Experimental Gentamicin Nephrotoxicity Research Articles

The Investigation Protective Effect of Tarantula Cubensis Extract in Rats Induced Experimental Gentamicin Nephrotoxicity

Gentamicin (GM), which is used in the treatment of infections caused by gram-negative bacteria, has limited clinical use due to its serious nephrotoxic side effects. Tarantula cubensis extract (TCE) is a homeopathic product that is widely used and proven to be effective in veterinary medicine to benefit from its regeneration, demarcation, antiphlogistic and resorptive effects. The aim of the study was to investigate the possible protective effects of TCE against these negative effects of Gentamicin, which is one of the drugs that trigger the formation of free radicals in the body, in terms of oxidative stress, apoptosis and antioxidant parameters. In this study, rats were divided into four equal groups. Groups; Control, GM, TCE, GM+TCE. Blood and kidney tissue samples were taken 24 hours after the last injection. Urea and creatinine analysis were performed in serum, MDA, SOD and TAS analysis were performed in kidney and serum samples. Bcl-2 and Bax analyzes and histopathological evaluations were performed in the kidney tissue. An increase in MDA, creatinine and urea levels, and a decrease in TAS and SOD levels were observed in the GM group compared to the control group. On the other hand, in the GM+TCE group, a decrease was observed in increasing parameters compared to the GM group, and an increase in TAS and SOD levels was observed. In the histopathological and immunohistochemical examination of kidney tissue, it was determined that pathological disorders and increased apoptosis (decrease in Bcl-2, increase in Bax) in the GM group decreased with TCE application. In conclusion, in the light of the data in this study, we believe that high-dose gentamicin causes side effects in the kidneys, while TCE may have antioxidant, antiapoptotic, protective and curative effects. However, additional studies are needed to confirm this assumption.

Kidney and urine enzyme activity in experimental gentamicin nephrotoxicity in the Sprague-Dawley rat.

Kidney and urine enzyme activity in experimental gentamicin nephrotoxicity in the Sprague-Dawley rat.

The relationship between enzymuria and kidney enzyme activities in experimental gentamicin nephrotoxicity.

The aim of this study was to investigate the relationship between the urine excretion and kidney activities of enzymes predominantly located in the proximal renal tubule, viz. the lysosomal hydrolase N-acetyl-beta-D-glucosaminidase (NAG) and the predominantly brush border enzymes alanine aminopeptidase (AAP) and gamma-glutamyltransferase (GGT) in an experimental model of gentamicin nephrotoxicity. Groups of six animals received either gentamicin (50 mg/ kg/day by intraperitoneal injection) or saline daily and were killed after 4, 7, 10, or 14 days of treatment. Gentamicin nephrotoxicity was characterized by reduced creatinine clearance rates and increased urinary flow rate and glycosuria, but only on day 14. Structural changes included a similar degree of vacuolation of the renal proximal convoluted tubules (PCT) in all animals sacrificed on days 11 and 14, some evidence of PCT brush border loss, and the presence of protein casts on day 14. Following gentamicin treatment, increased NAG, AAP, and GGT enzymuria were noted at all time points tested. However, while the increases in urine AAP and GGT activity were paralleled by decreased total renal activity, total kidney NAG activity increased on days 4, 7, and 11 before falling back to pretreatment values on day 14. Interestingly, NAG enzymuria was highest in those animals with protein casts in the lumen of the PCT. The results suggest that increased AAP and GGT enzymuria reflect loss of brush border integrity while increased NAG enzymuria is consistent with the autophagic response of the kidney to acute injury.

