Renal vascular response to angiotensin 1-7 in rats: the role of Mas receptor.

Recently a cross talk between angiotensin 1-7 (Ang1-7) receptor (MasR) and angiotensin II receptors types 1 and 2 (AT1R and AT2R) has been highlighted. The effects of MasR antagonist (A779) compared to the vehicle on the renal blood flow (RBF) and renal vascular resistance (RVR) responses to Ang1-7 (300 ng/kg/min) infusion in the absence of Ang II receptors in male and female rats were determined at controlled renal perfusion pressure. Ang1-7 infusion did not alter mean arterial pressure in male and female rats. However, A779 compared to vehicle increased RBF (18% vs 3%) and decreased RVR (13% vs 4%) responses to Ang1-7 infusion significantly (P < 0.05) in male when AngII receptors were blocked. Such observation was not occurred in female animals. Finally it was concluded that renal vascular responses to Ang1-7 administration may not be exerted by MasR in male rats, and these responses are not mediated with AngII receptors.

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.

Protective effect of pomegranate flower extract against gentamicin-induced renal toxicity in male rats.

INTRODUCTION: Gentamicin (GM) as an antibiotic is used in clinic. However, its administration is limited by side effects such as nephrotoxicity. Herbal extracts could be used in therapeutic approaches. OBJECTIVES: The present study was planned to investigate whether pomegranate flower extract (PFE) could ameliorate GM-induced renal toxicity in male rats. MATERIALS AND METHODS: Twenty eight male Wistar rats were divided into 5 groups. Groups 1 and 2 respectively received PFE 25 and 50 mg/kg for 9 days. Groups 3, 4 and 5 received saline, PFE 25 mg/kg, and PFE 50 mg/kg for 9 days, respectively, and GM (100 mg/kg/day) was administered from day 3 on. Blood samples were obtained, and after sacrificing the animals, the kidneys were removed for histopathology investigations. RESULTS: GM alone increased the serum levels of creatinine (Cr) and blood urea nitrogen (BUN), and tissue damage and kidney weight (P < 0.05). However, administration of low dose of PFE accompanied with GM decreased these markers significantly (P < 0.05). Low dose of PFE also ameliorated weight loss induced by GM (P < 0.05). CONCLUSION: It is concluded that PFE 25 mg/kg is the effective dose to ameliorate nephrotoxicity induced by GM.

Lack of nephroprotective efficacy of althaea officinalis flower extract against gentamicin renal toxicity in male rats.

BACKGROUND: Gentamicin (GM) is used as antibiotic for Gram-negative infections, but its administration is limited due to a side-effect of nephrotoxicity. It was attempted to investigate the effect of Althaea officinalis flower extract (AOFE) against nephrotoxicity induced by GM in male rats. METHODS: 30-year-old male Wistar rats were divided into five groups. Group 1 as a negative control group received AOFE 250 mg/kg/day. Groups 2-5 received saline, AOFE 50 mg/kg/day, AOFE 250 mg/kg/day, and AOFE 500 mg/kg/day for 9 days, respectively, and GM (100 mg/kg/day) was added from the 3(rd) day on. At the end of the experiment, blood samples were obtained, animals were sacrificed, and the kidneys were removed immediately. RESULTS: Gentamicin (in group 2) significantly increased serum levels of blood urea nitrogen and creatinine as well as the pathological damage score (P < 0.05) when compared with group 1. Low dose of AOFE did not decrease the nephrotoxicity induced by GM while the high dose of AOFE aggravated renal toxicity (P < 0.05). CONCLUSIONS: Although AOFE acts as an antioxidant, at the doses used in the current study did not ameliorate nephrotoxicity induced by GM.

Vitamin e is a nephroprotectant agent in male but not in female in a model of Cisplatin-induced nephrotoxicity.

