Vitamin B6 dose-dependently ameliorates renal hemodynamic toxicity of cisplatin in rat model of nephrotoxicity: the histopathologic and biochemical findings

Despite its significant anticancer activity, the clinical use of cisplatin is often limited by its undesirable side effects in the kidney known as nephrotoxicity. It is a common and often overlooked clinical entity that presents itself in the setting of oxidative stress-associated diseases in older individuals with renal failure. In this study, we investigated the antioxidant-protecting effects of vitamin B₆ in the kidney, with a view on the vasoregulatory role of renal pyridoxal 5′-phosphate at reducing the hemodynamic toxicity of cisplatin. Hence, 50 male Sprague–Dawley rats were randomly assigned in one of five groups of the study to receive a corresponding dose of either normal saline, vitamin B₆ (200 mg/kg/bw; i.m.) or cisplatin alone (7 mg/kg/bw; i.m.), or in combination with vitamin B₆ at low (100 mg/kg/bw; i.m.) and high dose (200 mg/kg/bw; i.m.) for 10 days as animal model of renal failure. Daily administration of cisplatin at a dose of 7 mg/kg/bw resulted in a significant increase in local and systemic oxidative stress of the kidney and a decrease in glomerular function as a result of early hemodynamic toxicity. Histopathological examinations of renal tissues revealed acute tubular necrosis with hyaline cast formation triggered by cisplatin over 9 days of the study, in addition to interstitial nephritis and tubular epithelial loss. Further biochemical studies in HVB group showed the protecting effects of supplemented vitamin B₆ at a high dose, including a slowdown in urinary enzyme activity, a significant decrease in plasma lipid peroxidation, and an increased tissue superoxide dismutase activity with recovery in the glomerular hemodynamicity and ATPase activity up to 50 % when compared to the low-dose rats and controls. In high-dose animals, the normal glomerular and tubular function on recovery from toxic renal failure led us to conclude that the antioxidant property of vitamin B₆ consistently increases with the dose intensity. The present study also provided evidence that high dose of vitamin B₆ prevented both functional and histological renal changes induced by cisplatin in rats, more efficient than low dose of the vitamin.     

Dose-related protecting effects of vitamin C in gentamicin-induced rat nephrotoxicity: a histopathologic and biochemical study

Gentamicin remains the mainstay in treatment of gram-negative infections, despite its potential ototoxicity and nephrotoxicity. In this study, we investigated dose-related protecting effects of vitamin C against gentamicin-induced rat nephrotoxicity. Hence, 50 male albino Wistar rats were randomly divided into five equal groups to receive a corresponding dose of either normal saline as control, vitamin C (200 mg/kg/bw, i.m.) or gentamicin alone (80 mg/kg/bw, i.m.) or in combination with vitamin C at low dose (200 mg/kg/bw, i.m.; LVG) and high dose (600 mg/kg/bw, i.m.) for 9 days. Daily administration of gentamicin at a dose of 80 mg/kg resulted in a significant increase in oxidative stress in renal tissues and plasma and a concomitant decrease in the creatinine clearance and renal blood flow as result of early hemodynamic toxicity. Histopathological examinations revealed acute tubular necrosis with hyaline cast formation triggered by gentamicin over 9 days of experiment, in addition to interstitial nephritis and tubular epithelial loss. Further biochemical studies showed protecting effects of supplemented vitamin C at a high dose, including slowdown in the urinary enzyme activity, a significant decrease in plasma lipid peroxidation, and an increased tissue superoxide dismutase activity with recovery in the glomerular hemodynamicity and the ATPase activity up to 50% when compared to controls and low-dose rats (LVG). In high-dose animals, normal glomerular and tubular function on recovery from toxic renal failure led us to conclude that antioxidant properties of vitamin C consistently increase with dose intensity. The present study also provided evidence that high dose of vitamin C prevented both functional and histological renal changes induced by gentamicin in rats, more efficient than low dose of the vitamin.     

