Nephrosis In Rats Research Articles

Effects of Human Alpha-1-Acid Glycoprotein on Aminonucleoside- Induced Minimal Change Nephrosis in Rats

A minimal change nephrosis was induced in rats by a single intraperitoneal injection of puromycin aminonucleoside (100 mg/kg). This resulted in increased urine protein output, plasma creatinine, blood urine nitrogen, and relative kidney weight. Electronoptically, there was a retraction of the glomerular podocytic foot processes. When human α₁-acid glycoprotein was injected at 600 mg/kg intravenously on experimental days 6, 7, 8, and 9 into these animals, urine protein output decreased significantly, and the number of podocytic foot processes increased significantly. α₁-Acid glycoprotein is rich in sialic acid and largely negatively charged. Its therapeutic role in nephrosis, which is characterized by a loss of sialic acid and a loss of negative charge, thereby leading to a loss of permselectivity, is discussed.

Dipyridamole and dilazep suppress oxygen radicals in puromycin aminonucleoside nephrosis rats.

Reactive oxygen species (ROS) are involved in the pathophysiology of puromycin aminonucleoside (PAN) nephrosis. To elucidate further the role of radicals in PAN nephrosis and the to determine the particular radical species scavenged by dipyridamole (DPM) and dilazep (DZ), we applied chemiluminescence and electron spin resonance (ESR) techniques. Chemiluminescence of glomeruli, which were isolated on day 7 from rats injected with 100 mg kg-1 PAN, was measured with or without scavengers. The inhibitory effects of DPM and DZ on hydroxyl radical adduct formation in the Fenton's reaction were evaluated using ESR. Chemiluminescence was greater in glomeruli from rats with PAN nephrosis than in the the glomeruli of control rats. This increase was suppressed by superoxide dismutase, catalase, dimethylthiourea and also by DPM and DZ. ESR indicated that DPM and DZ inhibited hydroxyl radical adduct formation with a second-order rate constant of 2.9 x 10(10) and 1.6 x 10(10) (mol L(-1) s(-1) respectively, similar to that of dimethylthiourea. DPM and DZ scavenge hydroxyl radicals, thereby alleviating PAN nephrosis.

The incidence of chronic progressive nephrosis in young Sprague-Dawley rats from two different breeders.

Chronic progressive nephrosis (CPN) in rats may not only become a problem in long-term toxicity studies but also in short-term studies, if the breeding stock is not carefully selected with respect to the kidney function. This paper presents differences in kidney function between young rats of the same strain, Sprague-Dawley, but from two different breeders ('set A' and 'set B' rats). In set A rats, protein in the urine was present in the males, which is a common finding. In set B rats, not only the males but also the females excreted protein in the urine. The method used to detect protein in the urine does not normally show a positive protein result in the young female rats. At the age of 3 months signs of chronic progressive nephrosis were observed in 55% of the males and in 15% of the females in set B. Two months later, the incidence had increased to about 70-80% in males and 50% in females. At 8 months, the incidence was similar, but the severity had increased. These values were compared with those obtained from the set A rats, none of which showed any signs of the disease at the age of 5 months and only 5% of the males and females at the age of 8 months. The results indicated that an increased excretion of protein in the urine may be used as an indicator for chronic progressive nephrosis in the rat and that not only the strain but also the source is important in selecting laboratory rats for toxicity studies.

Disease of the urinary system of commonly kept rodents: Diagnosis and treatment

Urinary-tract disease is relatively common in pet rodents. Diagnostic principles and management regimens for these species are essentially the same as those used for dogs and cats with urinary-tract disease. The most common disorders of the urinary system include urolithiasis in guinea pigs, chronic interstitial nephritis in aged gerbils, amyloidosis and arteriolar nephrosclerosis in hamsters, chronic progressive nephrosis in rats, and neoplasia in both mice and rats. Many of the disorders are more common in geriatric rodents and may present late in the course of the disease. Supportive care for renal failure in all species is similar: dietary restriction of protein and calcium, fluid therapy, unrestricted water, and husbandry changes to accommodate increased urine output.

