RESUMO
PURPOSE:: To investigate the glomerular number after different warm ischemia times. METHODS:: Thirty two pigs were assigned into four groups. Three groups (G10, G20, and G30) were treated with 10, 20, and 30 minutes of left renal warm ischemia. The sham group underwent the same surgery without renal ischemia. The animals were euthanized after 3 weeks, and the kidneys were collected. Right kidneys were used as controls. The kidney weight, volume, cortical-medullar ratio, glomerular volumetric density, volume-weighted mean glomerular volume, and the total number of glomeruli per kidney were obtained. Serum creatinine levels were assessed pre and postoperatively. RESULTS:: Serum creatinine levels did not differ among the groups. All parameters were similar for the sham, G10, and G20 groups upon comparison of the right and left organs. The G30 group pigs' left kidneys had lower weight, volume, and cortical-medullar ratio and 24.6% less glomeruli compared to the right kidney. A negative correlation was found between warm ischemia time and glomerular number. CONCLUSIONS:: About one quarter of glomeruli was lost after 30 minutes of renal warm ischemia. No glomeruli loss was detected before 20 minutes of warm ischemia. However, progressive glomerular loss was associated with increasing warm ischemia time.
Assuntos
Córtex Renal/irrigação sanguínea , Glomérulos Renais/irrigação sanguínea , Rim/irrigação sanguínea , Isquemia Quente/efeitos adversos , Animais , Creatinina/sangue , Rim/fisiopatologia , Rim/cirurgia , Córtex Renal/fisiopatologia , Glomérulos Renais/fisiopatologia , Glomérulos Renais/cirurgia , Masculino , Modelos Animais , Distribuição Aleatória , Sus scrofa , Fatores de TempoRESUMO
Abstract Purpose: To investigate the glomerular number after different warm ischemia times. Methods: Thirty two pigs were assigned into four groups. Three groups (G10, G20, and G30) were treated with 10, 20, and 30 minutes of left renal warm ischemia. The sham group underwent the same surgery without renal ischemia. The animals were euthanized after 3 weeks, and the kidneys were collected. Right kidneys were used as controls. The kidney weight, volume, cortical-medullar ratio, glomerular volumetric density, volume-weighted mean glomerular volume, and the total number of glomeruli per kidney were obtained. Serum creatinine levels were assessed pre and postoperatively. Results: Serum creatinine levels did not differ among the groups. All parameters were similar for the sham, G10, and G20 groups upon comparison of the right and left organs. The G30 group pigs' left kidneys had lower weight, volume, and cortical-medullar ratio and 24.6% less glomeruli compared to the right kidney. A negative correlation was found between warm ischemia time and glomerular number. Conclusions: About one quarter of glomeruli was lost after 30 minutes of renal warm ischemia. No glomeruli loss was detected before 20 minutes of warm ischemia. However, progressive glomerular loss was associated with increasing warm ischemia time.
Assuntos
Animais , Masculino , Isquemia Quente/efeitos adversos , Rim/irrigação sanguínea , Córtex Renal/irrigação sanguínea , Glomérulos Renais/irrigação sanguínea , Fatores de Tempo , Distribuição Aleatória , Creatinina/sangue , Modelos Animais , Sus scrofa , Rim/cirurgia , Rim/fisiopatologia , Córtex Renal/fisiopatologia , Glomérulos Renais/cirurgia , Glomérulos Renais/fisiopatologiaRESUMO
AIMS: Adriamycin (ADR)-induced nephropathy is one of the most experimental models used in progressive kidney disease. A single dose of this drug induces a progressive and irreversible proteinuria that progresses to focal segmental glomerulosclerosis and tubulointerstitial lesions. Regular physical activity has been considered as a therapeutic intervention in several diseases. This study evaluated the influence of previous physical training in renal damage induced by ADR and the role of endothelial lesions and angiogenesis in this process. MAIN METHODS: Male Wistar rats were subjected or not to treadmill running for 4weeks and then injected with ADR (2.5mg/kg, i.v.) or saline. Twenty-four-hour urine samples were collected for albuminuria measurement, and blood samples were collected to measure plasma creatinine 60days after the injections. The kidneys were removed for histological, immunohistochemical, Western blot and ELISA studies. KEY FINDINGS: ADR-treated rats presented increases in plasma creatinine levels, albuminuria, podocyte damage, and enlargement of the tubular interstitial relative area, as well as higher macrophage numbers in the renal cortex, interleukin (IL)-1ß levels in renal tissue and urinary monocyte chemoattractant protein (MCP)-1, which were associated with reduction in vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS) expressions and peritubular capillary (PTC) density in renal cortex. These alterations were less intense in the animals subjected to previous exercise training. SIGNIFICANCE: Physical training prior to ADR injection reduced the renal damage induced by this drug. This effect was related to angiogenesis and reduction in the endothelial lesions and inflammatory process in the renal cortex of these animals.