Antioxidant protecting effects of vitamin B6 at reducing hemodynamic toxicity of gentamicin in rat model of nephrotoxicity

Routine therapeutic use of gentamicin in patients with preexisting renal failure may confront us with the toxic effects of aminoglycosides in the kidney known as nephrotoxicity. It is a common and often overlooked clinical entity that presents itself in the setting of oxidative stress-associated diseases in older individuals with renal failure. In this study, we investigated the antioxidant protecting effects of vitamin B₆ in the kidney, with a view on vasoregulatory role of renal pyridoxal 5′-phosphate at reducing the hemodynamic toxicity of gentamicin. Hence, 50 male Sprague–Dawley rats were randomly assigned in five groups to receive a corresponding dose of either normal saline, vitamin B₆ (100 mg/kg/bw; i.m.) or gentamicin alone (80 mg/kg/bw; i.m.), or in combination with vitamin B₆ at low (100 mg/kg/bw; i.m.) and high dose (200 mg/kg/bw; i.m.) for 10 days as animal model of nephrotoxicity. Daily administration of gentamicin at a dose of 80 mg/kg resulted in a significant increase in local and systemic oxidative stress and a decrease in glomerular functions as result of early hemodynamic toxicity. Histopathological examinations of renal tissues revealed acute tubular necrosis with hyaline cast formation triggered by gentamicin over 9 days of the experiment, in addition to interstitial nephritis and tubular epithelial loss. Further biochemical studies in HVB group showed the protecting effects of supplemented vitamin B₆ at a high dose, including a slowdown in urinary enzyme activity, a significant decrease in plasma lipid peroxidation, and an increased tissue superoxide dismutase activity with recovery in the glomerular hemodynamicity and ATPase activity up to 50 % when compared to low-dose rats and controls. In high-dose animals, normal glomerular and tubular function on recovery from toxic renal failure led us to conclude that antioxidant properties of vitamin B₆ consistently increase with dose intensity. The present study also provided evidence that high dose of vitamin B₆ prevented both functional and histological renal changes induced by gentamicin in rats, more efficient than low dose of the vitamin.     

Effect of metformin against cisplatin induced acute renal injury in rats: A biochemical and histoarchitectural evaluation

Although cisplatin has been a mainstay for cancer therapy, its use is limited mainly because of nephrotoxicity. Accumulating literature suggest the antioxidant and cytoprotective effect of metformin, a first line antidiabetic drug. With this background, we investigated the effect of metformin on the cisplatin induced nephrotoxicity in rats. A single injection of cisplatin (7.5 mg/kg, i.p.) caused marked renal damage, characterized by a significant increase in blood urea nitrogen (BUN), serum creatinine (Cr) and abnormal histo-architecture of kidney. These were accompanied by significant elevation of malondialdehyde (MDA), total reactive oxygen species (tROS) and caspase-3 levels and decreased antioxidant levels. Metformin treatment significantly attenuated the increase in malondialdehyde and tROS generation and restores the decrease in both enzymatic and non-enzymatic antioxidants. However metformin treatment did not prevent the cisplatin induced renal injury as there was no significant difference of renal function parameters (BUN and Cr), kidney histopathology as well as caspase-3 activity between cisplatin per se and metformin plus cisplatin treated rats. Histopathology studies revealed that similar glomerular and tubular pathological architecture in both cisplatin per se and cisplatin plus metformin group. In conclusion, the present study demonstrated that metformin is not an adjuvant drug to treat nephrotoxicity associated with cisplatin therapy.     

Co-supplementation of single and multi doses of vitamins C and E ameliorates cisplatin-induced acute renal failure in mice

Higher doses of antioxidant vitamins C and E have been proved to be effective against cisplatin-induced nephrotoxicity in animals. However, the possible effective equivalent dose in human was found to be higher than that of the upper tolerable intake level (UL) for these vitamins. Hence, the current study was aimed to evaluate the protective effect of co-supplementation of single and multi doses of vitamins C and E against cisplatin-induced acute renal failure in mice. Single dose of vitamin C (500 mg/kg), vitamin E (500 mg/kg), and vitamin C plus vitamin E (250 mg/kg each) were administered orally 1 h prior to cisplatin (12 mg/kg, i.p) injection, whereas in a multidose study they were administered 1 h prior, and 24 and 48 h after the cisplatin injection. Serum urea and creatinine levels were estimated 72 h after the injection of cisplatin. Renal concentrations of glutathione (GSH) and malondialdehyde (MDA) were also determined. Co-supplementation of vitamins significantly protected the cisplatin-induced increased levels of serum urea, creatinine, renal MDA, and the declined renal GSH level. Administration of single and multi doses of vitamin C plus E (250 mg/kg each) rendered significant nephroprotection. Therefore, accounting for the rare side effect from high intake of vitamins C and E observation of this study indicates that a multidose combination therapy of these vitamins at their lower doses can be effective in protecting the cisplatin-induced renal damage. The protection is partially mediated through the antioxidant effect of the vitamins.     