Change of serum L-tryptophan levels following the development and recovery of acute puromycin aminonucleoside nephrosis in rats

It is known that total L-tryptophan (Trp) levels decrease with a decrease in albumin-bound Trp levels and an increase in free Trp levels in the plasma or serum of nephrotic children. We, therefore, examined the change of serum Trp levels following the development and recovery of acute nephrosis in 6-week-old male Wistar rats injected once with puromycin aminonucleoside (100mg/kg body weight) and checked the levels of 16 amino acids including Trp in the serum and the levels of Trp in the liver, kidney, and urine under nephrotic conditions. In this study, the development and recovery of nephrosis were checked by the changes of levels of urinary protein and serum protein and albumin. Total serum Trp and albumin-bound serum Trp levels decreased with the development of nephrosis and these decreased levels returned to the normal level with its recovery. In contrast, free serum Trp levels increased with the development of nephrosis and this increased level returned to the normal level with its recovery. In the serum of nephrotic rats, the decrease of albumin-bound Trp levels and the increase of free Trp levels were well consistent with a decrease in albumin levels and an increase in the level of non-esterified fatty acids which are known to weaken the binding of Trp to albumin and among 16 amino acids studied, only Trp showed a significant change in its levels. Trp levels increased in the liver and kidney but not in the urine under nephrotic conditions. These results indicate that the change of serum Trp levels should be closely related to the condition of nephrosis and that although serum Trp is lost under nephrotic conditions, the lost serum Trp is accumulated in the liver and kidney.

New aspects in the pathophysiology of aminonucleoside nephrosis in rats

The development of glomerulosclerosis represents a final common pathway leading to renal insufficiency. We have been studying several models of primary glomerular disease in rats or mice in an attempt to determine cellular and molecular mechanisms of glomerulosclerosis. These models include PAN nephrosis, lupus nephritis (NZB/W F1 mice), streptozotocin-induced diabetes, IgA nephropathy (ddY mice) and focal glomerulosclerosis.

Inhibition of progression of chronic puromycin aminonucleoside nephrosis by probucol, an antioxidant.

Oxidants have been shown to be involved in the initiation of chronic puromycin aminonucleoside nephrosis in rats, but it is uncertain whether they have a role in the progression of this disease. Rats given a single internal jugular venous bolus of puromycin aminonucleoside (PA) develop early nephrotic syndrome that subsides after about 28 days followed by a 4-wk period of minimal proteinuria and then the development of focal glomerulosclerosis and increasing proteinuria. Fifty-two rats on a high-cholesterol diet were divided into four groups. Two groups of 16 animals each received a single internal jugular venous bolus of PA. One of these groups was started on the dietary antioxidant, probucol (1% wt/wt), 4 days after the PA injection and continued on it until termination. The remaining rats were given an internal jugular venous injection of an equivolume of normal saline. Five of these animals were also started on dietary probucol 4 days after the saline injection. At 11 days postinjection all animals given PA, whether on probucol or not, developed marked proteinuria with histologically minimal glomerular change and significant increases in intraglomerular monocyte and proliferating cell nuclear antigen counts. Forty-two days after PA injection all PA-injected rats had minimal urinary protein injection and no glomerular changes. At 98 days postinjection rats given PA without probucol developed focal glomerulosclerosis and significant proteinuria compared with PA-injected rats on probucol and those injected with saline (P < 0.05). The probucol-fed PA-injected rats showed no glomerular disease and their urinary protein excretion rates were very similar to those of the saline controls. The results indicate that probucol inhibits the progression of chronic puromycin aminonucleoside nephrosis and are consistent with the suggestion that oxidants are involved in the progression of this entity.