Ultrasonographic Evaluation of Kidney Damage in Dog with Gentamicin Nephrotoxicity

Acute tubular necrosis was induced by experimental gentamicin nephrotoxicity to follow and describe the changes in ultrasonographic appearance of the kidney. Sonograms were evaluated for information on size, shape and renal structure, specifically including focal, multifocal, or diffuse alterations in renal cortical, medullar, sinusal and perinephric echogenity and intensity (compared to that of the splenic and hepatic paranchmys). Following 12 hours of no feeding, clinical, biochemical and ultrasonographic examinations were conducted and then gentamicin sulphate (10 mg/kg body weight, t.i.d.) was injected for 10 consecutive days. The clinical states of the dogs were observed, and urine dip stick examinations, microscopic examination of urine sediment, biochemical [blood: BUN, serum creatinine (CR), albumin PO4-,Na+,K+ concentrations; urine: total protein (TP) and creatinine concentrations, N-acetyl-b-D-glucosaminidase (NAG), g-glutamly transferase (GGT), alkaline phosphates (ALP) activities and their creatinine rations, fractional clearences of Ca2+, PO4-, Na+,K+] analysis and ultrasonographic examinations of the kidneys were performed every other day for 15 days. Heamaturia, proteinuria, glucosuria and granular casts in the microscopic examination of urine sediment were first determined on the 8th day of the experiment. BUN, serum CR and PO4- and K+ concentrations were significantly increased on the 3rd, 9th, and 13th days of the experiment, respectively (p

Attenuation by daptomycin of gentamicin-induced experimental nephrotoxicity.

Previously, daptomycin was shown to reduce tobramycin nephrotoxicity in vivo (D. Beauchamp, M. Pellerin, P. Gourde, M. Pettigrew, and M. G. Bergeron, Antimicrob. Agents Chemother. 34:139-147, 1990; C. A. Wood, H. C. Finkbeiner, S. J. Kohlhepp, P. W. Kohnen, and D. C. Gilbert, Antimicrob. Agents Chemother. 33:1280-1285, 1989). Female Sprague-Dawley rats were treated with saline (NaCl, 0.9%), daptomycin (10 mg/kg of body weight every 12 h, subcutaneously), gentamicin (30 mg/kg/12 h, intraperitoneally) or with a combination of daptomycin plus gentamicin over a 10-day period. Animals were killed 4, 10, and 20 days after the end of treatment. Four days after the end of drug administration, gentamicin and daptomycin levels in the renal cortices of animals treated with the combination of daptomycin and gentamicin were significantly higher than in those of rats given gentamicin or daptomycin alone (P < 0.01). Despite the higher cortical concentrations of gentamicin, rats given the combination of gentamicin and daptomycin had less reduction in renal cortex sphingomyelinase activity, less evidence of regeneration of cellular cortical cells ([3H]thymidine incorporation into cortex DNA), lower creatinine concentration in serum, and less histopathologic evidence of injury than rats given gentamicin alone. By immunogold technique, both daptomycin and gentamicin were localized to the lysosomes of proximal tubular cells, regardless of whether animals received the drugs alone or in combination. Interestingly, myeloid body formation occurred in both those animals given gentamicin alone and those given daptomycin plus gentamicin. No significant changes were observed for all groups between 10 and 20 days after the end of therapy, suggesting that the toxicity of gentamicin was not delayed by the concomitant injection of daptomycin. The results confirm that daptomycin can attenuate experimental gentamicin nephrotoxicity.

Pharmacologic limits of the protective effect of polyaspartic acid on experimental gentamicin nephrotoxicity

Polyaspartic acid (PAA) ameliorates experimental gentamicin nephrotoxicity despite marked accumulation of gentamicin in the renal cortex. The experiments described here probe the extent of PAA's nephroprotective action when increasing doses of gentamicin, in excess of an established nephrotoxic dose (40 mg/kg of body weight per day), are administered. After 10 days, virtually complete nephroprotection was conferred by PAA coadministered to animals receiving three times the nephrotoxic dose (120 mg/kg/day) of gentamicin.

Duration of the protective effect of polyaspartic acid on experimental gentamicin nephrotoxicity.

It is known that daily polyaspartic acid (PAA) protects the kidney from gentamicin nephrotoxicity in a standardized rat model despite marked cortical accumulation of the aminoglycoside. The present experiments address the duration of PAA protection. When administered every other day, PAA provided functional and histologic protection against gentamicin-induced toxicity. A stepwise reduction in nephroprotection occurred as the dosage interval was prolonged.