Effects of selenium pretreatment on cisplatin-induced chromosome aberrations in wistar rats

Selenium is an essential trace element and a potent anticancer agent. Extensive laboratory studies demonstrate that selenium is an effective chemopreventive agent in various sites in animals. The administration of selenium as a chemopreventive agent raises the question whether the antioxidant selenium, alone or in combination with other dietary antioxidants, could protect non-tumor cells from the clastogenic effect of cisplatin. Therefore, the present study was undertaken to investigate the modulatory effects of selenium, combined or not with vitamin C, on cisplatin-induced chromosomal aberrations in Wistar rat bone marrow cells. The animals were sacrificed 18, 24, or 72 h after cisplatin injection. The results obtained in Wistar rat bone marrow cells showed a slight nonsignificant reduction in the total number of chromosomal aberrations induced by cisplatin (5 mg/kg b.w.) observed in the animals that received a pretreatment with a single dose of selenium (2 mg/kg b.w.). The administration of two doses of selenium (1 mg/kg b.w.) also did not inhibit the chromosomal damage induced by cisplatin. In the present study, no protective response was obtained with either a single or double dose of selenium in rats treated with cisplatin. Furthermore, the combination between selenium+vitamin C was no more effective than vitamin C alone in the protection against damage caused by this antitumor drug. Further investigations, with other forms of selenium, are necessary to elucidate a possible protective role of selenium in clastogenicity induced by free radicals generated by antitumor drugs.     

Ameliorative effect of vitamin C on the haematological changes induced by exposure of chlorpyriphos and lead acetate in Wistar rats

The present study was designed to evaluate the effects of chlorpyriphos, lead acetate and vitamin C alone and in combinations, on various haematological parameters in Wistar rats. Rats of 150–200 g body weight were divided into eight groups of six animals each and were subjected to various daily oral treatment regimes for 98 days. Group C served as control receiving only corn oil, group CP received chlorpyriphos at 5.5 mg/kg in corn oil and group L received lead acetate at100?ppm in water, whereas animals in group CP + L received a combination of chlorpyriphos at 5.5 mg/kg in corn oil and lead acetate at 100 ppm in water. Group VC received vitamin C at 100 mg/kg in water; group CP + VC received a combination of chlorpyriphos at 5.5 mg/kg and vitamin C at 100 mg/kg; group L + VC received lead acetate at 100 ppm in water and vitamin C at 100 mg/kg and group CP + L + VC received chlorpyriphos at 5.5 mg/kg, lead acetate at 100 ppm in water and vitamin C at 100 mg/kg. Blood samples were collected on days 0, 30, 60 and 98 post exposure and analysed for packed cell volume (PCV), total erythrocyte count (TEC), haemoglobin (Hb), erythrocyte sedimentation rate (ESR), total leucocyte count (TLC) and differential leucocyte count. A significant decrease in TEC, PCV and Hb and a significant increase in ESR values were observed. However, lead acetate caused an increase in TLC while chlorpyriphos resulted in a decrease in TLC. Both of these toxicants potentiated toxicity of each other. The study demonstrated that treatment of chlorpyriphos- and lead-treated rats with vitamin C significantly altered some of the important haematological parameters revealing the protective effect of this vitamin against haematological alterations induced by chlorpyriphos and lead.     

Lipoxygenase metabolites mediate increased airways resonsiveness to histamine after acute platelet activating factor exposure in the guinea-pig

Platelet activating factor (Paf, 0.02 g/kg, i.v. bolus) caused an acute increase in airways responsiveness to histamine in anaesthetized guinea-pigs prepared for recording airways resistance (R _L ) and dynamic compliance (C _dyn ). Aspirin pretreatment (10 mg/kg, i.v.) attenuated the return of airways responsiveness to prechallenge levels. Pretreatment with the combined cyclooxygenase/lipoxygenase inhibitors BW 755C (20 mg/kg, i.v.) and ETYA (20 mg/kg, i.v.), or with the putative cysteinyl-containing leukotriene antagonist FPL 55712 (0.25 mg/kg/min, i.v.), or a Paf antagonist SRI 63441 (2.5 mg/kg, i.v.), prevented Paf-induced increased airways responsiveness. Inhibitors of leukotriene synthesis, BW 755C and ETYA, or action, FPL 55712, had variable effects of Paf-induced bronchoconstriction. These data suggest that lipoxygenase metabolites, possibly leukotrienes, may mediate an acute increase in airways responsiveness to histamine after Paf exposure.     