The Possible Roles of Hyperlipidemia and Mononuclear Cells in Glomeruli in Puromycin Aminonucleoside Nephrosis in Rats

The possibility that hyperlipidemia and an increase of mononuclear cells in the glomeruli could participate in the pathogenesis of minimal change glomerulopathy was evaluated in puromycin aminonucleoside (PAN) nephrosis in rats. Significant increases in intraglomerular CD4-, IL-2-receptor (R)- and ED-1-positive cells were found in PAN rats. Urinary protein excretion and mononuclear cells in the glomeruli of 1% cholesterol diet-fed rats significantly increased, compared with standard diet feeding. Moreover, administration of a subnephrogenic dose of PAN in cholesterol diet-fed rats substantially increased urinary protein excretion and mononuclear cells in the glomeruli. Additionally, antihyperlipidemia agents and immunosuppressive agents prevented urinary protein excretion and increases of CD4-, IL-2R- and ED-1-positive cells in the glomeruli of PAN nephrotic rats. Monoclonal antibodies directed against these cells also prevented urinary protein excretion. These results suggest that CD4-, IL-2R- and ED-1-positive cells and hyperlipidemia are involved in the progression, but not the pathogenesis, of PAN.

Glomerular Expression of Smooth-Muscle Myosin Heavy-Chain Isoforms in Aminonucleoside Nephrosis in Rats

1. We investigated the glomerular expression of three types of myosin heavy-chain isoforms, including S-myosin heavy-chain 40 (SM1), S-myosin heavy-chain 29 (SM2) and FS-myosin heavy-chain 34 (SMemb) in puromycin aminonucleoside nephrosis. 2. There was little change in SM1 and SM2 mRNA levels throughout the experiment. In contrast, glomerular SMemb mRNA increased on days 2 and 4 (before and soon after the onset of proteinuria, respectively), but declined on day 8 (the peak of proteinuria). 3. Histological myosin heavy-chain expression was examined using three antibodies against SM1, SM2 and SMemb. Immunohistochemically, SM1 and SM2 were absent in the glomeruli associated with puromycin aminonucleoside nephrosis until day 20. The SMemb isoform was barely detectable in normal glomeruli, but substantial amounts of SMemb were demonstrated in the glomeruli of rats with puromycin aminonucleoside nephrosis. In the puromycin aminonucleoside-treated rats, the number of SMemb-positive glomerular cells increased on days 2 and 4. 4. We examined whether levels of alpha-smooth-muscle actin or proliferating cell nuclear antigen correlated with myosin heavy-chain levels in the glomeruli of rats with puromycin aminonucleoside nephrosis. None of the cellular components in the glomeruli was positive for either alpha-smooth-muscle actin or proliferating cell nuclear antigen in puromycin aminonucleoside nephrosis. 5. Administration of methylprednisolone to puromycin aminonucleoside-treated rats resulted in the rapid disappearance of proteinuria. However, methylprednisolone did not affect SMemb mRNA or immunostaining in a glomeruli of rats with puromycin aminonucleoside nephrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Are continuous therapies superior to intermittent haemodialysis for acute renal failure on the intensive care unit?

1. Ortiz A, Gomez-Chiarri M, Alonso J et al. The potential role of inflammatory and fibrogenic cytokines in the glomerular diseases. J Lipid Medial 1994; 9: 55-74 2. Ortiz A, Bustos C, Alonso J et al. Involvement of tumor necrosis factor-a in the pathogenesis of experimental and human glomerulonephritis. Adv Nephrol 1995 (in press) 3. Gomez-Chiarri M, Egido J, Emancipator S, Hamilton TA. Interferon-gamma and bacterial endotoxin induce IP-10 early gene expression in murine mesangial cells. Am J Pathol 1993; 142: 433-439 4. Ortiz A, Karp SL, Neilson EG. Clusterin (SGP2) mRNA expression by mesangial cells and its regulation by cytokines. J Am Soc Nephrol 1993; 4: 626 (A) 5. Gomez-Chiarri M, Ortiz A, Lerma JL, Mampaso F, Gonzalez E, Egido E. Involvement of tumor necrosis factor and platelet activating factor in the pathogenesis of experimental nephrosis in rats. Lab Invest 1994; 70: 449-459 6. Bertani T, Abbate M, Zoja C et al. Tumor necrosis factor-a induces glomerular damage in the rabbit. Am J Pathol 1989; 134:419-430 7. Tomosugi NI, Cashman SJ, Hay H et al. Modulation of antibody-mediated glomerular injury in vivo by bacterial lipopolysaccharide tumor necrosis factor and IL-1. J Immunol 1989; 142: 3083-3090 8. Mulligan MS, Johnson KJ, Todd RF et al. Requirements for 311