Assuntos
Doxorrubicina , Córtex Renal/irrigação sanguínea , Córtex Renal/patologia , Nefropatias/induzido quimicamente , Nefropatias/prevenção & controle , Corrida , Albuminúria/induzido quimicamente , Albuminúria/patologia , Albuminúria/urina , Animais , Quimiocina CCL2/urina , Creatinina/sangue , Interleucina-1beta/análise , Rim/irrigação sanguínea , Rim/efeitos dos fármacos , Rim/patologia , Córtex Renal/efeitos dos fármacos , Nefropatias/patologia , Nefropatias/urina , Masculino , Óxido Nítrico Sintase Tipo III/análise , Podócitos/efeitos dos fármacos , Podócitos/patologia , Ratos Wistar , Fator A de Crescimento do Endotélio Vascular/análiseRESUMO
The purpose of this study was to investigate the ultrastructural effects of lead on the kidney cortex of rats. Wistar Albino rats (180-200g body weight) were divided into a controlled and lead acetate-exposed group. Rats received lead acetate at 500 ppm in their drinking water for 60 days. Both groups were fed with the same standard food, but lead acetate was added to the drinking water. During the experimental period, blood samples were taken from the abdominal aorta of the anesthetised animals. At the end of exposure, body weight and blood lead levels were measured. The kidney tissue samples were prepared and analyzed by light and transmission electron microscopy. Cortical renal tubules show various degenerative changes with focal tubular necrosis invaded by inflammatory cells. The ultrastructural alterations found in lead acetate-treated rats were a diminution in the amount of filtration slits, increased fusion of foot processes in epithelial cells of the glomeruli, increase of lysosomal structures and pinocytic vesicles as well as large mitochondria in proximal tubule cells.
El propósito de este estudio fue investigar los efectos ultraestructurales del plomo en la corteza renal. Ratas Wistar albinas (180-200g de peso corporal) fueron divididas en grupo control y grupo experimental. Las ratas recibieron 500 ppm de acetato de plomo en el agua potable durante 60 días. Ambos grupos fueron alimentados con el mismo alimento estándar, pero acetato de plomo se le añadió al agua potable al grupo experimental. Durante el período experimental, se tomaron bajo anestesia muestras sanguíneas desde la parte abdominal de la aorta. Al final de la exposición, fueron medidos el peso corporal y los niveles de plomo en la sangre. Fueron preparadas las muestras de tejido renal y se analizaron mediante microscopía de luz y electrónica de transmisión. Los túbulos renales corticales mostraron varios cambios degenerativos con necrosis tubular focal invadida por células inflamatorias. Las alteraciones ultraestructurales encontradas en las ratas tratadas con acetato de plomo correspondieron a una disminución en la cantidad de ranuras de filtración, aumento de la fusión de los procesos podales en las células epiteliales de los glomérulos, aumento de la estructura lisosomal y las vesículas pinocíticas, así como grandes mitocondrias en las células del túbulo proximal.
