Mechanisms of the beneficial effect of sevoflurane in liver ischemia/reperfusion injury

PURPOSE: To evaluate the underlying mechanisms by which sevoflurane protects the liver against ischemia/reperfusion injury evaluate the mechanism by which sevoflurane exerts this protective effect. METHODS: Twenty-six rats were subjected to partial ischemia/reperfusion injury for 1h: one group received no treatment, one group received sevoflurane, and sham group of animals received laparotomy only. Four hours after reperfusion, levels of alanine and aspartate aminotransferases, tumor necrosis factor-a, and interleukins 6 and 10 were measured. Analyses of mitochondrial oxidation and phosphorylation, malondialdehyde content, histology, and pulmonary vascular permeability were performed. RESULTS: Serum levels of alanine and aspartate aminotransferases were significantly lower in the sevoflurane group compared to untreated controls (p<0.05). The sevoflurane group also showed preservation of liver mitochondrial function compared to untreated controls (p<0.05). Sevoflurane administration did not alter increases in serum levels of tumor necrosis factor-a, and interleukins 6 and 10. Sevoflurane treatment significantly reduced the coagulative necrosis induced by ischemia/reperfusion (p<0.05). Pulmonary vascular permeability was preserved in the sevoflurane group compared to untreated controls. CONCLUSION: Sevoflurane administration protects the liver against ischemia/reperfusion injury, via preservation of mitochondrial function, and also preserves lung vascular permeability.

Effects of hyperbaric oxygen therapy on the liver after injury caused by the hepatic ischemia-reperfusion process

PURPOSE: To evaluate the effects of hyperbaric oxygen on rats submitted to hepatic ischemia and reperfusion. METHODS: Twenty-three Wistar rats were divided at random into 3 groups: SHAM, rats submitted to surgical and anesthetic stress without induction of hepatic ischemia/reperfurion; I/R, rats submitted to total ischemia of the hepatic pedicle for 25 min followed by 5 min of reperfusion; HBOI/R, rats submitted to 60 min of hyperbaric oxygen therapy at a pressure of 2 absolute atmospheres immediately after the experimental protocol of ischemia/reperfusion. Hepatic function was evaluated by quantitation of serum alanine aminotranferase (ALT) and aspartate aminotransferase (AST), and by mitochondrial function through the determination of states 3 and 4 of mitochondrial respiration, respiratory control ratio (RCR) and mitochondrial swelling. Data were analyzed by the Mann-Whitney test, with the level of significance set at p <0.05. RESULTS: There was a significant difference in state 3 values for the SHAM group vs I/R and I/R vs IRHBO, in state 4 values for the SHAM group vs I/R; and in mitochondrial swelling for the SHAM groups vs I/RHBO, SHAM vs I/R, and IR vs I/RHBO. CONCLUSION: The use of hyperbaric oxygen after I/R improved in a relative manner both the production of energy and the effects on the mitochondrial wall. .

Effect of hyperbaric hepatic hyperoxia on the liver of rats submitted to intermittent ischemia/reperfusion injury

PURPOSE: To determine the effect of hyperbaric hyperoxia as hepatic preconditioning on hepatocellular integrity in rats submitted to intermittent hepatic ischemia/reperfusion injury. METHODS: Twenty male Wistar rats were divided into 4 groups (SHAM, I/R, HBO-I/R and CONTROL). The surgical technique consisted of total clamping of the hepatic pedicle for 15 min, followed by reperfusion for 5 min, performed twice. The application of hyperbaric oxygen (HBO) was carried out in a collective chamber (simultaneous exposure of 4 rats) pressurized directly with oxygen at 2 ATA for 60 min. Tissue malondialdehyde (MDA) levels were determined and blood samples were collected for the determination of serum AST and ALT levels. Data were analyzed statistically by the Mann-Whitney test, with the level of significance set at p < 0.05. RESULTS: A statistically significant difference in MDA (p< 0.05) was observed between control and HBO-I/R, but not between control and I/R. Regarding AST, there was a difference between control and I/R and HBO-I/R. Analysis of ALT revealed a significant difference between control and I/R (p<0.05) and between I/R and HBO-I/R, with no difference between control and HBO-IR. CONCLUSION: Hyperoxic preconditioning proved to be favorable regarding alanine transaminase, but not aspartate aminotranserase or malondialdehyde levels. .