Background. The role of gender for nephroprotectant agent such as vitamin E in cisplatin- (CP-) induced nephrotoxicity has not been documented yet. Methods. One group from each gender of Wistar rats received a single dose of CP (7 mg/kg; i.p) and was treated with vitamin E (1 g/kg/day) for 7 days, and they were compared with similar gender in the control group. Results. The serum levels of blood urea nitrogen (BUN) and creatinine (Cr) in male animals treated with CP was not different from the control group, but it was significantly different in the female rats (P < 0.05). The CP-induced damage intensity in male kidney tissue was not significantly different between the CP-treated and control groups, but this was not the case in female, indicating that the tissue damage in female is significantly different from the control group (P < 0.05). No significant difference in serum levels of magnesium (Mg), nitrite, malondialdehyde (MDA), and lactate dehydrogenase (LDH) was seen between the genders. Kidney weight and body weight changes were statistically significant in both genders (P < 0.05). Significant difference was observed in uterus weight between the two groups of female (P < 0.05). Conclusion. Vitamin E may prevent CP-induced nephrotoxicity in male, but possibly it has not such nephroprotectant effect in female.

Sex differences in protective effect of recombinant human erythropoietin against cisplatin-induced nephrotoxicity in rats.

INTRODUCTION: The protective role of recombinant human erythropoietin (RHE) against cisplatin-induced nephrotoxicity has been reported, but the role of sex differences is not clearly known. The aim of this study was to determine the sex-based difference in the protective effect of RHE against cisplatin-induced nephrotoxicity. MATERIALS AND METHODS: Thirty-three Wistar rats were divided into 6 groups. According to protocol l, male and female rats were treated with RHE (100 IU/kg/d) for 3 days and then received a single dose of cisplatin (7 mg/kg). According to protocol 2, the rats received the same single dose of cisplatin and then were treated with RHE for 7 days. Two other groups of male and female rats received a similar regimen of protocol 2 except for saline instead of RHE. All the animals were sacrificed 1 week after cisplatin administration. RESULTS: All of the experimental animals experienced weight loss. The percentage change of weight in male rats with protocol 1 was significantly less than that in male rats in protocol 2 and control groups. However, in female groups, the percentage of change in weights was slightly higher with protocol 2 than with protocol 1 and control treatment. Administration of RHE significantly decreased changes in serum creatinine, BUN, and malondialdehyde levels in male rats, but not in females. No significant difference was observed in serum nitrite level, kidney weight, and kidney damage score between the groups. CONCLUSIONS: This study suggested that erythropoietin may lead to different responses against cisplatin-induced nephrotoxicity in male and female rats.

N-acetylcysteine Prevents Kidney and Lung Disturbances in Renal Ischemia/Reperfusion Injury in Rat.

BACKGROUND: One of the most common causes of acute kidney injury (AKI) is kidney ischemia/reperfusion injury (IRI). The distant organ injury such as acute lung injury is one of the side effects of AKI or kidney IRI. In this study, we performed bilateral renal IRI in rats and the protective role of N-acetylcysteine (NAC) in kidney and lung was investigated. METHODS: Rats (n = 30) were randomly assigned to four experiment groups. The group 1 was assigned as sham-operated group. Before kidney IRI performance, the others groups were treated with saline (group 2), 150 mg/kg (group 3) or 500 mg/kg (group 4) of NAC, and the treatment were continued daily after IRI for next 3 days. At day 3, the all groups' animals were subjected for the measurements. RESULTS: The serum level of blood urea nitrogen (BUN) and creatinine (Cr) in the control group increased significantly (P < 0.05), and administration of NAC (150 mg/kg) decreased the serum levels of Cr and BUN. However, only the serum level of Cr decreased significantly (P < 0.05). NAC did not improve kidney weight and damage; however, its low dose (150 mg/kg) attenuated the lung injury score (P < 0.05) when compared with the control group. No significant differences were observed in lung water content and endothelial permeability, serum levels of malondialdehyde and nitrite between the groups. CONCLUSIONS: Low dose of NAC as a protectant agent may protect the kidney function and lung tissue damage after kidney IRI.

Inhibition of Nitric Oxide Synthase by L-NAME Promotes Cisplatin-Induced Nephrotoxicity in Male Rats.

