黄芪和白术对庆大霉素肾毒性的保护作用

目的为减轻庆大霉素的肾毒性,应用中药黄芪、白术进行了防治肾毒性的研究。方法给大鼠腹腔注射庆大霉素制成中毒模型,分别注射黄芪、白术预防肾毒性,用药前、后检测大鼠的肾功能、尿酶等指标,实验结束后进行肾光镜、电镜检查。结果各实验组尿(N-乙酰-β-D氨基葡萄糖苷酶)NAG酶均比正常组增高,其中模型组明显增高。模型组肾皮质中丙二醛(MDA)含量比其它各组增高,而预防组与正常组之间差异不显著。肾皮质谷胱甘肽过氧化物酶(GSH-Px)活性较正常对照组下降,且模型组较各预防组下降明显。光镜检查发现模型组肾近曲小管上皮细胞广泛变性与坏死,各预防组有灶状至片状变性,偶见坏死。结论黄芪、白术对庆大霉素的肾毒性有保护作用。     

Silymarin prevents adriamycin-induced cardiotoxicity and nephrotoxicity in rats

Adriamycin is a potent anticancer agent, its clinical use is limited for its marked cardiotoxicity and nephrotoxicity. The present study aimed to investigate the possible protective role of the natural antioxidant silymarin on ADR-induced heart and kidney toxicity. Studies were performed on four groups of rats. 1--control group, 2--silymarin group (50 mg/kg), 3--adriamycin group (10 mg/kg), 4--adriamycin+silymarin group. On the third day after ADR injection, plasma was separated for determination of LDH, CPK, cholesterol and total lipids. 30 days after ADR injection, plasma was separated for determination of creatinine and urea levels. Frozen heart specimens (72 h) and frozen kidney specimens (30days) were used for estimation of lipid peroxides and GSH contents. Histopathological examinations of heart and kidney sections were also done. Pretreatment of ADR-treated rats with silymarin resulted in a significant decrease in the plasma CPK, LDH, creatinine and urea. On the other hand silymarin pretreatment did not change ADR-induced hyperlipidemia. Silymarin pretreatment significantly decreased the myocardial MDA contents. In addition, silymarin pretreatment normalized renal tissue contents of MDA and GSH. Histopathological examination of heart and kidney sections revealed that ADR caused only mild myocardial injury in silymarin pretreated rats. Also, silymarin pretreatment inhibited ADR-induced renal tubular damage in rats. These results have suggested that, silymarin ameliorated ADR-induced cardiotoxicity and protected against ADR-induced nephrotoxicity in male albino rats. The mechanisms of silymarin induced protection against ADR-induced toxicities were proved to be due to inhibition of lipid peroxidation and protection against GSH depletion.     

Mechanisms of bee venom-induced acute renal failure.

The spread of Africanized bees in the American continent has increased the number of severe envenomation after swarm attacks. Acute renal failure (ARF) is one of the major hazards in surviving patients. To assess the mechanisms of bee venom-induced ARF, rats were evaluated before, up to 70 min and 24h after 0.5mg/kg of venom injection. Control rats received saline. Bee venom caused an early and significant reduction in glomerular filtration rate (GFR, inulin clearance, 0.84+/-0.05 to 0.40+/-0.08 ml/min/100g, p<0.0001) and renal blood flow (RBF, laser Doppler flowmetry), which was more severe in the cortical (-72%) than in the medullary area (-48%), without systemic blood pressure decrease. Creatine phosphokinase, lactic dehydrogenase (LDH) and serum glutamic oxaloacetic transaminase increased significantly, pointing to rhabdomyolysis, whereas serum glutamic pyruvic transaminase and hematocrit remained stable. Twenty-four hours after venom, RBF recovered but GFR remained significantly impaired. Renal histology showed acute tubular injury and a massive tubular deposition of myoglobin. Venom was added to isolated rat proximal tubules (PT) suspension subjected to normoxia and hypoxia/reoxygenation (H/R) for direct nephrotoxicity evaluation. After 60 min of incubation, 0.1, 2 and 10 microg of venom induced significant increases in LDH release: 47%, 64% and 86%, respectively, vs. 21% in control PT while 2 microg of venom enhanced H/R injury (85% vs. 55%, p<0.01). These results indicate that vasoconstriction, direct nephrotoxicity and rhabdomyolysis are important mechanisms in the installation of bee venom-induced ARF that may occur even without hemolysis or hypotension.     

Effect of cyclosporin A on glomerular filtration rate in children with minimal change nephrotic syndrome

Cyclosporin A (CyA) is now commonly used in the management of children with steroid-dependent nephrotic syndrome. In order to assess nephrotoxicity related to CyA therapy, we measured glomerular filtration rate (GFR) on 123 occasions in 24 children with minimal change nephrotic syndrome receiving CyA. GFR was estimated from the plasma clearance of⁵¹chromium-EDTA every 3 months during CyA therapy of up to 27 months duration. There was a significant reduction in GFR after 3 months of CyA therapy [118±33 (SD) to 93±24 ml/min per 1.73 m²] but no further fall thereafter, although the reduction in GFR was sustained for the duration of CyA therapy. This reduction in GFR appeared to be reversible upon cessation of CyA, but careful monitoring of renal function is necessary in such patients to prevent the development of longer term nephrotoxic sequelae.     