Hyperoxic preconditioning in partial liver ischemia

PURPOSE: To evaluate the effect of the hyperbaric oxygen (HBO) treatment as a pre-conditioning for I/R effects in the liver ischemia. METHODS: Fifty-seven male Wistar rats (260-300g) were submitted to the following procedures: SHAM; I/R, rats submitted to I/R, consisting of partial ischemia of 70% of the liver for 90 minutes followed by 15 minutes of reperfusion; HBO I/R 1 ATA, 30 minutes of HBO treatment at the pressure of 1 absolute atmosphere (ATA) during the ischemia time. HBO I/R 2 ATA, 30 minutes of HBO (2 ATA) during the ischemia time. Pre HBO I/R 30', rats submitted to 30 minutes of HBO (2 ATA) immediately before the I/R time. Pre HBO I/R 90', rats submitted to 90 minutes of HBO (2 ATA) immediately before the I/R time. RESULTS: There was a significant worsening of all the parameters of mitochondrial energy production (state 3, 4, RCR and Swelling) in the I/R group, when compared to the Sham group (I/R <Sham, p<0.05). There was also a significant worsening in state 4, RCR and mitochondrial edema in the Pre HBO I/R 90' group compared to the I/R group. Hepatic enzyme concentrations were significantly higher in the I/R group. CONCLUSION: The use of hyperbaric oxygen before and during I/R did not improve the production of hepatocellular energy reduced by I/R, nor did it prevent the installation of mitochondrial edema induced by Iischemia/reperfusion. .

Effects of hyperbaric oxygen therapy as hepatic preconditioning in rats submitted to hepatic ischemia/reperfusion injury

PURPOSE: To analyze the role of hyperbaric oxygen therapy as hepatic preconditioning in rats submitted to hepatic ischemia and reperfusion. METHODS: Wistar rats were randomly divided into three groups: SHAM, rats submitted to surgical stress without hepatic ischemia and reperfusion, I/R, rats submitted to total hepatic pedicle ischemia for 30 min, followed by 5 min of reperfusion; HBOI/R, rats submitted to 60 minutes of hyperbaric oxygen therapy at 2 atm and immediately submitted to the experimental protocol of ischemia and reperfusion. Liver function was assessed by measuring serum alanine aminotransferase and aspartate aminotransferase, as well as mitochondrial function by determining states 3 and 4 of mitochondrial respiration, respiratory control rate and mitochondrial permeability transition (mitochondrial swelling). The results were analyzed by the Mann-Whitney test and all P-values <0.05 were considered significant. RESULTS: There were significant differences in serum aspartate aminotransferase values in groups SHAM vs. HBOI/R, I/R vs HBOI/R, alanine aminotranferase in groups SHAM and I/R; State 3 in SHAM groups vs. I/R, SHAM vs. HBOI/R, State 4 in I/R vs HBOI/R groups, respiratory control rate in SHAM vs I/R groups; mitochondrial swelling in SHAM vs. I/R groups, and SHAM vs HBOI/R. CONCLUSION: Hyperbaric preconditioning improved hepatic mitochondrial function and decreased serum markers of liver injury in the ischemia and reperfusion process. .

Effect of hyperbaric oxygen therapy on liver function during intermittent ischemia / Efeito da oxigenoterapia hiperbárica sobre a função hepática na isquemia intermitente

PURPOSE: To analyze the effects of hyperbaric oxygen therapy on liver function in rats previously subjected to ischemia and reperfusion. METHODS: A randomly distribution of 23 Wistar rats was conducted into three groups: SHAM, animals subjected to surgical stress without restricting blood flow by clamping the hepatic pedicle, IR, rats underwent hepatic vascular occlusion intermittently for two complete cycles of 15 minutes of ischemia followed by 5 min of reperfusion, IR / HBO, rats underwent hepatic pedicle clamping and thereafter exposed to hyperbaric oxygen pressure of 2 absolute atmospheres for 60 minutes. We evaluated liver function through mitochondrial function, determined by the stages 3 and 4 of respiration, respiratory control ratio (RCR) and mitochondrial permeability transition (Swelling). Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were also quantified . We analyzed the results using the Mann-Whitney test and were considered significant all results with p <0.05. RESULTS: There were significant differences between the results of stage 3 in SHAM vs IR group ; of the stage 4 in the groups IR vs SHAM and SHAM vs IR /HBO; of the Respiratory Control Ratio (RCR) in the group IR vs IR / HBO ; of alanine aminotransferase in the groups IR vs SHAM , SHAM vs IR/HBO and IR vs IR / HBO; aspartate aminotransferase in the groups SHAM vs IR and SHAM vs IR / HBO. CONCLUSION: The whole analysis of the mitochondiral function indicators permits us to conclude that the hyperbaric oxygen therapy acted as a protective agent of the mitochondrial function, minimizing the ischemia-reperfusion injury of the hepatic parenchyma.

