Allograft Nephropathy In Rats Research Articles

Early treatment with xenon protects against the cold ischemia associated with chronic allograft nephropathy in rats

Chronic allograft nephropathy (CAN) is a common finding in kidney grafts with functional impairment. Prolonged hypothermic storage-induced ischemia-reperfusion injury is associated with the early onset of CAN. As the noble gas xenon is clinically used as an anesthetic and has renoprotective properties in a rodent model of ischemia-reperfusion injury, we studied whether early treatment with xenon could attenuate CAN associated with prolonged hypothermic storage. Exposure to xenon enhanced the expression of insulin growth factor-1 (IGF-1) and its receptor in human proximal tubular (HK-2) cells, which, in turn, increased cell proliferation. Xenon treatment before or after hypothermia-hypoxia decreased cell apoptosis and cell inflammation after reoxygenation. The xenon-induced HK-2 cell proliferation was abolished by blocking the IGF-1 receptor, mTOR, and HIF-1α individually. In the Fischer-to-Lewis rat allogeneic renal transplantation model, xenon exposure of donors before graft retrieval or recipients after engraftment enhanced tubular cell proliferation and decreased tubular cell death and cell inflammation associated with ischemia-reperfusion injury. Compared with control allografts, xenon treatment significantly suppressed T-cell infiltration and fibrosis, prevented the development of CAN, and improved renal function. Thus, xenon treatment promoted recovery from ischemia-reperfusion injury and reduced susceptibility to the subsequent development of CAN in allografts.

Chronic Allograft Nephropathy in Rats Is Improved by the Intervention of Rhein

AimIn this study, we investigated the therapeutic efficacy and potential mechanisms of rhein to mitigate chronic allograft nephropathy (CAN) in rats. Materials and MethodsFisher rat donors and Lewis rat recipients were used to establish the CAN model. Thirty rats with transplanted kidneys were randomly divided into two groups: 16 untreated and 14 rhein = treated rats. Five Lewis rat controls underwent removal of their right kidneys. The Intervention group was administered rhein oral solution (100 mg kg-1 d-1) by gavage after transplantation. The untreated and control groups were given 0.5% sodium carboxymethyl cellulose. Blood and urine samples were collected at 4, 8, and 16 weeks to examine renal function and total urine protein. Half of the rats in each group were sacrifice at 8 or 16 weeks to examine renal pathology. Immunohistochemical examination and real-time polymerase chain reaction of renal tissues were performed to detect expressions of transforming growth-β1(TGF-β1), hepatic growth factor (HGF), bone morphogenetic protein 7 (BMP7), frobronectin, and collgen IV. ResultsRhein improved renal function and significantly reduced renal fibrosis and interstitial inflammation. The levels of BMP7 and HGF were significantly elevated in the renal tissues of the rhein intervention group. In the meantime, fibronectin and collagen IV were decreased in the extracellular matrix. The expression of TGF-β1 was similar between these two groups. ConclusionRhein improved renal function and reduced renal fibrosis and interstitial inflammation by inducing production of HGF and BMP7.

Effect of Spironolactone on Chronic Allograft Nephropathy in Rats

Objective: Chronic allograft nephropathy (CAN) is common following renal transplantation in cats and people. Aldosterone potentiates ongoing renal injury; however its role in CAN is less defined. Spironolactone, an aldosterone receptor blocker, is protective in other rodent models of renal injury. The purpose of this study was to evaluate spironolactone on the development of CAN in a rat model Animals: Fisher and Lewis, adult, male rats. Procedures: A Lewis to Fisher model of CAN was used. Rats were divided into 4 groups, 2 nephrectomy controls (CON) and 2 transplantation (TX) groups. Two groups (a CON and TX) received tap water (0.25 ml/day orally), and the remaining 2 received spironolactone (10 mg/kg orally) daily for 16 weeks post transplantation. Serum creatinine concentration, urine-protein: urine-creatinine (UP: UC), and changes in renal cortex gene expression were measured during and at 16 weeks after transplantation. Results: There were no significant differences in any of the outcome measures when the 2 TX groups were compared. TX rats had significantly more (p=0.0002) histological lesions consistent with CAN and elevation in TNF-α (p=0.0402) compared to CON animals. Conclusions and clinical relevance: In this study, spironolactone did not protect against the development or progression of CAN. Impact for human medicine: The impact of aldosterone on the occurrence of CAN in humans following renal transplantation remains an area of investigation.