Long-term protection of polyaspartic acid in experimental gentamicin nephrotoxicity

Polyaspartic Acid (PAA) protects the kidney from experimental gentamicin nephrotoxicity despite large increases in renal cortical gentamicin content. In these experiments, prominent cytoplasmic vacuoles were noted in all animals that received PAA with or without gentamicin. The present study showed that there were no renal structural or functional consequences of PAA given alone or with gentamicin for up to 14 days, followed by a 16-week washout period. Creatinine clearance was similar to that of controls in animals that received gentamicin and in those that received PAA alone. Thus, complete functional protection was conferred by PAA and gentamicin, confirming previous reports from our laboratory. There was no protection by PAA from the nephrotoxic effects of mercuric chloride and cis-platinum.

Polyaspartic Acid Prevents Experimental Aminoglycoside Nephrotoxicity

The influence of the polyamino acid polyaspartic acid (PAA) on experimental aminoglycoside nephrotoxicity was determined. PAA prevented all measured functional and pathologic evidence of gentamicin nephrotoxicity for less than or equal to 27 d of study. All the animals given PAA, either alone or with gentamicin, developed prominent cytoplasmic vacuoles in the cells of the renal proximal convoluted tubules; the vacuoles in rats given just PAA differed from those observed in rats given PAA plus gentamicin. Rats given PAA plus gentamicin accumulated roughly 10 times more renal aminoglycoside as did rats given gentamicin alone. Immunohistochemical localization studies confirmed the presence of increased amounts of gentamicin in the cytoplasm of the tubular cells of animals given gentamicin plus PAA. PAA did not alter the in vitro antimicrobial activity of gentamicin versus Escherichia coli or Pseudomonas aeruginosa. These studies demonstrate the ability of PAA to prevent experimental gentamicin nephrotoxicity.

Microsomal protein synthesis inhibition: an early manifestation of gentamicin nephrotoxicity

Aminoglycoside antibiotics achieve bacterial killing by binding to bacterial ribosomes and inhibiting protein synthesis. To examine whether similar mechanisms could be present in renal tubular cells prior to the onset of overt proximal tubular necrosis due to these drugs, we isolated microsomes from Fischer rats given 20 mg/kg gentamicin every 12 h subcutaneously for 2 days and from vehicle-injected controls. Concomitant studies of renal structure, function, and mitochondrial respiration were carried out. [3H]leucine incorporation into renal microsomes of treated animals was reduced by 21.9% (P less than 0.01), whereas brain and liver microsomes from the same animals were unaffected. Gentamicin concentration in the renal microsomal preparation was 56 micrograms/ml, a value 7- to 10-fold above concentrations necessary to inhibit bacterial growth. Conventional renal function studies were normal (blood urea, serum creatinine, creatinine clearance). Treated animals showed only a mild reduction of inulin clearance, 0.71 compared with 0.93 ml.min-1.100 g-1 in controls (P less than 0.05), and an increase in urinary excretion of N-acetylglucosaminidase of 20 compared with 14.8 units/l (P less than 0.05). Renal slice transport of p-aminohippuric acid, tetraethylammonium, and the fractional excretion of sodium were well preserved. There was no evidence, as seen by light microscopy, of proximal tubular necrosis. Mitochondrial cytochrome concentrations were normal and respiratory activities only slightly reduced. Processes similar to those responsible for bacterial killing could be involved in experimental gentamicin nephrotoxicity before overt cellular necrosis.

A focus of tissue necrosis increases renal susceptibility to gentamicin administration