OBJETIVO: Analisar os efeitos da oxigenoterapia hiperbárica sobre a função hepática de ratos previamente submetidos à isquemia e reperfusão. MÉTODOS: Realizou-se a distribuição aleatória de 23 ratos Wistar em três grupos: SHAM, animais submetidos ao estresse cirúrgico sem restrição de fluxo sanguíneo por clampeamento do pedículo hepático; IR ratos submetidos a oclusão vascular hepática de maneira intermitente em dois ciclos completos de 15 minutos de isquemia, seguidos por 5 min de reperfusão; IR/HBO, ratos submetidos ao clampeamento do pedículo hepático e ,ulteriormente , expostos a oxigenoterapia hiperbárica a pressão de 2 atmosferas absolutas durante 60 minutos. Avaliou-se a função hepática através da função mitocondrial, determinada pelos estados 3 e 4 da respiração mitocondrial, razão de controle respiratório(RCR) e transição de permeabilidade mitocondrial (Swelling) .Quantificou-se também alanina aminotransferase e aspartato aminotransferase séricas. Analisou-se os resultados pelo teste de Mann-Whitney e foram considerados significativos os valores de p < 0,05. RESULTADOS:Houve diferença significativa nos valores do estado 3 no grupo SHAM vs IR; estado 4 nos grupos SHAM vs IR, SHAM vsIR/HBO; Razão de Controle Respiratório(RCR) no grupo IR vs IR/HBO; alanina aminotransferase nos grupos SHAM vs IR, SHAM vs IR/HBO, IR vs IR/HBO; aspartato aminotransferase nos grupos SHAM vs IR , SHAM vs IR/HBO. CONCLUSÃO: A análise dos parâmetros mitocondriais como um todo permitiu concluir que a oxigenoterapia hiperbárica atuou como agente protetor da função mitocondrial, minimizando os efeitos deletérios da lesão de isquemia e reperfusão do parênquima hepático.

Effects of hyperbaric oxygen (HBO), as pre-conditioning in liver of rats submitted to periodic liver ischemia/reperfusion / Efeitos da oxigenoterapia hiperbárica como pré-condicionamento em fígados de ratos submetidos à lesão hepática de isquemia/reperfusão intermitente

PURPOSE: to assess the effect of hyperbaric oxygen (HBO) as pre-conditioning on periodic liver ischemia/reperfusion injury. METHODS: Thirty-six male Wistar rats were divided into 4 groups (SHAM, I/R , HBO-I/R and CONTROL). The surgical technique consisted of total clamping of the hepatic pedicle for 15 min followed by twice repeated reperfusion for 5 min (unclamping). HBO was applied in a collective chamber (simultaneous exposure of 4 rats) directly pressurized with oxygen at 2 ATA for 60 min. Hepatic mitochondrial function was determined using samples of the median lobe obtained after exactly 5 min of reperfusion for the analysis of mitochondrial respiration based on the determination of states 3 and 4, the respiratory control ratio and the transition of mitochondrial permeability (mitochondrial swelling).Data were analyzed by the Mann-Whitney test and the level of significance was set at p < 0.05. RESULTS: There was a statistically significant difference (p< 0.05) in state 3 between the CONTROL and I/R and HBO-I/R groups, in state 4 between the CONTROL and I/R and HBO-I/R groups; in respiratory control ratio (RCR) between the CONTROL and I/R and HBO-I/R groups and between the CONTROL and Sham groups, and in mitochondrial swelling between the CONTROL and I/R and HBO-/R groups and between the Sham and I/R and HBO-I/R groups. CONCLUSION: In this process of periodic ischemia and reperfusion, hyperbaric pre-conditioning did not improve significantly hepatic mitochondrial function.

