RESUMO
The aim of this study was to evaluate renal damage in animals treated with lithium continuously versus intermittently. Rats were randomized into three groups: control group fed ad libitum powered standard diet for 3 months and two experimental groups, one of them fed ad libitum the same diet or the same diet supplemented with 60 mmol of lithium/kg diet every alternate week, for 3 months and the other fed ad libitum powered standard diet for one and a half month and the same diet supplemented with 60 mmol of lithium/kg diet for the last month and a half. Lithemias in experimental groups were within therapeutic range used in humans. At the end of the protocol, diuresis was higher in experimental groups compared to control group. There was no difference in serum creatinine and creatinine clearance. Both experimental groups showed hypertrophy, hyperplasia, and dilatation of cortical collecting tubules although dilatation was greater in continuous group. Longer studies are necessary to clarify the evolution of renal damage. Our preliminary study shows that histopathological damage associated with the use of lithium occurs during both continuous and intermittent treatment, but it seems to be somewhat greater in the continuous group.
Assuntos
Rim , Lítio , Animais , Creatinina , Dieta , Lítio/toxicidade , RatosRESUMO
OBJECTIVES: The aim of the present study was to assess whether there is a relationship between serum lithium concentrations and the magnitude of kidney damage in a preclinical model. METHODS: Thirty Wistar male rats were randomized into three groups: control group fed ad libitum powered standard diet for 3 months; and experimental groups fed ad libitum the same diet supplemented with 30 or 60 mmol/kg diet for 3 months (LowLi and HighLi groups respectively). Laboratory parameters were assessed at months 1 and 3 and histopathological changes were evaluated after 3 months. RESULTS: Serum lithium levels in experimental rats were within therapeutic range used in humans throughout the entire experiment. After 3 months of treatment, lithium levels were statistically higher in HighLi group. Rats of the LowLi group showed dilation of cortical tubules although with similar clearance of creatinine. Rats from the HighLi group had greater histopathological damage in addition to lower creatinine clearance than the other two groups. CONCLUSIONS: Our study suggests that during long-term treatments, even with serum lithium levels within the therapeutic range used in humans, the risk of kidney damage could increase proportionally to the serum lithium concentration.
Assuntos
Nefropatias/sangue , Lítio/sangue , Animais , Transtorno Bipolar/tratamento farmacológico , Creatinina/sangue , Creatinina/urina , Humanos , Nefropatias/urina , Masculino , Distribuição Aleatória , Ratos , Ratos WistarRESUMO
Long-term lithium treatment was associated with chronic kidney disease and renal failure although the underlying pathogenic mechanisms are not certainty known. The aim of this study was to evaluate changes in oxidative stress measures as well as renal functional and structural alterations associated with chronic use of lithium in rats. Forty Wistar male rats were randomized into four groups: control groups fed ad libitum powered standard diet for 1 and 3 months and experimental groups fed ad libitum the same diet supplemented with 60 mmol/kg diet for 1 and 3 months. Histopathological changes, laboratory parameters, and oxidative stress measurements were assessed at months 1 and 3. The experimental animals showed alteration of the cortical tubules from the first month of lithium-treatment and a decrease in the glomerular filtration rate and in the glomerular area at the third month. There was an increase in thiobarbituric acid reactive substances and carbonyls, as well as an increase in reduced glutathione, in the kidney of rats exposed to lithium. These changes were evident from the first month of treatment and remained throughout the experiment. Our results suggest that, oxidative stress could be one of the pathogenic mechanisms involved in the structural and functional alterations of the kidney associated with prolonged use of lithium. The study of the pathogenic mechanisms involved in lithium-induced nephropathy is a critical issue for the development of new strategies for prevention and/or early detection.