The purpose of this study was to determine whether a retained focus of necrotic tissue predisposes to aminoglycoside-induced acute renal failure (ARF). Rats were subjected to either (1) 25% liver ligation, creating a focus of ischemic tissue which was left in place; (2) 25% liver resection; or (3) sham liver ligation. Gentamicin, 80 mg/kg bid, was administered for two days after surgery to all three groups. A fourth group was subjected to 25% liver ligation but no gentamicin therapy. Only rats subjected to partial liver ligation plus gentamicin treatment developed ARF, manifested by azotemia (BUN 80 +/- 2; creatinine 1.63 +/- 0.21; mg/dl) and tubular necrosis. This occurred in the absence of any discernible reduction in arterial blood pressure, renal blood flow, excessive weight loss, or ascites formation. The partial liver ligation-gentamicin group had 70% higher renal gentamicin concentrations than the liver resection-gentamicin controls (P = 0.01). To assess whether factors released from necrotic liver might account for these findings, additional rats were infused with: (1) 1 ml of a soluble liver extract alone; (2) 1 ml of liver extract plus gentamicin; or (3) 1 ml of saline plus gentamicin. Only the liver extract/gentamicin group developed ARF (BUN 88 +/- 13; creatinine 1.46 +/- 0.25). This occurred in association with a 110% increase in renal gentamicin uptake (P less than 0.03). In separate experiments, 5 ml liver extract infusions caused ARF (BUN 118 +/- 7; creatinine 2.1 +/- 0.18) without gentamicin treatment. In conclusion, a focus of liver necrosis can predispose to experimental gentamicin nephrotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Modification of experimental gentamicin nephrotoxicity by selective parathyroidectomy.

Dietary calcium loading reduces gentamicin nephrotoxicity in rats. Since parathyroid hormone increases renal brush border membrane anionic phospholipids, the putative gentamicin receptors, the effects of selective parathyroidectomy on gentamicin nephrotoxicity were examined. Male Fisher 344 rats underwent parathyroidectomy or sham surgery. All animals were fed a diet containing 0.5% calcium for 2 wk prior to gentamicin, 20 mg/kg twice daily for 6 and 10 days. Other parathyroidectomized rats were fed a 4% calcium diet for 2 wk and treated similarly with gentamicin On day 6, serum creatinine (mg/100 ml) was 2.0 +/- 0.9 in the sham-operated animals, 1.7 +/- 1.6 in the parathyroidectomized animals on the 0.5% diet, and 0.8 +/- 0.1 in the parathyroidectomized animals on the 4% diet. By 10 days, the sham-operated animals had creatinine values of 6.3 +/- 1.6 (mg/100 ml) compared with 1.7 +/- .9 in the parathyroidectomized animals on the same diet and 0.8 +/- 0.2 in the 4% diet animals. More severe tubular necrosis was present in the sham-operated compared with the parathyroidectomized animals. High calcium diet in the parathyroidectomized animals produced structural and functional protection from gentamicin nephrotoxicity. Human parathyroid hormone (1-34) 20 IU twice daily given subcutaneously to a separate group of parathyroidectomized rats, eliminated the protective effect of parathyroidectomy on renal structure and function. Parathyroidectomy modifies experimental gentamicin nephrotoxicity. The additional protective effect of dietary calcium loading may be independent of parathyroid ablation.

Effect of amiloride on experimental gentamicin nephrotoxicity.

Potassium and magnesium deficiency have been reported as risk factors for experimental gentamicin nephrotoxicity. Amiloride, a potassium-sparing diuretic, also leads to increased renal magnesium reabsorption. Amiloride, 2 mg/kg/day, was given to groups of 8-12 Fischer 344 rats receiving gentamicin, 20 mg/kg b.i.d., for 3, 7, 10 and 14 days. Control animals received the vehicle for gentamicin, amiloride alone or gentamicin alone. The degree of renal failure and weight loss were similar in gentamicin and gentamicin + amiloride groups at all time points despite increases in serum potassium and magnesium in the amiloride-treated animals. Tubular dysfunction as assessed by depression of renal cortical slice uptake of p-aminohippurate and N-methylnicotinamide was not improved by the addition of amiloride. In addition, a comparable degree of tubular necrosis and regeneration was observed in all gentamicin-treated groups. Maximum gentamicin concentrations in the renal cortex did not differ. Thus, despite reduction of urinary losses of potassium and magnesium with resultant increased serum values, amiloride did not protect against experimental gentamicin nephrotoxicity. The tubular electrolyte wasting noted clinically is likely to be a result, rather than a cause of proximal tubular cell damage.

Morphological and functional aspects of experimental gentamicin nephrotoxicity in young beagles and foals.