Therapeutic effect of low-dose aspirin on chronic allograft nephropathy in renal recipient rats

Objective To observe the effect of low-dose aspirin on allogeneic chronic allograft nephropathy in renal recipient rats and the possible mechanisms.Methods Chronic allograft nephropathy model of rats were established and the recipient rats were randomly divided into 2 groups with 10 in each group.Cyclosporine A (5 mg/kg) was administered as a basic treatment one day before surgery to prevent and treat acute rejection.Aspirin therapy group was given oral aspirin (5 mg/kg) daily,and control group were given oral saline 2 ml/d.Animals were sacrificed 8 weeks after operation and the serum creatinine,urea nitrogen levels were determined.Renal histomorphology and immunohistochemistry approaches were used to examine TGF-β1 expression.Results The severity of pathological lesion,increase of serum creatinine and blood urea nitrogen levels,and expression of fibrosis associated factor TGF-β1 in aspirin therapy group were significantly slighter than those of the saline control group(P0.05).Conclusion Low-dose aspirin in addition to routine anti-rejection treatment can be used for treatment of chronic allograft nephropathy in rats,which might be associated with the decreased expression of anticoagulation factor TGF-β1.

Therapeutic Effect of Y-27632 on Chronic Allograft Nephropathy in Rats

Chronic allograft nephropathy (CAN) is a major cause of late allograft loss. Recent evidences suggest that Rho and its downstream effector ROCK may be greatly involved in the progression of renal fibrosis. Inhibition of Rho/ROCK pathway might interact with the inflammatory process in the renal interstitium, and antagonize the process of epithelial-to-mesenchymal transition (EMT). We hypothesized that Y-27632 could inhibit the chronic inflammatory process and prevent the progression of CAN. Fisher (F344) kidneys were orthotopically transplanted into Lewis rat recipients. Lewis to Lewis rat kidney transplantation was served as the syngeneic control (Syn group). Allograft recipients were randomized and treated with either cyclosporine A alone (Allo group), or in combination with Y-27632 (30 mg/kg body weight/d intragastric, Y-27632 group). Renal function and urine protein excretion levels of the rats were analyzed. Animals were sacrificed 12 wk post-transplantation for histological and immunohistochemical studies, as well as analysis of the expression levels of chemokines, transforming growth factor (TGF-beta) 1 and alpha smooth muscle actin (alpha-SMA). Renal function deteriorated progressively in the Allo group, and there was typical CAN morphology in the kidneys. However, Y-27632-treatment significantly prevented the deterioration of graft function, lessened the level of urine protein excretion, and preserved the renal structure. Attenuation of ED1 positive mononuclear cell infiltration and amelioration of tubulointerstitial fibrosis were achieved by Y-27632 intervention. This was associated with down-regulation of the expression of tubular monocyte chemoattractant protein-1, RANTES (regulated upon expression normal T cell expressed and secreted), and phosphorylated NF-kappaB (which was a marker for activation). Profibrotic protein (TGF-beta1) and alpha-SMA, a marker of EMT, were significantly down-regulated by Y-27632 treatment as well. The Rho/ROCK pathway plays an important role in the progression of CAN, and specific inhibition of Rho activity by Y-27632 showed favorable effects on blocking renal interstitial inflammation and fibrosis, thus efficiently retarding the development of CAN, which might provide us with a novel strategy to improve long-term renal graft survival.

