RESUMEN
The process of regenerating liver is the result of a balance between stimulating factors and inhibitors of hepatocyte proliferation. Melatonin and its metabolites have been found to protect tissues against oxidative damage generated by a variety of toxic agents and metabolic processes. Furthermore, studies in liver of rats showed a decrease in the liver mitochondrial hydroxylation of drugs returning to the normal state after the administration of antioxidants. This study was designed to determine, in experimental animals, whether the administration of an antioxidant agent such as melatonin could prevent cells events leading to tissue injury and hepatic dysfunction after partial hepatectomy (PH). Biliary flow (BF), oxidative stress in hepatic tissue and Naâº/K⺠ATPase activities in whole plasma membrane were determined. PH decreased the Naâº/K⺠ATPase activity. PH significantly reduced the BF (36%) and promoted oxidative stress with an increase of lipoperoxidation and decrease of glutathione peroxidase and catalase activities. Treatment with melatonin prevented the decrease of BF in rats with hepatectomy and normalized the Naâº/K⺠ATPase activity. Moreover, melatonin markedly attenuated oxidative stress produced by PH. This may be the results of the higher efficacy of melatonin in scavenging various free radicals and also because of its ability in stimulating the antioxidant enzymes. We suggest that oxidative stress before and during liver regeneration has a crucial role in cholestasis, apoptotic/necrotic hepatocellular damage and the impairment in liver transport function induced by PH and that melatonin could modulate the degree of oxidative stress and through it prevent the alterations in liver function carrier.
Asunto(s)
Regeneración Hepática/efectos de los fármacos , Hígado/efectos de los fármacos , Melatonina/farmacología , Estrés Oxidativo/efectos de los fármacos , Algoritmos , Animales , Antioxidantes/farmacología , Área Bajo la Curva , Sistema Biliar/efectos de los fármacos , Sistema Biliar/metabolismo , Sistema Biliar/fisiología , Catalasa/metabolismo , Colorantes/farmacocinética , Glutatión Peroxidasa/metabolismo , Hepatectomía/métodos , Humanos , Peroxidación de Lípido/efectos de los fármacos , Hígado/fisiopatología , Hígado/cirugía , Masculino , Tasa de Depuración Metabólica , Ratas , Ratas Wistar , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Sulfobromoftaleína/farmacocinética , Factores de TiempoRESUMEN
The insults sustained by transplanted livers (hepatectomy, hypothermic preservation, and normothermic reperfusion) could compromise hepatic function. Hydrogen sulfide (H2S) is a physiologic gaseous signaling molecule, like nitric oxide (NO) and carbon monoxide (CO). We examined the effect of diallyl disulfide as a H2S donor during hypothermic preservation and reperfusion on intrahepatic resistance (IVR), lactate dehydrogenase (LDH) release, bile production, oxygen consumption, bromosulfophthalein (BSP) depuration and histology in an isolated perfused rat liver model (IPRL), after 48 h of hypothermic storage (4 °C) in University of Wisconsin solution (UW, Viaspan). Livers were retrieved from male Wistar rats. Three experimental groups were analyzed: Control group (CON): IPRL was performed after surgery; UW: IPRL was performed in livers preserved (48 h-4 °C) in UW; and UWS: IPRL was performed in livers preserved (48 h-4 °C) in UW in the presence of 3.4 mM diallyl disulfide. Hypothermic preservation injuries were manifested at reperfusion by a slight increment in IHR and LDH release compared with the control group. Also, bile production for the control group (1.32 µL/min/g of liver) seemed to be diminished after preservation by 73% in UW and 69% in UW H2S group at the end of normothermic reperfusion. Liver samples analyzed by hematoxylin/eosin clearly showed the deleterious effect of cold storage process, partially reversed (dilated sinusoids and vacuolization attenuation) by the addition of a H2S delivery compound to the preservation solution. Hepatic clearance (HC) of BSP was affected by cold storage of livers, but there were no noticeable differences between livers preserved with or without diallyl disulfide. Meanwhile, livers preserved in the presence of H2S donor showed an enhanced capacity for BSP uptake (k(A) CON = 0.29 min⻹; k(A) UW = 0.29 min⻹ ; k(A) UWS = 0.36 min ⻹). In summary, our animal model suggests that hepatic hypothermic preservation for transplantation affects liver function and hepatic depuration of BSP, and implies that the inclusion of an H2S donor during hypothermic preservation could improve standard methods of preparing livers for transplant.