OBJETIVO: Avaliar os efeitos da oxigenoterapia hiperbárica (HBO), como pré-condicionamento, em lesão hepática de isquemia/reperfusão intermitente. MÉTODOS: Foram avaliados 36 ratos Wistar machos, distribuídos em 4 grupos (SHAM, I/R , HBO - I/R e CONTROLE). A técnica operatória consistiu em pinçamento total do pedículo hepático durante 15min, seguido de reperfusão por 5 min (desclampeamento), por duas vezes. A aplicação de HBO foi realizada em câmara coletiva (exposição simultânea de 4 ratos) diretamente pressurizada com oxigênio a 2ATA, durante 60min. Determinou-se a função mitocondrial hepática através de amostras do lobo mediano colhidas com exatos 5min de reperfusão para análise da respiração mitocondrial, através da determinação dos estados 3 e 4, razão de controle respiratório e transição de permeabilidade mitocondrial (intumescimento osmótico - swelling mitocondrial).Os resultados foram analisados pelo teste de Mann-Whitney e foi considerado significativo todo valor de p < 0,05. RESULTADOS: Houve diferença estatistica significativa (p< 0,05) no Estado 3 nos grupos CONTROLE vs I/R e HBO - I/R, no Estado 4 nos grupos CONTROLE vs I/R e HBO - I/R; na Razão de controle respiratório(RCR) nos grupos CONTROLE vs I/R e HBO-IRe CONTROLE vs Sham e no Swelling mitocondrial nos grupos CONTROLE vs I/R e HBO - I/R, I/R vs HBO-IRe Sham vs I/R e HBO-IR. CONCLUSÃO: O pré-condicionamento hiperbárico não melhorou a função mitocondrial hepática significativamente neste processo de isquemia e reperfusão intermitente.

Lovastatin protects mithochondrial and renal function in kidney ischemia-reperfusion in rats / Lovastatina protege a função renal e mitocondrial na isquemia/reperfusão renal em ratos

PURPOSE: To investigate the effect of lovastatin on renal ischemia followed by reperfusion. METHODS: Thirty one Wistar rats submitted to left renal ischemia for 60 minutes followed by contralateral nephrectomy were divided into two groups: A (n =17, control, no treatment), and B (n=14, lovastatin 15 mg/kg/day p.o. ten days before ischemia). The animals were sacrificed at the end of ischemia, after 24 hours and at seven days after reperfusion. Survival, serum urea and creatinine levels and renal mitochondrial function were evaluated. RESULTS: Mortality was 29.4% in group A and 0.7% in group B. Urea and creatinine levels were increased in both groups, but the values were significantly lower in group B. Mitochondrial function showed decoupling in 83.4% of group A, as opposed to 38.4/% of group B. CONCLUSIONS: The result shows a protective action of renal function by lovastatin administered before ischemia/reperfusion. Since most of the mitochondrial fraction presented membranes with the ability to maintain ATP production in group B, stabilization of the mitochondrial membrane should be considered as part of the protective action of lovastatin on renal function in ischemia/reperfusion.

OBJETIVO: Investigar a ação da lovastatina na isquemia renal seguida de reperfusão. MÉTODOS: Trinta e um ratos Wistar submetidos à isquemia renal esquerda durante 60 minutos, seguida da nefrectomia contralateral, foram distribuídos em dois grupos: A (n=17, controle, sem tratamento) e B (n=14, recebendo 15 mg/Kg/dia de lovastatina via oral), durante os dez dias que antecederam a isquemia. Os animais foram mortos ao final da isquemia, e com 24 horas e sete dias após a reperfusão. Foram avaliadas a sobrevida, os valores séricos de uréia e creatinina e a função mitocondrial renal. RESULTADOS: A mortalidade foi 29,4% no grupo A e 0,7% no grupo B. Os níveis de uréia e creatinina elevaram-se nos dois grupos, mas foram significativamente menores no grupo B. No grupo A a função mitocondrial renal ficou desacoplada em 83,4% dos ensaios, enquanto que no grupo B isto ocorreu em apenas 38,4% dos ensaios. CONCLUSÕES: Os resultados mostram que a administração de lovastatina antes do episódio de isquemia protege a função renal. No grupo B, como a maior parte da fração mitocondrial isolada apresentou função acoplada à produção de ATP, deve-se também considerar a estabilização da membrana mitocondrial como parte da ação protetora da lovastatina na função renal durante isquemia e reperfusão.

Biochemical liver function after partial hepatic resection with or without partial hepatic vascular exclusion / Função bioquímica do fígado após ressecção hepática parcial com ou sem exclusão vascular hepática parcial

PURPOSE: The aim of the present study was to assess the advantages and disadvantages of liver vascular partial exclusion (LVPE) (liver dysfunction due to ischemia) during liver resection in patients submitted to partial hepatectomy. METHODS: A total of 114 patients were submitted to partial hepatectomy (minor versus major resections) with LPVE being used in 57 of them but not in the remaining 57. Patient age ranged from 35 to 73 years and 57 percent were women. Mitochondrial function was assessed 30 minutes after liver resection in the remnant liver and serum aminotransferases were determined before surgery and for seven days postoperatively. LPVE time ranged from 30 to 60 minutes. Data were analyzed statistically by the Student T test (5 percent level of significance). RESULTS: Mitochondrial function was similar in the minor and major liver resections. The maximum postoperative aminotransferase peak was similar in the groups with and without LPVE. CONCLUSION: LPVE did not induce mitochondrial changes in hepatic tissue in either type of surgery, and aminotransferase levels were similar for patients with and without LPVE. Thus, the results show that LPVE is a safe procedure that does not induce the significant changes typical of ischemia and reperfusion in the liver remnant.