Hematological and bone marrow parameters in busulfan-treated rats: effects of silymarin extract

Busulfan is an alkylating agent that can be used in the treatment and control of chronic myeloblastic leukemia. Milk thistle seed extract of dried herb in 1 to 4 % silymarin is a powerful antioxidant flavonoid. In this study, busulfan and bone marrow suppression were used to assess whether the effect of silymarin can suppress cell death, or at least reduce it. Forty-two Wistar male rats were fed with a standard diet, divided into six groups of eight rats and treated as follows. Group 1—control group (received nothing). Group 2—control silymarin, 175 mg/kg/day silymarin was gavage for 14 days. Group 3—anemic control group, 20 mg/kg/day busulfan was injected intraperitoneally (i.p.) for 14 days. Group 4—experimental group 1 received 20 mg/kg/day busulfan (i.p.) for 14 days, and after 2 weeks, 175 mg/kg/day silymarin was gavage for 14 days. Group 5—two groups received 20 mg/kg/day dose busulfan (i.p.) for 14 days, and after 2 weeks, 250 mg/kg/day silymarin was gavage for 14 days. Group 6—three groups received 20 mg/kg/day dose busulfan (i.p.) for 14 days, and after 2 weeks, 325 mg/kg/day silymarin was gavage for 14 days. Hematological and bone marrow parameters were measured using standard routine procedures. The results showed that after 2 weeks, in the group that had received busulfan with healthy controls, leukocyte parameters were influenced more by the drug similar to the control group. In samples of bone marrow cells after treatment with silymarin, a slight difference between the groups was observed, but the cells are promyelocyte, myelocyte, and metamyelocyte, and band width in the control group of healthy controls and patient groups treated with silymarin was different. Decrease in bone marrow cells of control group was significantly different from the control group treated with silymarin. The effects of silymarin on bone marrow cells and peripheral blood leukocytes lead to reduced cell death, reducing oxidative stress and protecting cells against apoptosis, and the mechanisms, probably due to antioxidant properties, are unknown.     

Preliminary study on the protective effect of vitamin C on monosodium glutamate-induced hepatotoxicity in rats

Monosodium glutamate (MSG) is a food additive with a wide range of biological effects but its high dose and prolonged use can cause a toxic effect on the liver. Therefore, the present study was aimed at investigating the role of vitamin C in MSG-induced hepatotoxicity in rats. MSG was administered to rats (by gavage) at a dose of 6 mg/g body weight for 10 days to induce hepatotoxicity, and vitamin C at a dose of 500 mg/kg body weight was coadministered to evaluate its ameliorating effect by measuring alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in serum; superoxide dismutase (SOD) and catalase activities in liver fraction; lipid peroxidation; and liver weight. It was found that MSG significantly (P?<?0.05) induced lipid peroxidation (LPO), increased liver weight, and increased activity of SOD and catalase in the liver of animals. The activity of ALT and AST was also increased in the serum on MSG administration. Vitamin C (500 mg/kg) coadministered with MSG significantly reduced LPO and liver weight and decreased the hepatic activity of catalase, but the activity of SOD was not reduced significantly. Also, a significant reduction in ALT and AST activity was observed. MSG induced oxidative stress and hepatic toxicity in the experimental animals at a dose of 6 mg/g body weight. Vitamin C significantly reduced the oxidative stress and hepatic toxicity induced by MSG, thereby providing a protective effect against the MSG-induced hepatotoxicity. The protective effect is associated with decreased LPO and liver weight and decreased activities of catalase, ALT, and AST.     