Prevention of lithium nephrotoxicity in a novel one-hour model in rats

It is well established that lithium can cause morphologically visible damage to the kidneys of humans and animals. Although the clinical significance of its nephrotoxicity is debatable, it would be desirable to find a method to prevent lithium’s effect on the kidneys. Toward this end, we have developed a novel method for producing nephrotoxicity that will be useful for research on prevention. A single, large, toxic dose of lithium chloride (LiCl) caused necrosis of the distal convoluted tubules, which was visible by light microscopy in 30 min, had fully developed in 1 h, and had disappeared by the next day. The lesions were seen after IP or IV injections of fasted rats of three different strains. Equivalent doses of NaCl, KCl, MgCl₂ and combinations thereof had no such effect, nor did they inhibit nephrotoxicity when incorporated into the LiCl solution. However, relatively small doses of LiCl injected by any route 3 or 24 h beforehand prevented the nephrotoxicity. The mechanism of prevention is not known, but it does not involve reduction of lithium levels in the kidneys. Received: 30 July 1997/Final version: 18 November 1997     

Effect of sex hormone status on chloroform nephrotoxicity and renal mixed function oxidases in mice

In mice, only makes are susceptible to chloroform (CHCl₃) nephrotoxicity and the susceptibility appears to be related to renal mixed function oxidase activity. There were sex-related differences of renal cytochrome P-450 and b₅ concentrations and of ethoxycoumarin O-deethylase activity in mouse kidneys; in all cases activity was higher in males. Castration of male mice eliminated susceptibility to ChCl₃ nephrotoxicity and reduced renal mixed function oxidases to concentrations observed in female mice. Treatment of male and female mice with testosterone increased the susceptibility to ChCl₃ nephrotoxicity and increased renal mixed function oxidases to similar activities in both sexes. Previous data have suggested that CHCl₃ is metabolized in situ by the kidney, possibly by a mechanism similar to that occurring in the liver. The data from this investigation are consistent with the concept that CHCl₃ is metabolized by a cytochrome P-450-dependent mechanism in the kidney.     

Effects of various cephalosporins on the proximal tubule of the human kidney

Summary Cephamandol 6.0 g, cephazolin 6.0 g or cephacetrile or cephalothin 8.0 g were administered as short-term infusions on 3 consecutive days to informed volunteers, who had no history or evidence of impairment of renal funktion. There were 15 subjects in the cephamandol, cephacetrile and cephalothin groups and 14 subjects in the cephazolin group. Alanine-aminopeptidase, a characteristic tubule enzyme, was determined in a 24-hour urine 2 days before administration, during the 3 day administration and on the 4 subsequent days. In addition, alanine-aminopeptidase was also estimated immunologically in concentrated urine with the aid of an anti-brush border antibody. Cephamandol, cephazolin and cephalothin were completely without effect on the proximal tubule. Cephacetrile, on the other hand, showed clear reactions in 9 out of 15 subjects, in the form of elevated AAP activity in urine and in 6 of the cases membrane elimination was demonstrable immunologically. After withdrawal of the medication, the values of the responder group returned spontaneously to normal, i. e. no cumulative effect was detected. These investigations show that elimination of alanine-aminopeptidase in the urine is a very sensitive index of the action of cephalosporins on renal tubules.     

Acute renal failure after treatment with non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are known to have adverse effects on kidney function. Situations with a stimulated renin-angiotensin system such as volume depletion or pre-existing chronic renal failure predispose to acute renal failure (ARF) via inhibition of prostaglandin synthesis by NSAIDs. To date, NSAIDs are frequently used as antipyretic drugs even in situations predisposing to ARF. Within 20 months, seven children presenting with diarrhoea and/or vomiting and fever were treated with therapeutic doses (11.5–32 mg/kg per day) of ibuprofen for 1 to 3 days before developing ARF. Maximum plasma creatinine levels were 180–650 µmol/l. One patient required emergency dialysis for hyperkalaemia, uraemia, and hyperphosphataemia. After cessation of NSAID treatment and rehydration, all patients recovered completely with a normalised creatinine level after 3 to 9 days. Once the acute phase is controlled, long-term outcome is excellent. Interstitial nephritis, another possible adverse effect of NSAIDs, might require steroid treatment and is the major differential diagnosis. Only histological examination can confirm the exact pathomechanism of ARF after NSAID exposure. If immunological events are responsible for the ARF, the recovery period is usually longer. Conclusion: non-steroidal anti-inflammatory drugs are potentially dangerous in situations with even moderate volume depletion.Abbreviations AIN acute interstitial nephritis - ARF acute renal failure - COX cyclo-oxigenase - NSAIDs non-steroidal anti-inflammatory drugs - PG prostaglandin - RAS renin-angiotensin system     