Assuntos
Ratos , Córtex Renal/anatomia & histologia , Córtex Renal , Córtex Renal/irrigação sanguínea , Córtex Renal/lesões , Córtex Renal/ultraestrutura , Chumbo/administração & dosagem , Chumbo/fisiologia , Chumbo/sangue , Chumbo/toxicidade , Acetatos/efeitos adversos , Acetatos/sangue , Acetatos/toxicidade , Ratos Wistar/anatomia & histologia , Ratos Wistar/lesões , Ratos Wistar/sangueRESUMO
OBJECTIVES: In a swine model of renal ischemia, we compared the effectiveness of the transurethral retrograde cold saline perfusion technique to the traditional method of renal cooling with ice slush, in achieving adequate parenchymal temperatures for functional preservation of the organ. Physiological and histological effects were also assessed. METHODS: Twenty-four domestic male pigs were sampled into four groups to be submitted to a 60-minute ischemia of the left kidney without cooling, with either one of the two cooling techniques (cold saline retrograde perfusion or ice slush), or sham surgery. All of them had also a concomitant right nephrectomy. Renal cortical and medullary temperatures were recorded throughout the experiment. Urinary output was measured, and serum renal function tests were carried on, pre- and postoperatively. After 5 days, the animals were euthanized and their kidneys were submitted to histological analysis. RESULTS: Mean renal temperature fell in both groups submitted to kidney cooling. With ice slush, a faster drop was observed and a lower minimum temperature was achieved (5.0 degrees C in the cortex and 6.3 degrees C in the medulla, vs. 25.4 degrees C and 24.9 degrees C with retrograde cooling). In the other groups, temperature was unchanged. Urinary output and serum creatinine worsened after the experiment, but without significant differences among groups. The histological analysis showed no differences among the four groups, for the studied ischemia time. CONCLUSIONS: Ice slush and retrograde perfusion of cold saline are both effective for cooling the kidney during ischemia. Ice slush is faster in doing so, and it allows much lower temperatures to be achieved in the renal parenchyma. With ischemia time of 60 minutes, no significant differences on the occurrence of functional and histological alterations were detected, even for the group without a cooling procedure.
Assuntos
Isquemia Fria/métodos , Rim/irrigação sanguínea , Rim/cirurgia , Modelos Animais , Suínos/cirurgia , Animais , Temperatura Corporal , Córtex Renal/irrigação sanguínea , Córtex Renal/cirurgia , Medula Renal/irrigação sanguínea , Medula Renal/cirurgia , Masculino , Resultado do TratamentoRESUMO
BACKGROUND: Despite the central role of Na(+), K(+)-ATPase (NKA) in ischaemic renal injury (IRI), cortical NKA activity values during renal ischaemia remain controversial. In this study, we explore why cortical NKA activity shows such behaviour during ischaemia in rats. METHODS: Ischaemia was induced by unilateral renal artery clamping (40 min, I) followed or not by reperfusion (60 min, IR). NKA alpha- and beta-subunit abundance was analysed by western blot. We studied the NKA detergent sodium dodecyl sulphate (SDS) enzymatic activation in isolated membrane preparations from control and ischaemic kidneys. RESULTS: NKA activity was diminished in I cortical homogenates (C = 9.3 +/- 1.1, I = 4.7 +/- 1.1* micromol Pi/h mg Prot, n = 4-6, *P < 0.05 versus C). This was rapidly recovered after reperfusion (IR = 9.9 +/- 1.2 micromol Pi/h mg Prot). alpha-subunit levels were increased, while beta-subunit was unchanged. At SDS 0.9 mg/ml (maximal detergent activation), the activities were indistinguishable (C = 90.5 +/- 2.2, I = 91.4 +/- 15.1 micromol Pi/h mg Prot). The analysis of detergent activation of NKA activity is widely used to estimate membrane leakiness in plasma membrane preparations. Our results suggest a higher population of sealed impermeable vesicles in preparations from ischaemic renal tissue. CONCLUSION: The well-known effect of ischaemia on renal cell cytoskeleton could explain the observed changes in the leakiness of membrane vesicles.