C4d Deposition Is Associated With Chronic Allograft Nephropathy in Rats and Could Be Influenced by Immunosuppressants

Aims Deposition of C4d in peritubular capillaries (PTC) has been considered to be a marker of humoral immunity in renal transplant. This study is to investigate C4d deposition in rat renal allografts undergoing CAN and the effects of immunosuppressants on it. Methods Fisher 344 rat renal grafts were orthotopically transplanted into Lewis rats following the procedure of Kamada with our modification. All the recipients were given CsA 10 mg/kg −1 · d −1 × 10 d and then divided into 5 groups (each n = 9); (1) Vehicle: vehicle orally, (2) CsA: 6 mg/kg −1 · d −1, (3) RAPA: 0.8 mg/kg −1 · d −1, (4) FK 506: 0.15 mg/kg −1 · d −1, (5) MMF: 20 mg/ kg −1 · d −1. At 4 weeks, 8 weeks, 12 weeks, the rats were sacrificed, renal allografts were harvested and sera were collected. The deposition of C4d was detected by immunofluorescence and analyzed by Integrated Optical Density (IOD). The pathological changes were accessed according to the Banff 97 criteria. Results C4d deposition in PTC was found in all the allografts at 4 weeks, while there was no obvious manifestations of CAN in all the groups; the differences of Banff Score between all groups were not significant ( P > .05). The values of IOD in RAPA and MMF group were lower than those in other 3 groups ( P = .002, .006). The differences between RAPA and MMF, and between other 3 groups were not significant ( P > .05). The intensity of C4d increased along with the progression of CAN, the heaviest C4d deposits in PTC were found at 12 weeks, and meanwhile the severest CAN was found. Comparing with Vehicle group, CsA and FK 506 had no effect on C4d deposition ( P > .05), however, MMF and RAPA obviously decreased the C4d deposition ( P = .000). The intensity of C4d deposition had a significant correlation with the severity of CAN ( r = 0.894, P = .000). Conclusions Our study suggests that the deposition of C4d in allografts appears earlier than pathological changes of CAN and has a correlation with the progression of CAN. MMF and RAPA can attenuate CAN by inhibiting humoral immunity. In contrast, CsA and FK 506 have no effect on humoral immunity.

SDF-1 Plays a Key Role in Chronic Allograft Nephropathy in Rats

Objectives Our previous study demonstrated that anti-stromal cell derived factor-1 (SDF-1) antibody delayed graft arteriosclerosis in rat abdominal aortic grafts. In this study, we investigated the mechanisms of SDF-1 on chronic allograft nephropathy (CAN), and whether SDF-1 antibody had protective effect on CAN. Methods Male Lewis rats that received left renal grafts from male Fisher 344 rats were randomly divided into three groups: group A only received cyclosporine (CsA; 10 mg · kg −1 · d −1) every day; group B received anti–SDF-1 antibody (8 μg · kg −1 · d −1) + CsA (10 mg · kg −1 · d −1); and group C, an isograft control (Fisher 344 to Fisher 344). All recipient animals were unilaterally right nephrectomized. Group A and B grafts were preserved in 4°C UW solution for 1 hour prolonged cold ischemia. Masson and hematoxylin and eosin staining were performed to evaluate glomerular sclerosis rate (GSR) and Banff score. Serum creatinine (Scr) and blood urea nitrogen (BUN) were determined as well as histologic examinations of the kidneys with immunohistochemistry for SDF-1 and CXCR4, the only known receptor of SDF-1. Results Compared with group C, ischemia and rejection produced a nine-fold increase in GSR and Banff score, as well as significant increases in Scr and BUN levels in group A. Anti–SDF-1 antibody retarded the increase by downregulating the expression of SDF-1 and CXCR4. Furthermore, there was a significant relationship between the expression of SDF-1 and the mean Banff score. Conclusion Anti–SDF-1 antibody retarded the process of CAN.