Asunto(s)
Compuestos Alílicos/farmacología , Isquemia Fría , Disulfuros/farmacología , Sulfuro de Hidrógeno/metabolismo , Trasplante de Hígado , Hígado/efectos de los fármacos , Soluciones Preservantes de Órganos/farmacología , Preservación de Órganos/métodos , Daño por Reperfusión/prevención & control , Adenosina/farmacología , Alopurinol/farmacología , Compuestos Alílicos/metabolismo , Animales , Bilis/metabolismo , Isquemia Fría/efectos adversos , Disulfuros/metabolismo , Gases , Glutatión/farmacología , Glucógeno/metabolismo , Insulina/farmacología , L-Lactato Deshidrogenasa/metabolismo , Hígado/irrigación sanguínea , Hígado/metabolismo , Hígado/patología , Hígado/cirugía , Circulación Hepática , Pruebas de Función Hepática , Masculino , Preservación de Órganos/efectos adversos , Consumo de Oxígeno/efectos de los fármacos , Rafinosa/farmacología , Ratas , Ratas Wistar , Daño por Reperfusión/etiología , Daño por Reperfusión/metabolismo , Daño por Reperfusión/patología , Sulfobromoftaleína/metabolismo , Factores de Tiempo , Resistencia VascularRESUMEN
The kidneys and liver are the major routes for organic anion elimination. We have recently shown that acute obstructive jaundice is associated with increased systemic and renal elimination of two organic anions, p-aminohippurate and furosemide, principally excreted through urine. This study examined probable adaptive mechanisms involved in renal elimination of bromosulfophthalein (BSP), a prototypical organic anion principally excreted in bile, in rats with acute obstructive jaundice. Male Wistar rats underwent bile duct ligation (BDL rats). Pair-fed sham-operated rats served as controls. BSP renal clearance was performed by conventional techniques. Renal organic anion-transporting polypeptide 1 (Oatp1) expression was evaluated by immunoblotting and IHC. Excreted, filtered, and secreted loads of BSP were all higher in BDL rats compared with Sham rats. The higher BSP filtered load resulted from the increase in plasma BSP concentration in BDL rats, because glomerular filtration rate showed no difference with the Sham group. The increase in the secreted load might be explained by the higher expression of Oatp1 observed in apical membranes from kidneys of BDL animals. This likely adaptation to hepatic injury, specifically in biliary components elimination, might explain, at least in part, the huge increase in BSP renal excretion observed in this experimental model.
Asunto(s)
Colestasis Extrahepática/metabolismo , Ictericia Obstructiva/metabolismo , Riñón/metabolismo , Transportadores de Anión Orgánico Sodio-Independiente/fisiología , Sulfobromoftaleína/farmacocinética , Enfermedad Aguda , Animales , Aniones , Immunoblotting , Inmunohistoquímica , Masculino , Microvellosidades/metabolismo , Transportadores de Anión Orgánico Sodio-Independiente/biosíntesis , Ratas , Ratas WistarRESUMEN
Animal studies and premarketing clinical trials have revealed hepatotoxicity of statins, primarily minor elevations in serum alanine aminotransferase levels. The combined chronic use of medicines and eventual ethanol abuse are common and may present a synergistic action regarding liver injury. Our objective was to study the effect of the chronic use of atorvastatin associated with acute ethanol administration on the liver in a rat model. One group of rats was treated daily for 5 days a week for 2 months with 0.8 mg/kg atorvastatin by gavage. At the end of the treatment the livers were perfused with 72 mM ethanol for 60 min. Control groups (at least 4 animals in each group) consisted of a group of 2-month-old male Wistar EPM-1 rats exposed to 10% ethanol (v/v) ad libitum replacing water for 2 months, followed by perfusion of the liver with 61 nM atorvastatin for 60 min, and a group of animals without chronic ethanol treatment whose livers were perfused with atorvastatin and/or ethanol. The combination of atorvastatin with ethanol did not increase the release of injury marker enzymes (alanine aminotransferase, aspartate aminotransferase, and lactic dehydrogenase) from the liver and no change in liver function markers (bromosulfophthalein clearance, and oxygen consumption) was observed. Our results suggest that the combination of atorvastatin with ethanol is not more hepatotoxic than the separate use of each substance.