Modulation of cytoskeletal organization of podocytes during the course of aminonucleoside nephrosis in rats

By immunoelectron microscopy the modulation of cytoskeletal organization of podocytes during the course of puromycin aminonucleoside-induced nephrosis was examined. In control rats, tubulin and vimentin were present, limited to the podocyte cell body and the major processes. Their distribution in the foot processes was virtually negative. Myosin exhibited the same distribution pattern, albeit much more scattered, with no relation to any podocyte organelles or cell structures. Actin was scattered over the fibrillar zones of the cell body and its processes, including the foot processes. In proteinuric rats, loss of foot processes occurred and the glomerular basement membrane was covered by broad cytoplasmic sheets of podocytes, which contained these four subunits of cytoplasmic filaments. Accompanied by the disappearance of proteinuria, the structural organization of the foot processes was completely restored, in which tubulin, vimentin, and myosin were scarcely observed. Our results confirmed that the loss of foot processes is caused by their retraction, and indicated that the specific localization of the podocytic cytoskeleton contributes to the maintenance of the particular cell shape. Its reorganization may account for the structural modification of podocytes.

Effects of glycyrrhetinic acid on aminonucleoside nephrosis in rats

The effects of glycyrrhetinic acid (GA), an aglycon of glycyrrhizin extracted from the roots of Glycyrrhizae radix, on puromycin aminonucleoside (PA) nephrosis were studied in rats. Urine protein excretion in female rats (130 g-150 g) receiving PA (50 mg/kg) alone was significantly elevated on the 2nd day after injection of PA and reached a peak on the 14th day. Urinary protein on the 14th day was reduced to 74% in animals treated with GA (20 mg/kg) starting on the 2nd day after injection of PA. The increase in serum cholesterol and the decrease in serum protein were also suppressed by GA. Observation by electron microscopy revealed that the degree of abnormality in glomerular epithelial cells, i.e. loss or fusion of foot processes, was lower in the rats treated with GA after PA injection than in the rat treated with PA alone. Moreover, pretreatment with GA did not suppress urinary protein excretion but when it was given at the same time as PA and after PA a significant decrease in urinary protein excretion was observed.

Metabolic responses to nephrosis: effect of a low-protein diet.

To determine whether dietary protein restriction (LPD) causes protein catabolism in adriamycin nephrosis, nephrotic and control rats were paired by weight and gavage fed an 8.5% protein diet for 3 days (protocol 1) or 12 days (protocol 2). Fasting whole body protein turnover was then measured using a constant infusion of L-[1-14C]leucine. After 3 days of LPD, proteinuria decreased slightly and body weight did not change in either group. In contrast, leucine oxidation and urinary urea nitrogen excretion in nephrotic rats decreased by 18% and 37%, respectively (P < or = 0.05). After 12 days of LPD, weight loss did not differ between groups. In contrast to protocol 1, proteinuria decreased by 45% in nephrotic rats fed LPD for 12 days, and leucine oxidation rats increased to the level of control rats. Rates of whole body protein synthesis (PS) and degradation (PD) did not differ between nephrotic and control rats receiving LPD for 3 or 12 days, but were significantly lower than rates measured in rats fed 22% protein. We conclude that 1) proteinuria stimulates protein conservation even when dietary protein intake is restricted; 2) the decrease in amino acid oxidation was dependent on moderate proteinuria, since prolonged LPD ameliorated nephrosis and leucine oxidation rates increased to control levels; and 3) since weight loss and rates of whole body PS and PD in nephrotic and control animals were indistinguishable, moderate proteinuria did not increase protein catabolism.

In Vivo Protective Effect of Taurine on Puromycin Aminonucleoside-Induced Nephrosis in Rats.