Quantitative gene expression analysis in a nonhuman primate model of antibiotic-induced nephrotoxicity

Gene expression patterns using microarrays have been described for rodent models of nephrotoxicity. To determine if significant gene expression changes previously identified have application across multiple species, we studied quantitative gene expression changes in the kidneys of female cynomolgus monkeys after exposure to two nephrotoxicants. Animals were dosed with the aminoglycoside gentamicin (10 mg/kg), the experimental oligosaccharide antibiotic everninomicin (30 or 60 mg/kg), or a combination of gentamicin (10 mg/kg) and everninomicin (30 mg/kg) for 7 days. Monkeys receiving these drugs in combination developed renal lesions as early as Day 1. By Day 7, monkeys dosed with 60 mg/kg everninomicin alone also developed renal lesions, while the group exposed to both compounds had more extensive renal damage. The modulation of several genes previously reported to be associated with nephrotoxicity in rodent models was confirmed using quantitative real-time PCR. Among these, waf-1, matrix metalloproteinase-9, and vimentin exhibited changes consistent with the definition of a genomic indicator of toxicity. In addition, we identified three early gene biomarkers that may be predictive of drug-induced nephrotoxicity: clusterin, osteopontin, and hepatitis A virus cellular receptor-1. Logistic regression demonstrated a high degree of correlation between changes in gene expression and the probability of the development of histopathologic lesions. These results are the first confirming rodent gene expression changes associated with nephrotoxicity in a nonhuman primate model and provide preliminary evidence for identifying early gene expression changes predicting the onset of drug-induced renal tubular damage in cynomolgus monkeys.     

Effects of Vitamin E pretreatment on subacute toxicity of mixture of Co, Pb, and Hg nitrate-induced nephrotoxicity in rats

The aim of the study was to prove that Vitamin E has some beneficial effects on the kidneys of rats by protecting them from the toxicity of certain heavy metals. The protective effect of Vitamin E on Co, Pb, or Hg nitrate and a mixture of them induced nephrotoxicity was tested in a 3-months-old Norway strain (inberd) rat (Raltus norvigus) weighing 100–120 g. A study was carried out, which comprised one control group and five experimental groups. In this experiment, nitrate salts of Co, Pb, or Hg were administered subcutaneously (s.c.) either alone (0.5 mg/100 g body weight) for 4 weeks or as a mixture (0.25 mg/100 g body weight); Vitamin E internal control (250 IU/100 g body weight) was administered by oral gavage for 4 weeks, Vitamin E pretreatment for 7 days was followed by concomitant administration of Co, Pb, and Hg, respectively and Vitamin E pretreatment for 7 days, followed by concomitant administration of mixture of three heavy metals for 4 weeks. Blood and kidney tissue samples were taken from the control and all the experimental groups for biochemical and histological study. Nephrotoxicity was characterized by histopathological as well as renal function data. The main pathological changes in the kidney after Co administration were shrunken and degeneration of renal tubule cells, disturbance in their position, size, shape, and staining affinity. Treatment with Hg caused desquamation, necrosis, atrophy, and loss of renal tubule cells and glomeruli. Lead intoxication had a profound effect on the structure and consequently on the function of the rat kidney. Most renal tubule cells were very dense, dehydrated with obscure cytoplasmic details. Most nuclei were shrunken and pyknotic. Also, most glomeruli revealed shrinkage and widening of capsular space. On the other hand, subacute exposure with the mixture of the three heavy metals showed marked destruction and distortion of the renal tubule cells. Marked fibrosis between the damaged tubules was also seen. On the other hand in the recovery groups, i.e., in groups II and III, the previously observed histopathological changes were still present with regression of their intensity. Four-week oral administration with Vitamin E (250 IU/100 g body weight) revealed no abnormal histological findings as compared with the normal kidney of the control animal, except for some Malpighian corpuscles which demonstrated wide capsular space, and spherical masses were seen within the glomeruli. After pretreatment with Vitamin E for 7 days, followed by treatment with (0.5 mg/100 g body weight ) Co, Pb, or Hg nitrate alone or with their mixture (0.25 mg/100 g body weight) for 4 weeks, an improvement in the histological changes were observed compared to those previously seen in groups II and III. The glomeruli showed minimal degenerated changes, the tubular arrangement and cytoplasmic basophilia more or less similar to the normal control. It was also found that the heavy metals were investigated both alone and in combination; the serum creatinine and blood urea level were significantly increased, and this elevation was diminished by Vitamin E pretreatment.

According to the present results, it is concluded that combined exposure to a mixture of Vitamin E and examined heavy metals can minimize the histological alteration and diminish the serum creatinine and blood urea level. Also, it was found that the rank order of metal cytotoxicities was Hg > Co > Pb.