Asunto(s)
Etanol/toxicidad , Ácidos Heptanoicos/toxicidad , Hígado/efectos de los fármacos , Pirroles/toxicidad , Alanina Transaminasa/sangre , Animales , Aspartato Aminotransferasas/sangre , Atorvastatina , Biomarcadores/sangre , Sinergismo Farmacológico , Etanol/administración & dosificación , Ácidos Heptanoicos/administración & dosificación , L-Lactato Deshidrogenasa/sangre , Hígado/enzimología , Hígado/patología , Pruebas de Función Hepática , Masculino , Consumo de Oxígeno , Perfusión , Pirroles/administración & dosificación , Ratas , Ratas Wistar , Sulfobromoftaleína/farmacocinéticaRESUMEN
Animal studies and premarketing clinical trials have revealed hepatotoxicity of statins, primarily minor elevations in serum alanine aminotransferase levels. The combined chronic use of medicines and eventual ethanol abuse are common and may present a synergistic action regarding liver injury. Our objective was to study the effect of the chronic use of atorvastatin associated with acute ethanol administration on the liver in a rat model. One group of rats was treated daily for 5 days a week for 2 months with 0.8 mg/kg atorvastatin by gavage. At the end of the treatment the livers were perfused with 72 mM ethanol for 60 min. Control groups (at least 4 animals in each group) consisted of a group of 2-month-old male Wistar EPM-1 rats exposed to 10 percent ethanol (v/v) ad libitum replacing water for 2 months, followed by perfusion of the liver with 61 nM atorvastatin for 60 min, and a group of animals without chronic ethanol treatment whose livers were perfused with atorvastatin and/or ethanol. The combination of atorvastatin with ethanol did not increase the release of injury marker enzymes (alanine aminotransferase, aspartate aminotransferase, and lactic dehydrogenase) from the liver and no change in liver function markers (bromosulfophthalein clearance, and oxygen consumption) was observed. Our results suggest that the combination of atorvastatin with ethanol is not more hepatotoxic than the separate use of each substance.
Asunto(s)
Animales , Masculino , Ratas , Etanol/toxicidad , Ácidos Heptanoicos/toxicidad , Hígado/efectos de los fármacos , Pirroles/toxicidad , Alanina Transaminasa/sangre , Aspartato Aminotransferasas/sangre , Biomarcadores/sangre , Sinergismo Farmacológico , Etanol/administración & dosificación , Ácidos Heptanoicos/administración & dosificación , L-Lactato Deshidrogenasa/sangre , Pruebas de Función Hepática , Hígado/enzimología , Hígado/patología , Consumo de Oxígeno , Perfusión , Pirroles/administración & dosificación , Ratas Wistar , Sulfobromoftaleína/farmacocinéticaRESUMEN
The effects of a chronic aluminum (Al) exposure on biliary secretory function, with special emphasis on hepatic handling of non-bile salt organic anions, was investigated. Male Wistar rats received, intraperitoneally, either 27 mg/kg body weight of Al, as Al hydroxide [Al (+) rats], or the vehicle saline [Al (-) rats] three times a week for 3 months. Serum and hepatic Al levels were increased by the treatment (approximately 9- and 4-fold, respectively). This was associated with enhanced malondialdehyde formation (+110%) and a reduction in GSH content (-17%) and in the activity of the antioxidant enzymes catalase (-84%) and GSH peroxidase (-46%). Bile flow (-23%) and the biliary output of bile salts (-39%), cholesterol (-43%), and proteins (-38%) also decreased. Compartmental analysis of the plasma decay of the model organic anion bromosulphophthalein revealed that sinusoidal uptake and canalicular excretion of the dye were significantly decreased in Al (+) rats (-53 and -43%, respectively). Expression of multidrug resistance-associated protein 2 (Mrp2), the main, multispecific transporter involved in the canalicular excretion of organic anions, was also decreased (-40%), which was associated with a significant decrease in the cumulative biliary excretion of the Mrp2 substrate, dinitrophenyl-S-glutathione (-50%). These results show that chronic Al exposure leads to oxidative stress, cholestasis, and impairment of the hepatic handling of organic anions by decreasing both sinusoidal uptake and canalicular excretion. The alteration of the latter process seems to be causally related to impairment of Mrp2 expression. We have addressed some possible mechanisms involved in these deleterious effects.