Effect of Ligustrazine on Chronic Allograft Nephropathy in Rats

Objectives Our previous study demonstrated that Ligustrazine reduced renal dysfunction associated with ischemia-reperfusion injury in mice. In this study, we investigated whether Ligustrazine herbal injection had any preventive and therapeutic effectiveness against chronic allograft nephropathy in rats. Methods Male Lewis rats that received left renal grafts from male Fisher 344 rats were randomly divided into five groups: group A only received cyclosporine (CsA; 10 mg · kg −1 · d −1) every day. Groups B, C, and D received low-dose Ligustrazine (50 mg · kg −1 · d −1) + CsA (10 mg · kg −1 · d −1); high-dose Ligustrazine (100 mg · kg −1 · d −1) + CsA (10 mg · kg −1 · d −1); and CsA (10 mg · kg −1) + mycophanolate mofetil (10 mg · kg −1 · d −1), respectively. Group E was an isografted group (Fisher 344 to Fisher 344). Grafts were preserved in 4°C University of wisconsin solution for 1 hour prolonged cold ischemia. All recipient animals were unilaterally right nephrectomized. Serum creatinine (Scr), blood urea nitrogen (BUN), urinary protein, kidney malondialdehyde (MDA) level, and superoxide dismutase (SOD) were determined, as well as examining kidney histology with immunohistochemistry for Bcl-2, and ICAM-1. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were tested to show whether Ligustrazine has side effects. Results Compared with group E, ischemia and rejection produced a ninefold increase in GSR and Banff score, as well as significant increases of Scr, BUN, and urinary protein levels in group A. High doses of Ligustrazine significantly slowed the increase ( P < .01). Ligustrazine also decreased MDA levels and ameliorated the down-regulation of SOD activity. Bcl-2 was up-regulated posttransplantation, especially in the Ligustrazine-treated group ( P < .01). The up-regulation of ICAM-1 was greatly diminished by Ligustrazine ( P < .01). Furthermore, there was little difference in ALT/AST between the Ligustrazine-treated and the isograft group. Conclusion These findings suggested that Ligustrazine could postpone chronic renal allograft dysfunction associated with cold ischemia injury and chronic allograft rejection but had no evident hepatic side effects.

Renoprotective effects of the AGE-inhibitor pyridoxamine in experimental chronic allograft nephropathy in rats

Advanced glycation end products (AGEs) are involved in diabetic nephropathy (DN). The AGE formation inhibitor pyridoxamine (PM) is renoprotective in DN and in normoglycaemic obese Zucker rats. In chronic allograft nephropathy (CAN), renal AGE accumulation occurs as well. To investigate whether inhibition of AGE formation is renoprotective in CAN, we studied the Fisher 344 to Lewis (F-L) allograft rat model of experimental CAN. Fisher to Fisher (F-F) isografts served as controls. Proteinuria, renal function and renal histology of untreated transplanted rats (F-L n = 8, F-F n = 8) were compared to rats receiving PM 2 g/l in drinking water for 20 weeks starting at transplantation (F-L n = 5, F-F n = 10). All rats received cyclosporin A (1.5 mg/kg/day) for 10 days after transplantation to prevent early acute rejection. Compared to untreated allografts, PM significantly decreased proteinuria (76 +/- 18 vs 29 +/- 3 mg/day), serum creatinine (130 +/- 12 vs 98 +/- 5 micromol/l), focal glomerulosclerosis (116 +/- 27 vs 16 +/- 5 AU), glomerular macrophage influx (5.6 +/- 0.6 vs 3.3 +/- 1.0), interstitial fibrosis (132 +/- 24 vs 76 +/- 2 AU) and interstitial macrophage influx (47.0 +/- 8.7 vs 15.4 +/- 5.0. Moreover, PM significantly ameliorated tubular accumulation of pentosidine, compared to untreated allografts (2.5 +/- 0.6 vs 0.3 +/- 0.3, all p < 0.05). In the isograft controls, these values did not differ between untreated and PM treated rats. PM exerts renoprotective effects and decreases renal pentosidine accumulation in experimental CAN, suggesting a detrimental role for renal AGE accumulation in the pathogenesis of renal damage in this non-diabetic model. These results indicate that inhibition of AGE formation might be a useful adjunct therapy to attenuate CAN.