Assuntos
Nefropatias/sangue , Nefropatias/induzido quimicamente , Lítio/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Animais , Taxa de Filtração Glomerular/efeitos dos fármacos , Glutationa/metabolismo , Glomérulos Renais/efeitos dos fármacos , Glomérulos Renais/metabolismo , Masculino , Ratos , Ratos Wistar , Insuficiência Renal/sangue , Insuficiência Renal/induzido quimicamente , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
Ischemic postconditioning (PostC) reduces infarct size in healthy experimental models. However, if protective effects of PostC are abolished during early stages of atherosclerotic and if this is related with a disbalance in mitochondrial energetics and alterations in thioredoxin-1 (Trx1) is still unknown. The objectives were to generate a murine high-fat diet (HFD)-fed model that developed in a phenotype consistent with early stages of atherosclerosis to then evaluate whether HFD exposure increased oxidative stress and consequently abolished the cardioprotection conferred by PostC. We used C57/BL6 mice fed with control diet (CD) or HFD for 12 weeks. Isolated mice hearts were subjected to 30 min of ischemia and 120 min of reperfusion (I/R group). For PostC group, after ischemia, six cycles of reperfusion/ischemia were performed (10 s per cycle) at the onset of reperfusion. In CD group, the PostC reduced infarct size (CD-I/R: 52.14 ± 2.8 vs. CD-PostC: 36.58 ± 1.8, P < 0.05) and increased phosphorylation of GSK3ß (CD-PostC: 2.341 ± 1.03 vs. CD-Baseline: 0.923 ± 0.41 AUOD, P < 0.05), and this cardioprotection was abolished in HFD-exposed mice. HFD increased hydrogen peroxide levels, produced a shift towards an oxidized intracellular environment (GSSG/GSH2), and increased Trx1 expression with higher fractions of oxidized protein. State 3 mitochondrial oxygen consumption in basal conditions decreased 24% in HFD-exposed mice and PostC improved state 3 values only in CD mice. Cellular redox state and mitochondrial bioenergetics were altered in HFD-exposed mice. We demonstrated that alterations in redox state at early stages of atherosclerosis abolished cardioprotective mechanisms, such as those induced by PostC, even with increased Trx1 levels.
Assuntos
Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Pós-Condicionamento Isquêmico , Traumatismo por Reperfusão Miocárdica/etiologia , Tiorredoxinas/metabolismo , Animais , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Traumatismo por Reperfusão Miocárdica/prevenção & controle , OxirreduçãoRESUMO
Lithium has been approved for the treatment of bipolar disorder since the 1970s and even today it is considered a first-line drug for the treatment of this disease. As bipolar disorder often begins between 15-35 years of age and requires long-term treatment, the assessment of the adverse effects of the drugs used is critical. Recently, there has been renewed interest on the risk of chronic kidney disease and kidney failure induced by lithium, with findings suggesting that both complications could be more frequent than previously considered. These data have led to question traditional measures of monitoring renal function such as levels of urea and creatinine, which show signifcant increases only after an important reduction of the glomerular filtration rate. Preliminary data have suggested that certain biomarkers of kidney injury, such as neutrophil gelatinase-associated lipocalin, may be more sensitive indicators of renal damage. The use of new biomarkers that allow early detection of kidney damage could be useful for the monitoring of patients treated with lithium.
Assuntos
Compostos de Lítio/efeitos adversos , Insuficiência Renal Crônica/induzido quimicamente , Insuficiência Renal/induzido quimicamente , Humanos , Testes de Função Renal , Insuficiência Renal/diagnóstico , Insuficiência Renal Crônica/diagnósticoRESUMO
Weanling rats fed a choline-deficient diet develop kidney oxidative damage, tubular and cortical kidney necrosis, renal failure and animal death. The effect of dietary menhaden oil was assayed on the mentioned sequence correlating oxidative stress with renal structure and function. Rats were fed ad libitum 4 different diets: (a) a choline-deficient diet with corn oil and sunflower hydrogenated oil as a source of fatty acids; (b) the same diet supplemented with choline; (c) a choline-deficient diet with menhaden oil as a source of fatty acids; and (d) the previous diet supplemented with choline. Animals were sacrificed at days 0, 2, 4 and 7. The histopathological study of the kidneys showed that renal necrosis was only observed at day 7 in choline-deficient rats receiving the vegetable oil diet, simultaneously with increased creatinine plasma levels. Homogenate chemiluminescence (BOOH-initiated chemiluminescence) and phospholipid oxidation indicate the development of oxidative stress and damage in choline-deficient rats fed vegetable oils as well as the protective effect of menhaden oil. Rats fed with the fish oil diet showed that oxidative stress and damage develop later, as compared with vegetable oil, with no morphological damage during the experimental period.
Assuntos
Deficiência de Colina/tratamento farmacológico , Colina/administração & dosagem , Suplementos Nutricionais , Óleos de Peixe/administração & dosagem , Nefropatias/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Doença Aguda , Animais , Deficiência de Colina/complicações , Deficiência de Colina/patologia , Óleo de Milho/administração & dosagem , Creatinina/sangue , Dieta , Rim/efeitos dos fármacos , Rim/patologia , Nefropatias/etiologia , Nefropatias/patologia , Masculino , Necrose , Fosfolipídeos/metabolismo , Óleos de Plantas/administração & dosagem , Ratos , Ratos Wistar , Óleo de GirassolRESUMO
Weanling Sprague-Dawley rats were fed on a choline-deficient diet with hydrogenated vegetable oil and corn oil as lipids develop acute renal failure. Pathogenesis of the latter is controversial and an ischemic mechanism has been proposed. Arachidonic acid derivatives are involved in the regulation of vascular tonus. Vasospasm could be due to an increase in tromboxane A2-mediated vasoconstriction or to a decrease in prostacyclin-induced vasodilatation. Enzymes involved in the synthesis of both compounds are tromboxane A2- and prostacyclin-synthase respectively. The aim of this study was to identify the variable number tandem repeats (VNTR) in the promoter region of prostacyclin synthase gene and verify if there exists a relationship between the occurrence of VNTR in those choline-deficient rats which die because of acute renal failure and those which do not. We verified the presence of the VNTR in the prostacyclin synthase rat gene, but we did not find any difference in the molecular weight of the alleles between experimental and control rats. Renal reparation of the acute kidney injury due to choline deficiency in some rats is not related with differences in VNTR in the promoter region of the prostacyclin synthase gene.