Objective. Nitric oxide (NO) has numerous important functions in the kidney. The role of NO in cisplatin (CP)-induced nephrotoxicity is not completely understood. This study was designed to determine the role of NO synthase inhibitor (L-NAME) on the severity of CP-induced nephrotoxicity in rats. Methods. Sixty four male (M) and female (F) Wistar rats were randomly divided into eight groups. The sham groups (group 1, male, n = 6 and group 2, female, n = 6) received saline. Groups 3 (male, n = 8) and 4 (female, n = 8) were treated with L-NAME (4 mg/kg, i.p.), and groups 5 (male, n = 8) and 6 (female, n = 8) received CP (3 mg/kg) for 7 days. Groups 7 (male, n = 8) and 8 (female, n = 8) were treated with L-NAME and CP for 7 days. Results. The CP-alone treated rats showed weight loss and increase in serum levels of blood urea nitrogen (BUN) and creatinine (Cr). Coadministration of L-NAME and CP did not improve weight loss, and it increased the levels of BUN and Cr in male but not in female rats (P < 0.05). CP alone increased kidney damage significantly (P < 0.05 ), however, the damage induced by combination of CP and L-NAME was gender-related. Conclusion. NOS inhibition by L-NAME increased CP-induced nephrotoxicity, which was gender-related.

Vitamin E, Vitamin C, or Losartan Is Not Nephroprotectant against Cisplatin-Induced Nephrotoxicity in Presence of Estrogen in Ovariectomized Rat Model.

Background. The nephroprotective effect of vitamins E and C or losartan against cisplatin (CP)- induced nephrotoxicity when they are accompanied by estrogen was investigated. Methods. The ovariectomized rats received estradiol valerate for two weeks. At the end of the first week, a single dose of CP (7 mg/kg, IP) was also administered, and they received placebo (group 1), vitamin E (group 2), vitamin C (group 3), or losartan (group 4) every day during the second week, and they were compared with another three control groups. Results. CP alone increased the serum levels of blood urea nitrogen (BUN), creatinine (Cr), and kidney tissue damage score (KTDS), significantly (P < 0.05), however at the presence of estradiol and CP, vitamin C, vitamin E, or losartan not only did not decrease these parameters, but also increased them significantly (P < 0.05). The serum level of superoxidase dismutase (SOD) was reduced by CP (P < 0.05), but it was increased when estradiol or estradiol plus vitamin C or losartan were added (P < 0.05). Conclusion. The particular pharmacological dose of estrogen used in this study abolish the nephroprotective effects vitamins C and E or losartan against CP-induced nephrotoxicity.

Estrogen Abolishes Protective Effect of Erythropoietin against Cisplatin-Induced Nephrotoxicity in Ovariectomized Rats.

Introduction. Nephrotoxicity is one the side effect of cisplatin therapy and erythropoietin has been candidate as a nephroprotectant agent. However, its nephroprotective effect when it is accompained with estrogen has not been studied in female. Methods. 27 ovariectomized female Wistar rats divided into five groups. Groups 1 & 2 received estradiol valerate (0.5 mg/kg/week) for four weeks, and single dose of cisplatin (7 mg/kg, ip) was administrated at the end of week 3. Then the group 1 was treated with erythropoietin (100 U/kg/day), and the group 2 received vehicle during week 4. Groups 3 and 4 were treated similar to group 1 and 2, except for placebo instead estradiol valerate. Group5 (negative control) received placebo during the study. Animals were killed at the end of week 4. Results. In non-erythropoietin treated rats, cisplatin significantly increased the serum levels of blood urea nitrogen and creatinine (P < 0.05). However, these biomarkers significantly decreased by erythropoietin (P < 0.05). The weight loss, kidney weight, and kidney tissue damage score in rats treated with cisplatin but without estradiol were significantly less than the values in similar group when estradiol was present (P < 0.05). Conclusion. It seems that erythropoietin could protect the kidney against cisplatin-induced nephrotoxicity. This protective effect was not observed when estrogen was present.