Assuntos
Córtex Renal/irrigação sanguínea , Córtex Renal/enzimologia , Traumatismo por Reperfusão/metabolismo , ATPase Trocadora de Sódio-Potássio/fisiologia , Vesículas Transportadoras/enzimologia , Animais , Masculino , Ratos , Ratos WistarRESUMO
This study was undertaken in anesthetized dogs to evaluate the relative participation of prostaglandins (PGs) and nitric oxide (NO) in the maintenance of total renal blood flow (TRBF), and renal medullary blood flow (RMBF). It was hypothesized that the inhibition of NO should impair cortical and medullary circulation because of the synthesis of this compound in the endothelial cells of these two territories. In contrast, under normal conditions of perfusion pressure PG synthesis is confined to the renal medulla. Hence PG inhibition should predominantly impair the medullary circulation. The initial administration of 25 microM kg-1 min-1 NG-nitro-L-arginine methyl ester produced a significant 26% decrease in TRBF and a concomitant 34% fall in RMBF, while the subsequent inhibition of PGs with 5 mg/kg meclofenamate further reduced TRBF by 33% and RMBF by 89%. In contrast, the initial administration of meclofenamate failed to change TRBF, while decreasing RMBF by 49%. The subsequent blockade of NO decreased TRBF by 35% without further altering RMBF. These results indicate that initial PG synthesis inhibition predominantly alters the medullary circulation, whereas NO inhibition decreases both cortical and medullary flow. This latter change induced by NO renders cortical and RMBF susceptible to a further decrease by PG inhibition. However, the decrease in medullary circulation produced by NO inhibition is not further enhanced by subsequent PG inhibition.
Assuntos
Córtex Renal/irrigação sanguínea , Medula Renal/irrigação sanguínea , Óxido Nítrico/fisiologia , Prostaglandinas/fisiologia , Animais , Bradicinina/farmacologia , Inibidores de Ciclo-Oxigenase/farmacologia , Cães , Córtex Renal/efeitos dos fármacos , Medula Renal/efeitos dos fármacos , Masculino , Ácido Meclofenâmico/farmacologia , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico/antagonistas & inibidores , Antagonistas de Prostaglandina/farmacologia , Fluxo Sanguíneo Regional/efeitos dos fármacos , Vasodilatadores/farmacologiaRESUMO
This study was undertaken in anesthetized dogs to evaluate the relative participation of prostaglandins (PGs) and nitric oxide (NO) in the maintenance of total renal blood flow (TRBF), and renal medullary blood flow (RMBF). It was hypothesized that the inhibition of NO should impair cortical and medullary circulation because of the synthesis of this compound in the endothelial cells of these two territories. In contrast, under normal conditions of perfusion pressure PG synthesis is confined to the renal medulla. Hence PG inhibition should predominantly impair the medullary circulation. The initial administration of 25 µM kg-1 min-1 NG-nitro-L-arginine methyl ester produced a significant 26 percent decrease in TRBF and a concomitant 34 percent fall in RMBF, while the subsequent inhibition of PGs with 5 mg/kg meclofenamate further reduced TRBF by 33 percent and RMBF by 89 percent. In contrast, the initial administration of meclofenamate failed to change TRBF, while decreasing RMBF by 49 percent. The subsequent blockade of NO decreased TRBF by 35 percent without further altering RMBF. These results indicate that initial PG synthesis inhibition predominantly alters the medullary circulation, whereas NO inhibition decreases both cortical and medullary flow. This latter change induced by NO renders cortical and RMBF susceptible to a further decrease by PG inhibition. However, the decrease in medullary circulation produced by NO inhibition is not further enhanced by subsequent PG inhibition.