Cytomegalovirus enhance expression of growth factors during the development of chronic allograft nephropathy in rats

Cytomegalovirus (CMV) accelerates chronic rejection (CRX) in a model of rat kidney allograft. In this model, the expressions of transforming growth factor beta 1 (TGF-beta), platelet-derived growth factor (PDGF)-AA, PDGF-BB and connective tissue growth factor (CTGF) were investigated with and without CMV. Transplantations were performed under immunosuppression. One group of animals was infected with CMV and the other was left uninfected. The grafts were harvested on days 3-60 after transplantation. Growth factor proteins were demonstrated by immunohistochemistry, and mRNAs by in situ hybridization. A significantly more intense and earlier endothelial TGF-beta (2.4 +/- 0.8 vs. 1.0 +/- 0.0; P < 0.05) and PDGF-AA (1.8 +/- 0.4 vs. 1.0 +/- 0.0; P < 0.05) expressions, confirmed by mRNA hybridization, occurred in the CMV group compared with the noninfected group. PDGF-BB appeared in a few inflammatory cells only. In addition CTGF appeared earlier and has more intense in the CMV group (2.5 +/- 0.6 vs. 1.2 +/- 0.5) and the number of CTGF mRNA-positive fibroblasts (57 +/- 9 vs. 3 +/- 4; P < 0.05) was significantly higher. Thus, CMV enhanced expression of TGF-beta1, PDGF-AA and CTGF during the development of CRX.

Inhibition of Matrix Metalloproteinases During Chronic Allograft Nephropathy in Rats

Chronic allograft nephropathy (CAN) belongs to the major causes of long-term kidney allograft failure. One of the histologic hallmarks of CAN is interstitial fibrosis, influenced by matrix metalloproteinases (MMPs) that are controlling extracellular matrix (ECM) degradation. Whether MMPs affect the development and progression of CAN is not clear so far. To analyze the role of MMPs in CAN, we investigated the effects of an early and a late application of BAY 12-9566, an inhibitor of MMP-2, -3, and -9 on the development and progression of CAN in a rat kidney-transplantation model. Fisher kidneys were orthotopically transplanted into Lewis recipients that were treated with BAY 12-9566 (15 mg/kg per day) or vehicle either for the first 10 days after transplantation (early treatment) or from week 12 to week 20 after transplantation (late treatment). Proteinuria was analyzed every 4 weeks up to week 20 after transplantation when kidney grafts were removed for further analysis. Early MMP-inhibition resulted in a significantly reduced 24-hour protein excretion that was paralleled by a lower grade of CAN after 20 weeks. However, late MMP inhibition starting at week 12 after transplantation resulted in significantly higher proteinuria and a higher grade of CAN as compared with controls. Furthermore, transforming growth factor-beta and platelet-derived growth factor-B chain mRNA levels were significantly increased in these animals. Inhibition of MMPs early after transplantation reduced the development and progression of CAN but promoted CAN if initiated at later stages. Thus, MMPs are involved in the development and progression of CAN.

Oxidative stress in chronic renal allograft nephropathy in rats: effects of long-term treatment with carvedilol, BM 91.0228, or alpha-tocopherol.

Oxidative stress is markedly increased after kidney transplantation and may participate in the development and/or progression of chronic renal allograft nephropathy. In the present study we sought to assess the nephroprotective potential of antioxidative treatment in renal allograft recipients. Experiments were performed in the Fisher-Lewis rat model of chronic renal allograft nephropathy, with isografted Lewis rats serving as controls. Allografted rats were orally treated with carvedilol, an antihypertensive drug with antioxidative properties (25 mg/kg/d), its purely antioxidative derivative BM 91.0228 (5 mg/kg/d), alpha-tocopherol (100 mg/kg/d), a combination of propranolol/doxazosine (10/5 mg/kg/d), or vehicle for 24 weeks. At the end of the study, oxidative status and influence of antioxidative treatment were assessed in transplanted animals. Chronic allograft nephropathy was characterized by a marked increase of markers for oxidative stress (increased plasma and kidney levels of malondialdehyde, reduced glutathione, and tocopherol levels in renal allografts). Treatment with carvedilol, BM 91.0228, and tocopherol significantly improved antioxidative status of allograft kidney recipients. In addition, carvedilol reduced elevated blood pressure in allografted rats. However none of the drugs had a beneficial influence on functional and morphologic renal changes. Our data thus demonstrate that long-term treatment with the antioxidants carvedilol, BM 91.0228, or alpha-tocopherol does not prevent development of chronic transplant nephropathy, despite an improvement of antioxidative status.