Asunto(s)
Aluminio/envenenamiento , Canalículos Biliares/efectos de los fármacos , Canalículos Biliares/metabolismo , Bilis/metabolismo , Glutatión/análogos & derivados , Hidróxido de Aluminio/administración & dosificación , Hidróxido de Aluminio/sangre , Hidróxido de Aluminio/envenenamiento , Animales , Bilis/efectos de los fármacos , Ácidos y Sales Biliares/antagonistas & inhibidores , Ácidos y Sales Biliares/metabolismo , Catalasa/antagonistas & inhibidores , Catalasa/metabolismo , Colestasis/inducido químicamente , Colesterol/metabolismo , Enfermedad Crónica , Esquema de Medicación , Evaluación Preclínica de Medicamentos/métodos , Expresión Génica , Glutatión/antagonistas & inhibidores , Glutatión/química , Glutatión/efectos de los fármacos , Glutatión/metabolismo , Glutatión Peroxidasa/antagonistas & inhibidores , Glutatión Peroxidasa/metabolismo , Glutatión Transferasa/química , Glutatión Transferasa/metabolismo , Inyecciones Intraperitoneales , Hígado/química , Hígado/efectos de los fármacos , Masculino , Proteínas Mitocondriales/antagonistas & inhibidores , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Estrés Oxidativo/efectos de los fármacos , Proteínas/antagonistas & inhibidores , Proteínas/metabolismo , Ratas , Ratas Wistar , Proteínas Ribosómicas/antagonistas & inhibidores , Proteínas Ribosómicas/genética , Proteínas Ribosómicas/metabolismo , Proteínas de Saccharomyces cerevisiae/antagonistas & inhibidores , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Sulfobromoftaleína/metabolismo , Sulfobromoftaleína/farmacocinética , Sustancias Reactivas al Ácido Tiobarbitúrico/química , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismoRESUMEN
BSP/Bilirubin binding protein (BBBP) is a protein located on the sinusoidal membrane of the liver that transport several organic anions. The aim of this investigation was to determine whether BBBP is present in the kidney and its role in p-aminohippurate transport (PAH). Anti-BBBP antibodies inhibited PAH uptake in brush border membrane vesicles (BBMV) and Na(+)-independent PAH uptake in basolateral membrane vesicles (BLMV). Western blot studies revealed positivity to antiBBBP antibodies in both BBMV and BLMV. So BBBP is also expressed in the kidneys and accounts, at least in part, for the renal tubular transport of PAH.
Asunto(s)
Proteínas Portadoras/metabolismo , Riñón/metabolismo , Sulfobromoftaleína/metabolismo , Ácido p-Aminohipúrico/metabolismo , Animales , Anticuerpos/farmacología , Transporte Biológico/efectos de los fármacos , Femenino , Cinética , Masculino , Microvellosidades/metabolismo , Ratas , Ratas WistarRESUMEN
The action of extracellular ATP on organic anion transport in the bivascularly perfused rat liver was investigated, using bromosulfophthalein as a model substance. Transport was measured by means of the multiple-indicator dilution technique. The action of portal 100 microM ATP presented the following characteristics: (a) inhibition of bromosulfophthalein single pass extraction; the inhibition degree decreased with increasing bromosulfophthalein doses; (b) diminution of the influx rate coefficients; (c) 86.7% decrease of the maximal activity of the saturable component for bromosulfophthalein transport, but 100% increase of the non-saturable component; (d) diminution of the bromosulfophthalein flow-limited distribution space; (e) no significant alteration of the rate coefficients for metabolic sequestration. The action of ATP on organic anion transport in the intact liver occurred at much lower concentrations (10x) than those previously reported for isolated hepatocytes. This reinforces the suggestion that inhibition of organic anion transport could be a physiologically relevant effect of extracellular ATP.