The present investigation evaluated the effectiveness of taurine in attenuating the acute nephrosis in rats following intraperitoneal administration of puromycin aminonucleoside. Animals given a single injection of aminonucleoside (100mg/kg) developed nephrotic syndrome at the end of 10 days, as evidenced by heavy proteinuria, albuminuria, and increased urinary excretion of N-acetyl-β-D-glucos-aminidase when compared with the controls. Significant increases in kidney lipid peroxides, hydroxyl radicals, and hydroperoxides were also evident. Aminonucleoside significantly reduced the levels of glutathione, total thiol, ascorbic acid, and vitamin E in the kidney tissue. Significant reduction in the activities of antioxidant enzymes such as glucose-6-phosphate dehydrogenase, superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase were also observed in the nephrotic rats. Neither saline nor saline plus taurine treatment caused detectable changes in the above biochemical variables. Daily taurine administration to nephrotic rats for 10 days, however, reduced the severity of aminonucleoside-associated renal injury with significant reduction in urinary protein constituents, decreased lipid peroxides, and increased levels of antioxidants and antioxidant enzymes. Collectively, the results of this study demonstrate a protective role of taurine in ameliorating the acute nephrosis in response to puromycin aminonucleoside administration.

Angiotensin I converting enzyme activity in adriamycin induced nephrosis in rats

Activity of the dipeptidyl hydrolase angiotensin converting enzyme (ACE) has been observed to be altered by treatment with adriamycin (ADR). We used an animal model of ADR nephrotoxicity to study the effects on ACE in serum, urine and tissues on days 5, 10, 15, 20, 25 and 30 after ADR administration. Both glomerular and tubular injury occurred as evidenced by heavy proteinuria, albuminuria and increased urine N-acetyl glucosaminidase (NAG) excretion. Serum ACE was signifcaantly elevated on days 20, 25 and 30. Of great interest was the excretion of ACE in urine of treated rats which ran parallel with the total protein excretion above the barely detectable levels found in controls. ACE activity increased in kidney, adrenal gland and liver on days 15, 20, 25 and 30. Heart and brain ACE levels increased on days 25 and 30. Increased ACE activity in aorta and lungs occurred on days 20, 25 and 30. ACE activity decreased in kidney, aorta, heart and brain on days 5 and 10. These observations strongly suggest a contribution of various tissues to elevate the serum ACE level. Urinary ACE may be of potential use as an index for renal glomerular and tubular damage.

Altered glomerular steady-state levels of tumour necrosis factor-α mRNA during nephrotic and sclerotic phases of puromycin aminonucleoside nephrosis in rats

1. We determined glomerular and medullary tumour necrosis factor-alpha mRNA levels in acute puromycin aminonucleoside nephrosis on days 0, 8 and 20. 2. Tumour necrosis factor-alpha mRNA levels were increased fourfold in glomeruli and twofold in the medulla during the nephrotic stage of acute puromycin aminonucleoside nephrosis (day 8). 3. The high tumour necrosis factor-alpha mRNA levels in both glomeruli and the medulla were ameliorated significantly by methylprednisolone administration. 4. Focal glomerular sclerosis was induced in rats by injection of puromycin aminonucleoside on days 0, 27, 34 and 41 and by unilateral nephrectomy on day 22. 5. The percentage of sclerosing glomeruli was 16.6% on day 48 and had increased significantly to 72.8% on day 80. 6. During the sclerotic phase of puromycin amino-nucleoside nephrosis, glomerular tumour necrosis factor-alpha mRNA levels increased as glomerular sclerosis progressed. On day 80, glomerular tumour necrosis factor-alpha mRNA levels were 13-fold higher than levels in control rats. 7. These data suggest that glomerular tumour necrosis factor-alpha mRNA expression is associated with the development of puromycin aminonucleoside-induced glomerular sclerosis.

O-351 - Defective coupling of dopamine-1 receptor-adenylate cyclase system in kidney tubular membranes from nephrosis rats.

O-351 - Defective coupling of dopamine-1 receptor-adenylate cyclase system in kidney tubular membranes from nephrosis rats.

Possible mechanism of impaired calcium and vitamin D metabolism in nephrotic rats.