Cisplatin nephrotoxicity: experimental and clinical studies

Cisplatin is currently one of the most used agents in the treatment of cancer and it is essential in the treatment of germ cell cancer. The use of the drug is hampered by side effects - especially renal toxicity which is dose limiting. The present work was undertaken to elucidate the pathophysiological mechanisms involved in cisplatin induced nephrotoxicity. Immediately after administration of cisplatin to dogs, renal blood flow (RBF) and glomerular filtration rate (GFR) remained unchanged, while proximal reabsorption rates decreased significantly. The cisplatin induced nephrotoxicity is thus initiated by an acute, mainly proximal tubular impairment, preceding alterations in renal hemodynamics. These data were confirmed in a micropuncture study in rats. At 48 to 72 hours after administration of cisplatin depressed renal function could be attributed to impairment of proximal as well as distal tubular reabsorptive capacities, now associated with increased renal vascular resistance. After administration of 4 cycles of 20 mg cisplatin/m2 d. for 5 days in humans, a small but significant decrease in 51Cr-EDTA clearance was observed. In the high-dose cisplatin group (40 mg/m2 d. for 5 days) a severe progressive decrease in GFR was observed during treatment and GFR remained decreased for up to 2 years after termination of treatment. The observation of an acute increase in N-acetyl-beta-D-glucosaminidase and beta-2-microglobulin indicates a primary tubular effect of cisplatin also in humans. A marked reduction of proximal tubular reabsorptive capacities of sodium and water was also observed in this group, together with a decrease in distal tubular function. These changes persist for at least 6 months after treatment. In the high-dose group proteinuria developed. This was mainly of tubular origin during cisplatin infusion and of glomerular origin between treatment cycles. Cisplatin remains one of the most potent antineoplastic agents ever developed. Further work should be performed to reduce its potential for renal toxicity.     

Cyclosporin reduces renal blood flow through vasoconstriction of arcuate arteries in the hydronephrotic rat model

Summary Besides its beneficial effects in organ transplantation cyclosporin (CyA) exhibits nephrotoxic (and other) side effects. CyA nephrotoxicity is associated with a decrease in glomerular filtration rate. Two mechanisms of action have emerged. First, tubular destruction with secondary reduction in renal blood flow and glomerular filtration rate; second, decrease in renal blood flow with secondary interstitial fibrosis. We studied the effect of an acute infusion of CyA in the hydronephrotic rat kidney model, which lacks tubular structures completely. Hence, only the direct vascular effects of CyA were determined. Five groups (G) of rats were studied by television microscopy. G I(n=7) received CyA (30 mg/kg, i.v.) dissolved in cremophore/plasma; G II (n=5), time control 1, received cremophore/plasma instead of CyA; G III (n=8), received CyA 30 mg/kg followed by 20 mg/kg CyA i.v. dissolved in an ethanol/tween solution; G IV (n=3), time control 2 received ethanol/ tween alone in the experimental period; in G V, CyA was applied locally onto the surface of the kidney with concentrations increasing from 10^–7 to 10^–5 M. CyA caused profound reduction in the diameter of arcuate arteries in groups I and III, in contrast to the time control groups II and IV. The vasoconstriction could be partially reversed by the calcium-channel blocker nitrendipine, and completely reversed with acetyl-choline. Glomerular blood flow decreased due to CyA and could not be completely normalized by either drug. Increasing the dosage from 30 to 50 mg/kg was not associated with further reduction in blood flow. Local application of CyA (G V) did not demonstrate vasoconstriction. These observations indicate that CyA causes vasoconstriction of large renal arteries through as yet unknown vascular mechanisms, without specific CyA-associated tubular damage being a prerequisite.List of abbreviations CyA Cyclosporin A - G Study group - n Number of Animals     

Acute and chronic administration of immunomodulators induces anorexia in Zucker rats

To investigate the possible involvement of leptin signaling in lipopolysaccharide (LPS) anorexia, we compared the anorectic effect of LPS in genetically obese (fa/fa) Zucker rats and in their lean (Fa/?) counterparts. The effects of interleukin-1beta (IL-1beta) and muramyl dipeptide (MDP) were also tested. LPS [100 microg/kg body weight (BW)], IL-1beta (2 microg/kg BW) and MDP (2.2 mg/kg BW) injected intraperitoneally (i.p.) at lights out reduced food intake similarly in obese and lean rats. LPS injection at 500 or 1000 microg/kg BW (i.p.) also reduced food intake and BW similarly in obese and lean rats, but obese regained BW faster than lean rats. LPS (2.45 microg or 9.8 microg/h/rat) administered chronically with i.p. implanted osmotic pumps reduced food intake similarly on experimental day 1, regardless of the genotype. After day 3, the lean rats' anorectic response and recovery were dose-dependent, whereas the anorectic response in obese rats was minimally affected by dose (significant dose effect only on day 3). Again, obese rats regained lost BW faster than lean rats. These results do not support a role for leptin as the sole mediator of anorexia induced by bacterial products (LPS and MDP) and IL-1beta.     

