RESUMO
Uranium salts, such as uranyl nitrate, induce severe renal dysfunction and tubular necrosis and a significant impairment of both oxygen dependent erythropoietin production and response to recombinant human erythropoietin. All effects are transient and reach maximal severity on the 7th day post injection. We investigated the effects of ethane 1-hydroxy-1, 1-bisphosphonate, which counteracts the inhibitory effect of uranyl nitrate on bone formation, on the negative erythropoietic effects of uranyl nitrate. Adult female Wistar rats received 1 mg/kg body weight of uranyl acetate by the i.v. route. Ethane 1-hydroxy-1,1-bisphosphonate was injected simultaneously at a dose of 7.5 mg/kg by the same route. Seven days after drug injections, plasma erythropoietin was estimated after hypobaric hypoxemia or cobalt chloride administration. The response to exogenous erythropoietin was also measured in uranyl nitrate- and/or ethane 1-hydroxy-1,1-bisphosphonate-injected rats made polycythemic by transfusion. The erythroid response was quantitated in terms of red blood cell 59iron uptake. Ethane 1-hydroxy-1, 1-bisphosphonate counteracted the effect of uranyl nitrate on oxygen-dependent and cobalt-dependent erythropoietin production, but did not correct the right shift of the dose-response relationship for exogenous erythropoietin induced by uranyl nitrate in the polycythemic rat.
Assuntos
Eritropoese/efeitos dos fármacos , Ácido Etidrônico/farmacologia , Nitrato de Uranil/toxicidade , Animais , Interações Medicamentosas , Eritropoetina/administração & dosagem , Eritropoetina/biossíntese , Eritropoetina/farmacologia , Ácido Etidrônico/administração & dosagem , Feminino , Humanos , Rim/efeitos dos fármacos , Rim/fisiologia , Ratos , Ratos Wistar , Proteínas Recombinantes , Nitrato de Uranil/administração & dosagem , Nitrato de Uranil/antagonistas & inibidoresRESUMO
Female Wistar rats were placed for 3 weeks in a simulated chamber evacuated by a vacuum pump and maintained at 40.5 kPa (7100 m). Dose-response curves were obtained through the sequential injection, via the femoral vein, of increasing doses of methacholine, methoxamine, isoprenaline and substance P. The secretory activity in the parotid gland after exposure to chronic hypoxia was significantly decreased for all agonists studied, and the submaxillary gland showed the same behaviour except in relation to isoprenaline, which did not show a significant difference compared to controls. These data suggest that changes in the number or sensitivity of autonomic receptors and/or alterations in the intracellular signals caused by hypoxia may be involved in the reduction in salivary secretory responses.
Assuntos
Hipóxia/complicações , Saliva/metabolismo , Glândulas Salivares/metabolismo , Xerostomia/etiologia , Animais , Barotrauma/complicações , Doença Crônica , Feminino , Isoproterenol/farmacologia , Cloreto de Metacolina/farmacologia , Metoxamina/farmacologia , Glândula Parótida/metabolismo , Ratos , Ratos Wistar , Glândulas Salivares/efeitos dos fármacos , Taxa Secretória , Estimulação Química , Glândula Submandibular/metabolismo , Substância P/farmacologiaAssuntos
Eritropoetina/biossíntese , Hipóxia/metabolismo , Túbulos Renais Proximais/patologia , Animais , Eritropoetina/antagonistas & inibidores , Eritropoetina/sangue , Feminino , Hipóxia/induzido quimicamente , Hipóxia/patologia , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/fisiopatologia , Cloreto de Mercúrio/toxicidade , Necrose , Dicromato de Potássio/toxicidade , Ratos , Ratos Wistar , Valores de Referência , UrinaRESUMO
The effects of acute renal failure on the impeded (IER) and unimpeded (UER) eruption dental rate and attrition rate (AR) were investigated. Adult female Wistar rats were injected with 125 mg/kg b.w of human methemoglobin (M-Hb) in order to induce a first episode of hemodynamically-mediated acute renal failure (H-ARF). Ten days after the injection of M-Hb, other groups of rats received another equal dose of the drug in order to induce a second episode of H-ARF. A group of six animals was pair-fed daily and individually with rats of M-Hb groups. Evaluation of renal function, histopathology studies, IER, UER, food intake (FI), AR and body weight gains was performed at different times after the first and second injections, of M-Hb. Treatment induced transient increases in plasma urea concentration and urine volume, and significant depression in urine osmolality, body weight gains, IER, UER and AR. In every case, the maximal effect of the first injection of M-Hb on the individual parameters was always greater than that of the second injection. Histologic sections showed interstitial cellular infiltration, desquamation of the proximal tubular epithelium and collapse or dilation of the tubular lumen. The functional values of kidney, histologic findings, IER, UER and AR of the pair-fed rats were not significantly different from control values. The results of the present study indicate that dental eruption rate (IER and UER) is relatively low in uremic rats with kidney tubule lesions and that both parameters are related.