Asunto(s)
Adenosina Trifosfato/farmacología , Espacio Extracelular/efectos de los fármacos , Hígado/efectos de los fármacos , Sulfobromoftaleína/metabolismo , Animales , Transporte Biológico/efectos de los fármacos , Transporte Biológico/fisiología , Relación Dosis-Respuesta a Droga , Espacio Extracelular/metabolismo , Hígado/metabolismo , Masculino , Transportadores de Anión Orgánico ATP-Dependiente/antagonistas & inhibidores , Transportadores de Anión Orgánico ATP-Dependiente/metabolismo , Perfusión/métodos , Ratas , Ratas WistarRESUMEN
Adaptive hepatic changes were investigated in rats with mild stenosis of the common bile duct and in sham-operated controls. The studies were performed 24 h and 7-12 days postoperatively. A continuous intravenous infusion of taurocholic acid at stepwise-increasing rates was performed to explore the responses to bile acid effects. During the infusion, bile flow and the outputs of bile acids, phospholipids, cholesterol, alkaline phosphatase and gamma glutamyl transpeptidase were studied. At the end of the infusion, hepatic morphometric measurements were performed. In other experimental sets, biliary excretions of horseradish peroxidase, a marker of microtubule-dependent vesicular transport in the hepatocyte, and sulphobromophthalein, a well-known organic anion model, were studied. In other rats, bile acid pool size and composition were determined by depletion of bile. The results in rats with mild stenosis maintained for 24 h showed a greater susceptibility to the toxicity of taurocholic acid, as revealed by the abrupt decrement in bile flow at high rates of infusion, and increased outputs of phospholipids and canalicular enzymes. Conversely, rats with mild stenosis maintained for 7-12 days showed decreased bile acid maximum secretory rate and biliary outputs of phospholipids and canalicular enzymes, as well as hepatocyte hypertrophy. These findings may explain the limited hepatic and systemic repercussion of experimental mild stenosis of the common bile duct and help us to understand the early stages of constriction of the common bile duct in man.
Asunto(s)
Adaptación Fisiológica/fisiología , Colestasis Extrahepática/patología , Enfermedades del Conducto Colédoco/patología , Hígado/enzimología , Fosfatasa Alcalina/metabolismo , Animales , Ácidos y Sales Biliares/análisis , Ácidos y Sales Biliares/metabolismo , Colestasis Extrahepática/metabolismo , Enfermedades del Conducto Colédoco/metabolismo , Constricción Patológica , Peroxidasa de Rábano Silvestre/farmacocinética , Concentración de Iones de Hidrógeno , Inyecciones Intravenosas , Hígado/efectos de los fármacos , Masculino , Ratas , Ratas Wistar , Sulfobromoftaleína/farmacocinética , Ácido Taurocólico/farmacología , gamma-Glutamiltransferasa/metabolismoRESUMEN
The hepatic uptake of the bilirubin-bilirubin-sulfobromophthalein (BSP) group of organic anions is a carrier-mediated process and is accounted for by at least four distinct plasma membrane proteins (bilitranslocase, BSP/bilirubin-binding protein, organic anion-binding protein and the organic anion transport protein). In order to investigate the regulation of basolateral organic anion uptake, BSP transport was measured in rat basolateral liver plasma membrane vesicles in the presence of ATP. ATP significantly stimulated the electroneutral uptake of BSP with an increment in Vmax compared with control (1.57 +/- 0.14 vs 0.73 +/- 0.06 nmol BSP/mg protein per 15 s, respectively; P < 0.001) while the apparent K(m) was not changed significantly (12 +/- 1 vs 12 +/- 2 mumol/L). The stimulatory effect was dose-dependent for ATP (K(m) 1.01 +/- 0.37 mmol/L). ATP had no detectable effect on the electrogenic component of BSP transport. Other nucleotides (ADP, AMP, GTP) and non-hydrolysable ATP did not enhance BSP uptake, suggesting that ATP hydrolysis was necessary for the effect. This was supported by the lack of effect on BSP uptake when ATP was added in the presence of vanadate. The addition of phorbol-12-myristate 13-acetate, an activator of protein kinase C (PKC), increased BSP uptake in a dose-dependent manner in the presence, but not in the absence, of ATP. Incubation of vesicles with staurosporine, an inhibitor of PKC activity, resulted in a dose-dependent inhibition of ATP-sensitive BSP transport. These data indicate that electroneutral BSP hepatic uptake is modulated by ATP. The effect is related to ATP hydrolysis and involves the activity of PKC.
Asunto(s)
Adenosina Trifosfato/fisiología , Hígado/metabolismo , Sulfobromoftaleína/metabolismo , Animales , Transporte Biológico/efectos de los fármacos , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Relación Dosis-Respuesta a Droga , Femenino , Hígado/ultraestructura , Ratas , Ratas Wistar , Estaurosporina/farmacología , Acetato de Tetradecanoilforbol/farmacología , Factores de Tiempo , Vanadatos/farmacologíaRESUMEN
Changes in hepatic paracellular permeability were investigated during the development of cholephilic dye-induced cholestasis in rats. For this purpose, four dyes with different cholestatic potency (phenol red, sulfobromophthalein, bromcresol green and rose bengal) were infused at a high, potentially damaging dose (280 nmol/min per 100 g body wt., i.v.), and changes in paracellular permeability were continuously monitored by measuring the access into bile of the permeability probe -14C-sucrose. The cholestatic potency of the different dyes was: rose bengal > bromcresol green > sulfobromophthalein > phenol red. All dyes increased [14C]sucrose bile-to-plasma ratio, producing a displacement towards curves of higher permeability. The capability of the dyes to increase biliary permeability followed the same order as their respective cholestatic potencies. The possible implications of the present results for cholephilic dye-induced cholestasis are discussed.