Patients who have nephrotic syndrome and normal renal function are hypocalcemic in spite of the elevated levels of serum parathyroid hormone (PTH) caused by a low serum concentration of 1,25-dihydroxyvitamin D[1,25(OH)2D], presumably because of its loss in urine. However, it has not been established whether the conversion of 25-hydroxyvitamin D[25(OH)D] into 1,25(OH)2D is impaired in the kidney. In this study, we examined the serum levels of vitamin D metabolites, and kinetics of renal 25(OH)D-1-hydroxylase activity in vitro, and nephrogenous cyclic AMP excretion in response to exogenous PTH administration in puromycin aminonucleoside-induced nephrosis in rats. Plasma ionized calcium and the serum levels of vitamin D metabolites were lower, and conversely, the serum PTH level was higher, in nephrotic rats than in controls. Serum 1,25(OH)2D levels were higher in 25(OH)D3-treated nephrotic rats than in untreated nephrotic rats, indicating that the low 1,25(OH)2D level in nephrotic rats is partially due to the low concentration of 25(OH)D. Although PTH levels were higher in nephrotic rats than in control rats, the Vmax of renal 25(OH)D-1-hydroxylase and nephrogenous adenosine 3',5'-monophosphate (cyclic AMP) excretion in response to exogenous PTH were significantly lower in nephrotic animals than in controls. These results suggest that abnormalities in calcium and vitamin D metabolism in nephrotic rats are partially attributable to impaired proximal tubular function.

Modulation of proteinuria and renal xanthine oxidase activity by dietary proteins in acute adriamycin nephrosis in rats: lack of correlation with intra- and extracellular amino acids.

Protein restriction ameliorates proteinuria in acute adriamycin (ADR) nephrosis and decreases the renal levels of xanthine oxidase (XO), a putative mediator of ADR nephrotoxicity. Hypothetically, the effect of protein restriction on renal XO levels may be due to variations in plasma and tissue proteic amino acids (AA). To elucidate this point, the levels of AA in plasma and in renal homogenates were determined in rats with ADR nephrosis and fed diets with different protein contents: (a) high (35%) casein; (b) standard (21%) casein; (c) low (9%) casein; (d) low casein plus a synthetic mixture of Val, Leu and Ile. The protein content of the diet determined certain marked variations in plasma AA: high levels of Val, Leu and Ile were found in rats fed on a high protein diet, while the same AA were low, in rats on low protein regimen. Supplementation of the low protein diet with a synthetic mixture of branched-chain AA (Val, Leu and Ile) normalized the plasma levels of these AA. In spite of these changes, tissue AA were similar in all groups, regardless of the protein contents of the diets. Furthermore, the levels of renal XO and proteinuria were unrelated to variations in plasma AA, since both parameters were low in protein-restricted and protein-restricted AA-supplemented rats while high in rats fed a high or normoproteic diet. These data demonstrate that low protein diets induce marked alterations in plasma AA composition which are similar in may respects to those found in protein malnutrition.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on the effectiveness of sairei-to on puromycin aminonucleoside nephrosis in rats.

In order to assess the effectiveness of sairei-to on nephrosis and to elucidate its mechanism of action, we made a puromycin aminonucleoside (PAN) rat model by a single intra-peritoneal injection of PAN at a dose of 100 mg/kg body weight (B.W.) and compared it to the normal controls. Sairei-to was administered in various doses (100,200,500 mg/kg B.W.) orally for 8 days after the initial injection of PAN. Proteinuria and serum triglyceride levels were significantly reduced in the sairei-to-treated groups showed a morphological improvement in the kidney over the PAN group. We found 500 mg/kg B.W. of sairei-to to be the most effective dose. The superoxide dismutase (SOD)-like activity was significantly elevated in the serum but not changed in the urine of sairei-to-treated groups pretreated with PAN. The normal control fed with 500 mg/kg B.W. of sairei-to showed a significant increase in serum SOD-like activity. The urinary prostanoid levels in the PAN group were lower than those in the normal and sairei-to-treated groups. These results support our hypothesis that sairei-to has effects on the elevation of SOD-like activity and on the synthesis of prostanoid in PAN-induced nephrosis, and that these effects are responsible for the mechanism of action of sairei-to.