Assuntos
Deficiência de Colina/genética , Sistema Enzimático do Citocromo P-450/genética , Oxirredutases Intramoleculares/genética , Repetições Minissatélites , Regiões Promotoras Genéticas , Injúria Renal Aguda/fisiopatologia , Animais , Dieta , Feminino , Humanos , Masculino , Gravidez , Ratos , Ratos Sprague-DawleyRESUMO
Weanling Sprague-Dawley rats were fed on a choline-deficient diet with hydrogenated vegetable oil and corn oil as lipids develop acute renal failure. Pathogenesis of the latter is controversial and an ischemic mechanism has been proposed. Arachidonic acid derivatives are involved in the regulation of vascular tonus. Vasospasm could be due to an increase in tromboxane A2-mediated vasoconstriction or to a decrease in prostacyclin-induced vasodilatation. Enzymes involved in the synthesis of both compounds are tromboxane A2- and prostacyclin-synthase respectively. The aim of this study was to identify the variable number tandem repeats (VNTR) in the promoter region of prostacyclin synthase gene and verify if there exists a relationship between the occurrence of VNTR in those choline-deficient rats which die because of acute renal failure and those which do not. We verified the presence of the VNTR in the prostacyclin synthase rat gene, but we did not find any difference in the molecular weight of the alleles between experimental and control rats. Renal reparation of the acute kidney injury due to choline deficiency in some rats is not related with differences in VNTR in the promoter region of the prostacyclin synthase gene.
Assuntos
Humanos , Masculino , Animais , Feminino , Gravidez , Ratos , Deficiência de Colina/genética , Oxirredutases Intramoleculares/genética , /genética , Dieta , Repetições Minissatélites , Ratos Sprague-DawleyRESUMO
Weanling Sprague-Dawley rats were fed on a choline-deficient diet with hydrogenated vegetable oil and corn oil as lipids develop acute renal failure. Pathogenesis of the latter is controversial and an ischemic mechanism has been proposed. Arachidonic acid derivatives are involved in the regulation of vascular tonus. Vasospasm could be due to an increase in tromboxane A2-mediated vasoconstriction or to a decrease in prostacyclin-induced vasodilatation. Enzymes involved in the synthesis of both compounds are tromboxane A2- and prostacyclin-synthase respectively. The aim of this study was to identify the variable number tandem repeats (VNTR) in the promoter region of prostacyclin synthase gene and verify if there exists a relationship between the occurrence of VNTR in those choline-deficient rats which die because of acute renal failure and those which do not. We verified the presence of the VNTR in the prostacyclin synthase rat gene, but we did not find any difference in the molecular weight of the alleles between experimental and control rats. Renal reparation of the acute kidney injury due to choline deficiency in some rats is not related with differences in VNTR in the promoter region of the prostacyclin synthase gene.(AU)
Assuntos
Humanos , Masculino , Animais , Feminino , Gravidez , Ratos , Deficiência de Colina/genética , Sistema Enzimático do Citocromo P-450/genética , Oxirredutases Intramoleculares/genética , Dieta , Repetições Minissatélites , Ratos Sprague-DawleyRESUMO
Some aspects of the functional, morphological, and morphometrical characteristics of chronic progressive nephropathy occurring in 18- to 26-month-old male rats and in 3-month-old control rats were studied. Rats with chronic progressive nephropathy were proteinuric and showed a slight increase in serum creatinine and no changes in blood pressure. The morphological changes were studied by light microscopy, high-resolution light microscopy, and electron microscopy. They showed focal and segmental or global glomerulosclerosis, the three types of atrophic tubules ("classic," "thyroid-like," and "endocrine") described by Nadasdy et al, as well as interstitial fibrosis with mononuclear cell infiltrates. On certain occasions, small vessels showed hyalinosis. Glomerular morphometrical studies showed a biphasic pattern in the glomeruli progressing toward obsolescence. Vascular morphometrical studies showed significant increase in media wall thickness and media cross-sectional area in the 18- to 26-month-old rats. These results support the hypothesis that changes in the vascular system are not of utmost importance in the pathogenesis of chronic progressive nephropathy, and that glomerular sequential changes seem to be of paramount significance in the progression of the disease.