Asunto(s)
Sistema Biliar/efectos de los fármacos , Permeabilidad de la Membrana Celular/efectos de los fármacos , Colestasis/inducido químicamente , Colorantes/toxicidad , Animales , Bilis/química , Bilis/fisiología , Sistema Biliar/metabolismo , Verde de Bromocresol/administración & dosificación , Verde de Bromocresol/análisis , Verde de Bromocresol/toxicidad , Colestasis/metabolismo , Colorantes/administración & dosificación , Inyecciones Intravenosas , Uniones Intercelulares/metabolismo , Pruebas de Función Hepática , Masculino , Fenolsulfonftaleína/administración & dosificación , Fenolsulfonftaleína/análisis , Fenolsulfonftaleína/toxicidad , Ratas , Ratas Wistar , Rosa Bengala/administración & dosificación , Rosa Bengala/análisis , Rosa Bengala/toxicidad , Sacarosa/metabolismo , Sulfobromoftaleína/administración & dosificación , Sulfobromoftaleína/análisis , Sulfobromoftaleína/toxicidad , Factores de TiempoRESUMEN
Several techniques for developing incomplete obstruction of the common bile duct have been described but none of them properly represents a compression or constriction of the bile duct. In this study, a mild stenosis of the common bile duct was achieved in the rat by means of a double ligature including a cannula that could be easily slipped out of the ligatures. Sham-operated rats were used as controls. The studies, performed 7-10 days postoperatively, indicated that in ligated rats a duct constriction was produced, made evident by an increase of the biliary pressure, an upstream dilatation of the bile duct, an increase of the liver volume constituted by portal tracts, and ductular proliferation. Serum parameters were practically similar in ligated and control rats, except for a slight increase in serum bilirubin. Following intravenous injection of sodium taurocholate there were rapid increases of bile flow and bile salt output in both groups, but choleresis induced by sodium taurocholate was higher in ligated rats than in controls. The clearances of [14C]erythritol and [14C]sucrose suggested that ductular water contributing to bile flow and changes in biliary permeability were not involved in ligated rats. The limited repercussion of humoral effects and hepatic behaviour seen in ligated rats despite the morphological alterations induced make the mild stenosis of the bile duct a good model for the study of early stages of compression or constriction of the biliary tract.
Asunto(s)
Enfermedades del Conducto Colédoco/etiología , Animales , Bilis/fisiología , Ácidos y Sales Biliares/metabolismo , Bilirrubina/sangre , Colagogos y Coleréticos/farmacología , Enfermedades del Conducto Colédoco/patología , Enfermedades del Conducto Colédoco/fisiopatología , Constricción Patológica , Modelos Animales de Enfermedad , Ligadura , Masculino , Presión , Ratas , Ratas Wistar , Sulfobromoftaleína/farmacología , Ácido Taurocólico/farmacología , Factores de TiempoRESUMEN
Changes in biliary permeability during cholephilic dye-induced choleresis, as assessed by measuring the movement into bile of two permeability probes, [14C]sucrose and horseradish peroxidase, were analyzed following an i.v. infusion (60 nmol/min per 100 g body wt) of the model cholephilic organic anion sulfobromophthalein in rats. Dye infusion led to a progressive increase of the [14C]sucrose bile-to-plasma ratio, which reached a maximum value after 100 min of dye infusion (+97%). Paracellular entry of horseradish peroxidase, as evaluated by the early peak of its biliary appearance curve, was also selectively increased (+69%), without changes in the later (transcytotic) access of the protein. Additional dose-response studies of biliary permeability to [14C]sucrose, using sulfobromophthalein and rose bengal, showed that this effect was dose-dependent and rapidly reversed by interruption of dye administration. The influence of hydrophobic/hydrophilic balance on this effect was also studied by infusing four dyes covering a broad range of hydrophobicity (phenol red, bromocresol green, sulfobromophthalein, and rose bengal), so as to attain a similar value of dye hepatic content at the end of the experiment (approximately 150 nmol/g liver wt). Under these conditions, a strong positive correlation was found between the increase in biliary permeability to [14C]sucrose and dye hydrophobicity. These results suggest that cholephilic dyes increase tight junctional permeability in a reversible and dose-dependent manner, and that this effect depends on the hydrophobic/hydrophilic balance of the dye.