Assuntos
Injúria Renal Aguda/fisiopatologia , Erupção Dentária , Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/complicações , Análise de Variância , Animais , Feminino , Metemoglobina , Ratos , Ratos Wistar , Estatísticas não Paramétricas , Atrito Dentário/etiologiaRESUMO
The effects of acute renal failure on the impeded (IER) and unimpeded (UER) eruption dental rate and attrition rate (AR) were investigated. Adult female Wistar rats were injected with 125 mg/kg b.w of human methemoglobin (M-Hb) in order to induce a first episode of hemodynamically-mediated acute renal failure (H-ARF). Ten days after the injection of M-Hb, other groups of rats received another equal dose of the drug in order to induce a second episode of H-ARF. A group of six animals was pair-fed daily and individually with rats of M-Hb groups. Evaluation of renal function, histopathology studies, IER, UER, food intake (FI), AR and body weight gains was performed at different times after the first and second injections, of M-Hb. Treatment induced transient increases in plasma urea concentration and urine volume, and significant depression in urine osmolality, body weight gains, IER, UER and AR. In every case, the maximal effect of the first injection of M-Hb on the individual parameters was always greater than that of the second injection. Histologic sections showed interstitial cellular infiltration, desquamation of the proximal tubular epithelium and collapse or dilation of the tubular lumen. The functional values of kidney, histologic findings, IER, UER and AR of the pair-fed rats were not significantly different from control values. The results of the present study indicate that dental eruption rate (IER and UER) is relatively low in uremic rats with kidney tubule lesions and that both parameters are related.
RESUMO
The effects of acute renal failure on the impeded (IER) and unimpeded (UER) eruption dental rate and attrition rate (AR) were investigated. Adult female Wistar rats were injected with 125 mg/kg b.w of human methemoglobin (M-Hb) in order to induce a first episode of hemodynamically-mediated acute renal failure (H-ARF). Ten days after the injection of M-Hb, other groups of rats received another equal dose of the drug in order to induce a second episode of H-ARF. A group of six animals was pair-fed daily and individually with rats of M-Hb groups. Evaluation of renal function, histopathology studies, IER, UER, food intake (FI), AR and body weight gains was performed at different times after the first and second injections, of M-Hb. Treatment induced transient increases in plasma urea concentration and urine volume, and significant depression in urine osmolality, body weight gains, IER, UER and AR. In every case, the maximal effect of the first injection of M-Hb on the individual parameters was always greater than that of the second injection. Histologic sections showed interstitial cellular infiltration, desquamation of the proximal tubular epithelium and collapse or dilation of the tubular lumen. The functional values of kidney, histologic findings, IER, UER and AR of the pair-fed rats were not significantly different from control values. The results of the present study indicate that dental eruption rate (IER and UER) is relatively low in uremic rats with kidney tubule lesions and that both parameters are related.