The involvement of activated T cells and growth-factor production in the early and late phase of chronic kidney allograft nephropathy in rats

T cells are thought to play a regulatory role in chronic allograft nephropathy (CAN). Thus, we investigated whether lymphocyte inhibition influences CAN. Fisher rat (F-344) kidneys were transplanted orthotopically into Lewis rats. Animals received cyclosporin A (1.5 mg/kg per day, s.c.) for 10 days and were treated daily with either cyclosporin A (1.5 mg/kg), tacrolimus (0.16 mg/kg), or a vehicle thereafter ( n=15 per group). Kidneys were harvested at 16 or 24 weeks. Interleukin-2 (IL-2) and interleukin-2 receptor beta (IL-2Rbeta) mRNA synthesis were intense at 16 weeks and decreased thereafter. Unsurprisingly, both cyclosporin A and tacrolimus significantly inhibited IL-2 and IL-2Rbeta at both time points. Proteinuria increased more rapidly in controls than in treated animals. Morphologically, over 40% of glomeruli were sclerosed by 16 weeks in controls, and ED-1+ macrophages and CD5+ T cells infiltrated the graft. IL-2 mRNA synthesis paralleled the number of infiltrating cells. Inhibition of T-cell proliferation significantly reduced glomerulosclerosis and leukocyte infiltration at both time points. Transforming growth factor (TGF)-beta(1) and platelet-derived growth factor (PDGF) synthesis were highly upregulated in controls at 16 weeks, the time of peak infiltration. At 24 weeks, as cellular infiltration was replaced by scar formation, TGF-beta(1) mRNA returned to normal, while PDGF did not. Inhibition of T cells prevented the upregulation of TGF-beta(1) at both time points; however, PDGF was suppressed only at week 16. These results indicate a beneficial effect of continuous suppression of T cells in CAN. T cells are probably more important in the early, inflammatory phase.

Recipient age affects chronic allograft nephropathy in rats

Recipient age affects chronic allograft nephropathy in rats

Increased dietary salt accelerates chronic allograft nephropathy in rats

Chronic allograft nephropathy (CAN), a major problem in renal transplantation, is related to both alloantigen-dependent and -independent processes. Because dietary salt intake modulated glomerular production of transforming growth factor-beta, which has been shown to play an important role in CAN, we hypothesized that dietary salt would directly enhance renal injury in a rodent model of CAN. Dietary NaCl was increased from 1.0% (normal) to 8.0% in a group of Fisher/Lewis rats 25 days following orthotopic renal transplantation and was continued until 16 weeks after transplantation. Blood pressure, which was recorded using radiotelemetry in the first eight-weeks post-transplantation, did not differ between the groups, but allograft recipients on the 8.0% NaCl diet rapidly demonstrated increased urinary albumin excretion. Renal function determined by dynamic functional imaging was worse in allograft recipients on the 8.0% NaCl diet by six weeks following transplantation. Histologic examination at 16 weeks confirmed a significant increase in allograft damage in the 8.0% NaCl group compared with allografts from rats on 1.0% NaCl diet. These findings included glomerulosclerosis and tubulointerstitial injury that consisted of fibrosis, tubular atrophy and dilation, intratubular casts, and tubular epithelial cell damage. Small arteries and arterioles did not show evidence of damage from hypertension or other abnormality. In this model of CAN, renal allograft dysfunction preceded hypertension and was accelerated significantly by an increase in dietary salt.

Increased dietary salt accelerates chronic allograft nephropathy in rats

Increased dietary salt accelerates chronic allograft nephropathy in rats