Asunto(s)
Colorantes/farmacología , Conducto Colédoco/efectos de los fármacos , Hígado/efectos de los fármacos , Sulfobromoftaleína/farmacología , Uniones Estrechas/efectos de los fármacos , Animales , Bilis/metabolismo , Conducto Colédoco/metabolismo , Peroxidasa de Rábano Silvestre/metabolismo , Infusiones Intravenosas , Hígado/metabolismo , Masculino , Permeabilidad/efectos de los fármacos , Ratas , Ratas Wistar , Sacarosa/metabolismoRESUMEN
The hepatic transport of organic anions was evaluated in taurolithocholate-induced cholestasis in rats. Taurolithocholate (3 mumol per 100 g body wt., i.v.) diminished bile flow by 61%, whereas biliary excretion of bile salts was normalized after 80 min. Tm studies of sulfobromophthalein revealed reduced biliary excretion (-58%) and increased hepatic content of the dye (+75%). Conjugation pattern in bile showed that free sulfobromophthalein was increased by 57%, suggesting that hepatic conjugation was also impaired. This finding, however, could not fully explain the reduced sulfobromophthalein excretion since Tm of its non-metabolizable analog phenol-3,6-dibromophthalein was also decreased (-41%). Compartmental analysis of plasma decay of both dyes revealed that, whereas hepatic uptake was unaltered, canalicular excretion was reduced and reflux from the liver into plasma was increased by the cholestatic agent. Studies on transport of phenol-3,6-dibromophthalein by isolated hepatocytes showed that while uptake was unaffected, the treatment reduced (-36%) the release from hepatocytes preloaded with the dye. Neither glutathione S-transferase activity nor binding of sulfobromophthalein to cytosolic proteins was altered when evaluated in vitro, suggesting that reduced conjugation and enhanced sinusoidal reflux were not due to an irreversible effect of taurolithocholate on this enzyme. In conclusion, taurolithocholate impairs the hepatic transport of organic anions by impairing canalicular excretion and intrahepatic conjugation, as well as by increasing transfer from the liver into the plasma.
Asunto(s)
Aniones/farmacocinética , Colestasis/inducido químicamente , Colestasis/metabolismo , Hígado/metabolismo , Ácido Taurolitocólico , Animales , Bilis/metabolismo , Transporte Biológico , Citosol/metabolismo , Hígado/citología , Masculino , Proteínas/metabolismo , Ratas , Ratas Wistar , Sulfobromoftaleína/análogos & derivados , Sulfobromoftaleína/farmacocinéticaRESUMEN
Com o objetivo de contribuir para o esclarecimento das relaçöes entre o efeito dos venenos botrópico e crotálico e do soro antiofídico, na gênese das alteraçöes hepáticas em doentes picados por serpentes dos gêneros Bothrops e Crotalus, avaliaram-se as funçöes hematológica, bioquímica, renal e hepática de ratos Wistar inoculados com soro anticrotálico e veneno total de Crotalus durissus terrificus, por meio de dosagens enzimáticas e análise ultra-estrutural do fígado. A análise dos resultados permitiu as seguintes conclusöes: - Os níveis da velocidade de hemossedimentaçäo foram menores e os valores do tempo de coagulaçäo foram maiores nos doentes do grupo Crotalus. Estas alteraçöes foram mais pronunciadas neste grupo de doentes, em decorrência do atendimento médico tardio. - Os níveis de glóbulos brancos, bastonetes e segmentados foram elevados nos grupos Bothrops e Crotalus, os níveis de leucócitos e eosinófilos foram menores nos doentes do grupo Crotalus. Possivelmente, estas alteraçöes ocorreram devido a liberaçäo de linfocinas pelas células alvo do organismo acidentado. Estas atuariam na medula óssea, liberando células jovens, no hipotálamo, liberando o hormônio adreno-corticotrófico e, como consequência, aumentando a liberaçäo de cortisol pela glândula supra-renal, causando depressäo da resposta imune celular. - Os níveis de bilirrubina indireta, aspartato aminotransferase, creatinina quinase e desidrogenase lática foram maiores no primeiro dia de internaçäo, tanto nos doentes do grupo Bothrops quanto do Crotalus. Estas alteraçöes foram mais pronunciadas nos doentes do grupo Crotalus e deveram-se à açäo miotóxica do veneno. - Os níveis séricos das mucoproteínas e da proteína C reativa estiveram aumentados no primeiro dia de internaçäo tanto nos doentes do grupo Bothrops, quanto de Crotalus. Os níveis séricos de proteínas totais e fraçöes e albumina foram menores no primeiro dia de internaçäo, tanto nos doentes do grupo Bothrops, quanto Crotalus. Estas alteraçöes deveram-se ao trauma agudo grave sofrido pelos doentes em decorrência do envenenamento ofídico. Neste caso, houve provavelmente liberaçäo de linfocinas (interleucina 1, 6 e fator necrosante de tumor) que atuaram no fígado aumentando a produçäo das proteínas positivas e diminuindo as negativas da fase aguda. Cinquenta e três por cento dos doentes do grupo Crotalus, com ausência de antecedentes de ingestäo de álcool e anticorpos anti-HBsAg negativos apresentaram aumento da retençäo...