Comparative efficacy of chamomile against omeprazole in aspirin-induced gastric ulcer in rats

The aim of the study was to compare the efficacy of chamomile versus omeprazole in the treatment of aspirin-induced gastric ulcer in rats. Animals were randomly assigned into three groups A, B and C (n?=?10 each). Aspirin (200 mg/kg, intragastric (i.g.)) was administered for three consecutive days, and then, two animals from each group were euthanized and formed the aspirin-induced gastric ulcer control group. The remaining animals (n?=?8 in each group) were administered with the following treatments: normal saline 9 % (0/5 mL, i.g.) (group A), omeprazole (2.3 mg/kg, i.p.) (group B) or chamomile decoction (25 mL/kg, i.g.) (group C) daily for 2 weeks. Histological analysis of tissue harvested from rats in groups B and C showed no significant difference, since ulcers in both treatment groups were completely cured. The results of this study suggest that chamomile could be used for the treatment of nonsteroidal anti-inflammatory drug-induced ulcers as an inexpensive alternative to omeprazole.     

Increased airways responsiveness to histamine induced by platelet activating factor in the guinea-pig: possible role of lipoxygenase metabolites

In anaesthetized guinea-pigs pretreated with propranolol (1 mg/kg, i.v.), platelet activating factor (Paf, 0.02 g/kg, i.v.) caused an acute increase in airways response to histamine (0.5–3.0 g/kg, i.v.) measured as intratracheal pressure. Treatment with the cyclooxygenase inhibitors, aspirin (10 mg/kg, i.v.) or indomethacin (5 mg/kg, i.v.), enhanced the magnitude and duration of this effect but a combined lipoxygenase/cyclooxygenase inhibitor, BW 755C (20 mg/kg, i.v.), prevented the increase in responsiveness. In aspirin treated animals, a putative lipoxygenase inhibitor NDGA (10 mg/kg, i.v.). or atropine methyl nitrate (1 mg/kg, i.v.) or bilateral vagotomy reduced the magnitude of Paf-induced increased histamine responses but did not prevent the effect.Bronchoconstriction induced by Paf was variably influenced by the drug treatments. These data suggest that Paf causes an acute increase in airways responsiveness to histamine in the guinea-pig through a mechanism that may, in part, be dependant on the release of lipoxygenase metabolites.     

Influence of zinc supplementation on histopathological changes in the stomach,liver, kidney,brain, pancreas and spleen during subchronic exposure of Wistar rats to glyphosate

A subchronic toxicity study was carried out to determine the glyphosate-induced histopathological changes in the stomach, liver, kidney, brain, pancreas and spleen of rats and the attendant ameliorative effect when pretreated with zinc at the dose rate of 50 mg/kg body weight. The rats were exposed to two doses of the glyphosate (375 and 14.4 mg/kg body weight) for the period of 8 weeks which was the duration of the study, and some groups were exposed to the glyphosate after pretreatment with zinc. The histopathological changes recorded during the study were only in the rats exposed to the glyphosate at the dose rate of 375 mg/kg body weight except the vacuolation encountered in the brains and haemosiderosis in the spleens of rats exposed to zinc alone. Degenerated mucosal epithelial cells which involved the muscularis mucosa and the glands in the stomachs of rats were seen microscopically. Hepatic cells degeneration especially at the portal areas of the livers of rats was observed. The histopathological examination of the kidneys showed glomerular degeneration, mononuclear cells infiltration into the interstices of the tubules and tubular necrosis. The conspicuous changes seen in the brains were neuronal degeneration. Pancreatic acinar cells were degenerated while the spleen of the rats showed depopulated splenic cells in both the red and the white pulps. It was concluded that zinc supplementation in rats prior to glyphosate exposure ameliorated the histopathological changes observed in the stomach, liver, kidney, brain, pancreas and spleen with no observable alteration in the histoarchitecture in the organs of the zinc-supplemented rats.     