A toxic nephropathy induced by gentamicin was investigated in young beagles and foals. Preliminary results indicated that a single 15 mg/kg dose of gentamicin administered to beagles produced subclinical functional and morphological changes in the kidney. Light histological lesions of aminoglycoside nephrotoxicosis were detected in all foals given gentamicin, suggesting an enhanced susceptibility of young horses to clinical renal dysfunction.

Reduction of experimental gentamicin nephrotoxicity in rats by dietary calcium loading.

Since gentamicin accumulates in the renal cortex before renal failure and calcium reduces gentamicin binding to cell membranes, we examined the effect of dietary calcium loading on gentamicin toxicity in male F344 rats. Rats were fed either a normal (0.5%)- or a high (4%)-calcium-content chow. Calcium loading did not alter inulin clearance, urinary excretion of sodium or total osmoles, or serum ionized calcium. However, calcium loading caused elevation of urinary calcium excretion and lowered urinary cyclic AMP levels. The data suggest that calcium loading may have slowed the accumulation of gentamicin (40 mg/kg per day) by the renal cortex. Histological and functional evidence of nephrotoxicity was delayed in onset and attenuated in magnitude. The results indicate that dietary calcium loading reduces experimental gentamicin nephrotoxicity. Protection may be associated with slower renal cortical accumulation of gentamicin. Calcium-dependent membrane or intracellular events may mediate this effect.

Failure of lysine to prevent experimental gentamicin nephrotoxicity.

Failure of lysine to prevent experimental gentamicin nephrotoxicity.

The influence of dosage regimen on experimental gentamicin nephrotoxicity: dissociation of peak serum levels from renal failure.

Peak serum levels of gentamicin were varied in rats by administering a standard nephrotoxic dosage of 40 mg/kg per day in one (QD), two, or three (TID) daily doses. The QD animals had the highest peak serum levels but showed no appreciable increase of serum creatinine concentrations over a 10-day treatment period. The TID rats had the lowest peak serum levels, but, after 10 days of drug administration, the serum creatinine concentration (2.8 +/- 0.2 mg/100 ml, mean +/- SE) was significantly higher than in control rats (0.6 +/- 0.01 mg/100 ml) (P less than 0.001). After two days of gentamicin treatment, the renal concentration of gentamicin was 269 +/- 77 micrograms/g in the QD rats and 820 +/- 29 micrograms/g in the TID rats (P less than 0.001). In this rat model, the frequency of doses was a more important factor in the development of nephrotoxicity than the peak serum concentration of gentamicin. The results suggest that dose frequency should be considered when data from different laboratories are compared.

Furosemide enhancement of experimental gentamicin nephrotoxicity: comparison of functional and morphological changes with activities of urinary enzymes.

Dogs were given gentamicin (10 mg/kg) intramuscularly every 8 hr for 10 days. Levels of serum creatinine rose by day 6 (0.91 +/- 0.08 vs. 0.75 +/- 0.02 mg/dl for controls, P less than 0.05) and of blood urea nitrogen by day 8 (24.3 +/- 4.80 vs. 16.1 +/- 0.90 mg/dl for controls, P less than 0.05). Gentamicin nephrotoxicity occurred earlier and was more marked when furosemide (2 mg/kg) was added: the level of serum creatinine by day 6 was 1.62 +/- 0.25 mg/dl (P less than 0.05), and the level of blood urea nitrogen by day 8 was 181 +/- 23.5 mg/dl (P less than 0.01). Elevations in the activities of the urinary enzymes beta-glucuronidase, N-acetyl-beta-glucosaminidase, and muramidase preceded rises in levels of serum creatinine and blood urea nitrogen. Examination of serial percutaneous renal biopsy specimens showed that gentamicin administration was associated with hyaline droplet degeneration, lysosomal changes, and, later, cell necrosis (primarily of the proximal tubules). Changes in renal morphology were more severe and occurred earlier when furosemide was administered concomitantly. In summary, furosemide enhanced gentamicin nephrotoxicity. Enzymuria was an early sign of gentamicin nephrotoxicity.