Assuntos
Animais , Cães , Masculino , Córtex Renal/irrigação sanguínea , Medula Renal/irrigação sanguínea , Óxido Nítrico/fisiologia , Prostaglandinas/fisiologia , Bradicinina/farmacologia , Inibidores de Ciclo-Oxigenase/farmacologia , Córtex Renal/efeitos dos fármacos , Medula Renal/efeitos dos fármacos , Ácido Meclofenâmico/farmacologia , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico/antagonistas & inibidores , Antagonistas de Prostaglandina/farmacologia , Fluxo Sanguíneo Regional/efeitos dos fármacos , Vasodilatadores/farmacologiaRESUMO
BACKGROUND/AIMS: The knowledge of molecular mechanisms determining drug pharmacokinetics in pathological states is relevant for the development of new therapeutic approaches. This study was undertaken to evaluate the cortical renal blood flow (cRBF) and the renal protein expression of the organic anion transporters (OAT1 and OAT3) in association with the elimination of organic anions in an early stage of renal ischemia-reperfusion. METHODS: Ischemic acute renal failure (ARF) was induced in adult male Wistar rats by occlusion of both renal pedicles during 60 min, followed by 60 min of reperfusion (ARF group). Pair-fed sham-operated rats served as controls. The renal protein expression of OAT1 and OAT3 was evaluated by immunohistochemistry techniques and by Western blotting in renal cortex homogenates and in basolateral plasma membranes. A pharmacokinetic study of p-aminohippurate (PAH, a prototypical organic anion) was performed. cRBF was determined using fluorescent microspheres. RESULTS: ARF rats displayed a significant decrease in systemic clearance and in renal excretion of PAH. OAT1 and OAT3 protein abundance showed a statistically significant reduction both in homogenates and in basolateral plasma membranes from ARF rats. Immunohistochemical studies confirmed the changes in the cortical renal expression of these transporters. ARF animals also showed a decrease in cRBF. CONCLUSIONS: The decrease in PAH elimination observed in an early stage of renal ischemia-reperfusion in male Wistar rats might be explained by the sum of the lower OAT1 and OAT3 expression in renal basolateral plasma membranes plus the decrease in cRBF. These findings might have significant implications in the development of novel pharmacological strategies to be applied in the initial stages of ischemic ARF.
Assuntos
Membrana Celular/fisiologia , Córtex Renal/irrigação sanguínea , Córtex Renal/metabolismo , Proteínas de Membrana Transportadoras/fisiologia , Transportadores de Ânions Orgânicos/metabolismo , Circulação Renal/fisiologia , Traumatismo por Reperfusão/metabolismo , Injúria Renal Aguda/genética , Injúria Renal Aguda/metabolismo , Animais , Membrana Celular/genética , Masculino , Proteínas de Membrana Transportadoras/deficiência , Proteínas de Membrana Transportadoras/genética , Transportadores de Ânions Orgânicos/deficiência , Transportadores de Ânions Orgânicos/genética , Ratos , Ratos Wistar , Traumatismo por Reperfusão/genéticaRESUMO
BACKGROUND: Chronic renal damage is associated with inflammatory infiltration, fibrosis and vascular lesion, coupled with increased expression of cyclo-oxygenase 2 (COX-2) and transforming growth factor-beta1 (TGF-beta1). However, the role of inducible nitric oxide synthase (NOS-2) is still controversial. Thus, we studied the contribution of NOS-2 to the expression levels of COX-2 and TGF-beta1, as well as the structural renal injury in rats with subtotal renal ablation (5/6 Nx). METHODS: Four groups of rats were studied: sham, 5/6 Nx, 5/6 Nx+aminoguanidine (AG) and 5/6 NX+L-NIL (L-N6-iminoethyl-lysine). Systolic blood pressure (SBP), proteinuria and creatinine (Cr) clearance were measured. NOS-2, COX-2 and TGF-beta1 gene expression was determined by real-time reverse transcription-polymerase-chain reaction. Protein expression was evaluated by western blot and ELISA (TGF-beta1). Immunohistochemistry and morphometry were performed for NOS-2, microvascular thickening and fibrosis. RESULTS: Systemic hypertension and marked proteinuria, increased expression of NOS-2, COX-2 and TGF-beta1, thickening of arteriolar wall and tubulointerstitial fibrosis were produced in 5/6 Nx rats. Chronic inhibition of NOS-2 did not prevent arterial hypertension or the fall in Cr clearance, but partially reduced proteinuria. Nevertheless, AG and L-NIL preserved arteriolar morphology and the administration of both selective inhibitors of inducible NOS (AG and L-NIL) prevented NOS-2 overexpression. CONCLUSION: This study shows that NOS-2 was markedly enhanced in renal tissue of 5/6 Nx rats. Moreover, treatment with AG and L-NIL prevented the morpho-functional changes induced by subtotal renal ablation, despite persistence of systemic hypertension, suggesting that high concentrations of nitric oxide produced by NOS-2 could act as a positive modulator of the proinflammatory and profibrotic pathways involved in the progression of renal disease.