Cisplatin-induced nephrotoxicity causes altered renal hemodynamics in Wistar Kyoto and spontaneously hypertensive rats: Role of augmented renal alpha-adrenergic responsiveness

The pathogenesis of cisplatin-induced renal failure is related to reduced renal blood flow due to severe tubular damage and enhanced renovascular resistance. It is also known that alpha(1)-adrenoceptors, the major subtype of alpha-adrenoceptors in renal vasculature play the pivotal role in regulating renal hemodynamics. With this background, we have hypothesized that the altered renal hemodynamics and enhanced renovascular resistance in cisplatin-induced renal failure might be caused by the altered alpha-adrenergic responsiveness with a possible involvement of alpha(1)-adrenoceptors in the renal vasculature. In a unique experimental approach with anesthetized rats, this study has therefore examined if there is any shift in the renovascular responsiveness to renal nerve stimulation and a series of alpha-adrenergic agonists in Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats with cisplatin-induced renal failure in comparison with their body weight-matched normal controls. Thirty-two male rats of both WKY (n=16) and SHR (n=16) origin with body weight 236+/-7.9 g received cisplatin (5mg/kg i.p.). The renal failure was confirmed in terms of significantly reduced renal blood flow, reduced creatinine clearance, increased fractional excretion of sodium, increased kidney index (all P<0.05) and tubular damage. After 7 days of cisplatin, the overnight fasted rats were anesthetized (sodium pentobarbitone, 60 mg/kg i.p.) and renal vasoconstrictor experiments were done. The changes in the vasoconstrictor responses were determined in terms of reductions in renal blood flow caused by electrical renal nerve stimulation or intrarenal administration of noradrenaline, phenylephrine and methoxamine. It was observed that in the cisplatin-treated renal failure WKY and SHR rats there were significant (all P<0.05) reductions in the renal blood flow along with significantly (P<0.05) higher renal adrenergic responsiveness as compared with their non-renal failure controls. The data showed that in the renal failure WKY and SHR rats, the altered renal hemodynamics might be caused by an augmented renal adrenergic responsiveness. The results obtained further led us to suggest that the augmented renal adrenergic responsiveness in the cisplatin-induced renal failure rats were possibly mediated by the alpha(1)-adrenoceptors.     

Mechanism of kidney injury caused by bevacizumab in rats

Objective: We investigate kidney injury caused by high dose bevacizumab to uncover the possible mechanisms involving in this process. Methods: Forty rats were divided into four groups: cisplation group (treated with 1 mg/kg cisplation), Bev-high group (treated with 5 mg/kg bevacizumab); Bev-low group (treated with 2.5 mg/kg bevacizumab) and control group (treated with saline). The urine microalbumin, serum cystatin C, blood urea nitrogen and serum creatinine were detected in the four group rats, respectively. The immunoglobulin of IgG, IgA and IgM and protein of VEGF (vascular endothelial growth factor) and nephrin were detected by immunohistochemical methods. Results: All the levels of microalbumin, cystatin C, serum creatinine and blood urea nitrogen in Bev-high group were significantly higher than those in normal control group (P < 0.05). The cystatin C was much more increased in kidney Bev-high group than cisplatin and Bev-low groups (P < 0.05). The light microscope showed a normal glomerular morphology in the four groups, while the electronic microscopy showed the podocytes were extensively fused in cisplatin group and Bev-high group. The two groups were found IgG and IgM deposition as well. The VEGF in kidney amples were down regulated in high dose bevacizumab group, whereas the nephrin and IgA showed no significant expression changes at all. Conclusion: Bevacizumab increases the risk of injury in glomerular filtration barrier in a dose dependent model. The injury may not only associate with the rising level of proteinuria but also with podocyte-dependent membrane structures.     

The effect of bromhexine on experimentally induced diabetic nephropathy.

Diabetes was induced in male Wistar rats by a single i.v. injection of streptozotocin (40 mg/kg). Animals were treated with bromhexine at 2 dose levels (2.5 mg/kg/day and 25 mg/kg/day) for 13 months thereafter and compared to non-diabetic controls and untreated diabetic animals. Renal pathology showed a significant increase in glomerular volume and basement membrane thickening in untreated diabetic animals. The higher dose bromhexine treated diabetic animals showed a significant decrease in glomerular volume as compared with diabetic animals not given bromhexine.     

The effect of bromhexine on experimentally induced diabetic nephropathy

Diabetes was induced in male Wistar rats by a single i.v. injection of streptozotocin (40 mg/kg). Animals were treated with bromhexine at 2 dose levels (2.5 mg/kg/day and 25 mg/kg/day) for 13 months thereafter and compared to non-diabetic controls and untreated diabetic animals. Renal pathology showed a significant increase in glomerular volume and basement membrane thickening in untreated diabetic animals. The higher dose bromhexine treated diabetic animals showed a significant decrease in glomerular volume as compared with diabetic animals not given bromhexine.