RESUMO
A study of the effect of acute renal failure (ARF) on the growth of the skeletal units of the mandible was performed. Male Wistar rats weighing 35-40 g were assigned to three groups. One of the groups received a basal choline-deficient diet ad libitum. A second group was pair-fed with the first one and was given a basal diet supplemented with 0.35 g choline chloride/100 g of diet. The third group was fed a basal diet plus 0.35 g choline chloride/100 g of diet ad libitum and used as the normal control. Body length, renal function parameters and measurements of the mandible were recorded at the end of a 12-day period on the different diets. Food intake and body weight were recorded every day. Plasma urea and creatinine concentrations markedly increased over the first 12 days of exposure to a choline-deficient diet. Significant increases in urine volume and significant depressions in urine osmolality were also observed. The average body weight and body length gains for rats given the choline-deficient diet were lower than those of control rats. There were no significant differences between the average body weight and body length of pair-fed and normal rats. All skeletal measurements of the mandible of the choline-deficient group differed significantly from those of the control group. These differences varied between 7% and 30%. The skeletal units of the mandible of the pair-fed group did not differ significantly from ad libitum controls. This study suggests that this rat model can be used for the investigation of the different alterations observed in uremia.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Injúria Renal Aguda/fisiopatologia , Mandíbula/crescimento & desenvolvimento , Injúria Renal Aguda/sangue , Injúria Renal Aguda/urina , Processo Alveolar/crescimento & desenvolvimento , Processo Alveolar/patologia , Animais , Estatura , Peso Corporal , Creatinina/sangue , Ingestão de Alimentos , Masculino , Mandíbula/patologia , Côndilo Mandibular/crescimento & desenvolvimento , Côndilo Mandibular/patologia , Concentração Osmolar , Ratos , Ratos Endogâmicos , Ureia/sangue , Uremia/sangue , Uremia/fisiopatologia , Uremia/urinaRESUMO
Adult female Wistar rats were injected with 125 mg/kg b.w. of human methemoglobin (M-Hb) in order to induce a first episode of hemodynamically-mediated acute renal failure (HMARF). Eleven days after the injection of M-Hb, other groups of rats received another equal dose of the drug in order to induce a second episode of HMARF. Evaluation of renal function, histopathology studies, and determinations of plasma and kidney erythropoietin (Epo) titers by radioimmunoassay in normoxic and hypoxic conditions were performed 1, 2, 3, 5 and 10 days after M-Hb administration. Treatment induced transient increases in plasma urea concentration, fractional sodium excretion, and urine volume, and significant depression in urine osmolality. In every case, the maximal effect of the first injection of M-Hb on the individual parameters was always greater than that of the second injection, and observed on the 5th post-injection day. Histologic sections showed interstitial cellular infiltration, desquamation of the proximal tubular epithelium and collapse or dilation of the tubular lumen. Treatment with M-Hb depressed Epo titers in both kidney homogenates and plasma in normoxic as well as hypoxic rats. Here again, the effect of the first injection of the drug was higher than that of the second one. These observations indicate that there is a negative correlation between kidney tubule injury and Epo production in normoxic and hypoxic conditions. The findings give support to the concept that Epo production is related to proximal tubular function.
Assuntos
Injúria Renal Aguda/sangue , Eritropoetina/sangue , Injúria Renal Aguda/induzido quimicamente , Análise de Variância , Animais , Peso Corporal/efeitos dos fármacos , Eritropoetina/biossíntese , Feminino , Túbulos Renais/efeitos dos fármacos , Metemoglobina , Tamanho do Órgão/efeitos dos fármacos , Oxigênio/metabolismo , Ratos , Ratos EndogâmicosRESUMO
Adult female Wistar rats were injected with 125 mg/kg b.w. of human methemoglobin (M-Hb) in order to induce a first episode of hemodynamically-mediated acute renal failure (HMARF). Eleven days after the injection of M-Hb, other groups of rats received another equal dose of the drug in order to induce a second episode of HMARF. Evaluation of renal function, histopathology studies, and determinations of plasma and kidney erythropoietin (Epo) titers by radioimmunoassay in normoxic and hypoxic conditions were performed 1, 2, 3, 5 and 10 days after M-Hb administration. Treatment induced transient increases in plasma urea concentration, fractional sodium excretion, and urine volume, and significant depression in urine osmolality. In every case, the maximal effect of the first injection of M-Hb on the individual parameters was always greater than that of the second injection, and observed on the 5th post-injection day. Histologic sections showed interstitial cellular infiltration, desquamation of the proximal tubular epithelium and collapse or dilation of the tubular lumen. Treatment with M-Hb depressed Epo titers in both kidney homogenates and plasma in normoxic as well as hypoxic rats. Here again, the effect of the first injection of the drug was higher than that of the second one. These observations indicate that there is a negative correlation between kidney tubule injury and Epo production in normoxic and hypoxic conditions. The findings give support to the concept that Epo production is related to proximal tubular function.