were measured, and the kidney tissue was subjected to staining to evaluate tissue damage.

RESULTS

The serum levels of blood urea nitrogen and creatinine, kidney tissue damage score and kidney weight elevated, and body weight significantly decreased in both CP alone and in CP plus BOS-treated groups when compared with the control groups (P < 0.05), while BOS did not ameliorate these parameters neither in males nor in females. No significant differences were observed in serum levels of nitrite and malondialdehyde between the groups, but kidney tissue level of nitrite decreased significantly in CP alone and CP plus BOS-treated groups (P < 0.05).

CONCLUSION

Renoprotective effect of BOS, as ET-1 blocker, was not observed against CP-induced nephrotoxicity neither in male nor in female rats. This is while BOS promoted the severity of injuries in females.

Effect of testosterone on Cisplatin-induced nephrotoxicity in surgically castrated rats

BACKGROUND

Cisplatin (CP) is an important antitumor drug with serious side effects such as nephrotoxicity. Estrogens can affect CP-induced nephrotoxicity; however, the role of testosterone (TS), the main male sex hormone, is not clear.

OBJECTIVES

This study aimed to investigate the effect of TS on CP-induced nephrotoxicity in castrated male rats.

MATERIALS AND METHODS

A total of 54 male Wistar rats were castrated and allocated into eight groups. Groups 1 through 3 respectively received 10, 50, and 100 mg/kg/wk of TS and group 4 received sesame oil for four weeks; then all four groups received 2.5 mg/kg/d CP for one week. Groups 5 through 8 received the same treatment regimen as groups 1 through 4 during first four weeks but instead of CP, they received saline for one week. Then the animals were sacrificed for biochemical and histopathologic studies.

RESULTS

CP increased the serum levels of blood urea nitrogen (BUN), creatinine (Cr), and malondialdehyde (SMDA) as well as kidney weight (KW), bodyweight (BW) loss, and kidney tissue damage score (KTDS). It significantly decreased the serum and kidney levels of nitrite and serum level of TS in comparison with the control group (P < 0.05). However, coadministration of CP and low dose of TS significantly decreased the serum levels of BUN as well as Cr and KTDS (P < 0.05). Administration of high-dose TS alone increased the SMDA level, KTDS, and KW while decreased the BW significantly (P < 0.05).

CONCLUSIONS

It seems that testosterone in low dose, i.e. physiologic dose, protects kidneys against CP-induced nephrotoxicity; however, special care is needed in CP therapy of patients with high levels of TS.

Effects of pretreatment with single-dose or intermittent oxygen on Cisplatin-induced nephrotoxicity in rats

Background:

Renal injury is the main side effect of cisplatin (CP), an anticancer drug. It has been shown that pretreatment with single-dose oxygen (0.5 to six hours) could reduce CP-induced renal toxicity in rats.

Objectives:

The present study aimed to compare the effects of pretreatment with single-dose and intermittent O₂ on CP-induced nephrotoxicity.

Materials and Methods:

Adult male rats were allocated to seven groups (eight rats in each group). The rats were kept in normal air or hyperoxic environment (O₂, 80%) for either a single six-hour period or intermittent six hours per day for seven days and then were subjected to intraperitoneal injection of saline or CP (5 mg/kg) at 48 hours, 72 hours, or seven days after exposure to O₂. Three days after CP (or Saline) injection, renal function tests, renal tissue injury scores, and cleaved Caspase-3 and Bax/Bcl-2 genes expression (as markers of renal cell apoptosis) were assessed.

Results:

Treatment with the 6-hour single-dose O₂ reduced renal injury significantly when CP was administrated 48 hours after O₂ pretreatment. Pretreatment with intermittent seven days of six hours per day had no protective effects and even relatively worsened renal injury when CP was injected 48 hours or 72 hours after the last session of O₂ pretreatment. The beneficial effects of pretreatment with O₂ on renal structure and function were seen if CP was administrates seven days after pretreatment with intermittent O₂.

Conclusions:

The pattern of pretreatment with O₂ could change this potential and highly protective strategy against CP-induced nephropathy to an ineffective or even mildly deteriorating one. Therefore, O₂ administration before CP injection to patients with cancer, for therapeutic purposes or as a preconditioning approach, should be performed and investigated with caution until exact effects of different protocols has been determined in human.