Asunto(s)
Animales , Humanos , Preescolar , Niño , Adolescente , Adulto , Persona de Mediana Edad , Femenino , Masculino , Ratas , Bothrops , Crotalus , Hepatopatías , Venenos de Crotálidos/envenenamiento , Antivenenos/uso terapéutico , Hígado/fisiopatología , Hígado/ultraestructura , Hepatopatías/etiología , Ratas Wistar , Mordeduras de Serpientes , SulfobromoftaleínaAsunto(s)
Animales , Conejos , Prajmalina/toxicidad , Sulfobromoftaleína/farmacocinética , SulfobromoftaleínaRESUMEN
Escasas publicaciones abordan el efecto del primer paso de la prajmalina (N-propil ajmalina bitartrato), por lo que surgieron interrogantes sobre una posible respuesta hepatotóxica. Mediante valoraciones farmacocinéticas modelo dependiente en las que se emplean bromosulftaleína (BSP) como una medida de la función excretora del hígado, se demuestra que la prajmalina en aplicación crónica, prvoca efectos hepatotóxicos sobre un modelo experimental animal. Los valores obtenidos de la constante de depuración (K) se correlacionan con otras mediciones realizadas por el mismo colectivo de otros trabajos: variación de la fracción albúmina índices transaminasa glutamicooxalacética/fosfolipasa A2 (GOT/FPA) y creatin-fosfoquinasa/fosfolipasa A2 (CPK/FPA); se definen períodos críticos de degeneración de la capacidad excretora
Asunto(s)
Conejos , Animales , Prajmalina/toxicidad , Sulfobromoftaleína , Sulfobromoftaleína/farmacocinéticaRESUMEN
Escasas publicaciones abordan el efecto del primer paso de la prajmalina (N-propil ajmalina bitartrato), por lo que surgieron interrogantes sobre una posible respuesta hepatotóxica. Mediante valoraciones farmacocinéticas modelo dependiente en las que se emplean bromosulftaleína (BSP) como una medida de la función excretora del hígado, se demuestra que la prajmalina en aplicación crónica, prvoca efectos hepatotóxicos sobre un modelo experimental animal. Los valores obtenidos de la constante de depuración (K) se correlacionan con otras mediciones realizadas por el mismo colectivo de otros trabajos: variación de la fracción albúmina índices transaminasa glutamicooxalacética/fosfolipasa A2 (GOT/FPA) y creatin-fosfoquinasa/fosfolipasa A2 (CPK/FPA); se definen períodos críticos de degeneración de la capacidad excretora
Asunto(s)
Conejos , Animales , Prajmalina/toxicidad , Sulfobromoftaleína , Sulfobromoftaleína/farmacocinéticaRESUMEN
Cytosol obtained from bovine intestinal mucosa, contains two protein fractions that bind sulfobromophthalein and are able to remove [1-14C] palmitic acid from microsomal membranes. The high molecular weight protein fraction (F1) increases the binding of sulfobromophthalein 2 and 8 times respectively after heating at 60 degrees C during 5 min or delipidation. These changes do not correlate with the rate of palmitic acid removal from microsomes. F1 native or delipidated is more efficient than the low molecular weight protein (F2) on the removal of [1-14C]palmitic acid from microsomes. Two protein fractions DE-I and DE-II obtained from F1 by DEAE-cellulose chromatography have palmitic acid- and sulfobromophthalein-binding capacities respectively.