OBJETIVO: Avaliar as vantagens e desvantagens da oclusão vascular parcial do fígado durante ressecções hepáticas parciais. MÉTODOS: Cento e quatorze pacientes foram submetidos a hepatectomia parcial(ressecção maior versus ressecção menor) com liver partial vascular exclusion (LPVE) sendo utilizada em 57 deles. A idade dos pacientes variou entre 35 e 73 anos e 57 por cento deles eram mulheres. A função mitocondrial foi avaliada por método polarografico avaliada 30 minutos após a ressecção hepática no fígado remanescente, e o perfil das aminotransferase foi determinado antes da cirurgia e durante sete dias de pós-operatório. A EVPH variou de 30 a 60 minutos. Dados foram analisados estatisticamente pelo teste T Student (nível de significância de 5 por cento). RESULTADOS: Nas ressecções hepáticas maiores e menores, a função mitocondrial do fígado remanescente foi semelhante dos dois grupos. O pico máximo de aminotransferases ocorreu as 24 horas de pós-operatório e o perfil enzimático de ALT e AST foi semelhante nos grupos estudados ( minor vs major hepatectomy.) CONCLUSÃO: A EVPH não induziu alterações mitocondriais no tecido hepático em qualquer tipo de cirurgia, e os níveis de aminotransferases foram similares para pacientes hepatectomizados com e sem LPVE.Assim a LPVE foi um procedimento seguro que não induziu alterações significativas típicos de isquemia e reperfusão no fígado remanescente.

Obstructive jaundice induces early depression of mitochondrial respiration in rat hepatocytes / A icterícia obstrutiva induz depressão precoce da respiração mitocondrial em hepatócitos de ratos

INTRODUCTION: Oxidative phosphorylation dysfunction of hepatocyte mitochondria is involved in the pathophysiology of organ dysfunction following obstructive jaundice (OJ). However the time period from biliary occlusion to the occurrence of the dysfunction has not been determined decisively. PURPOSE: To evaluate the early effects (1 d and 7 d) of OJ on liver mitochondria respiratory function in rats. METHODS: Male Wistar rats (200-250 g) were randomly divided into the following 3 groups: laparotomy plus OJ for 24 h (1d group) (n = 10); laparotomy plus OJ for 7 d (7d group) (n = 10); sham control procedure (CTR group) (n = 12). At the end of OJ periods, total serum bilirubin level, hepatic enzyme activity levels (GOT, GTP, Gama-GT, ALP), mitochondrial respiration phases S3 and S4, as well as the respiratory control ratio (RC = S3/S4), and ADP consumption/oxygen consumption (ADP/O) ratio, were determined. RESULTS: Total serum bilirubin, activity of most hepatic enzymes, and O2 consumption during basal (S4) respiration were increased in the 1d and 7d groups (ANOVA, p = 0.05 vs. CTR). After ADP addition, the O2 consumption rate (S3) in the 1d group remained similar to the CTR rate (ANOVA p > .05), while the RC rate was reduced (ANOVA, p = 0.001) vs. CTR. The effects observed on mitochondrial respiration in the 1d group were exacerbated in the 7d group. CONCLUSION: These results indicate that OJ induces early (24 h) depression of liver mitochondria respiration, and thus may lead to early reduction in the production of high energy bonds.

INTRODUÇÃO: A disfunção da fosforilação oxidativa das mitocôndrias do hepatócito está envolvida na fisiopatologia da disfunção orgânica subseqüente à icterícia obstrutiva (IO). Entretanto, a precocidade da ocorrência desta disfunção permanece obscura. OBJETIVO: Avaliar o efeito precoce da IO na função respiratória mitocondrial em ratos. MÉTODOS: Ratos Wistar machos (200 a 250g) foram randomizados em 3 grupos que foram submetidos a laparotomia mais: IO por 24hs (grupo 1d)(n=10); IO por 7 dias (grupo 7d)(n=10; procedimento simulado (grupo CTR)(n=12). Ao final dos períodos de IO, foram determinados: bilirrubina sérica total, atividade de enzimas hepáticas (TGO, TGP, Gama-GT, FA), e as fases S3 e S4 da respiração mitocondrial, bem como o razão do controle respiratório (RC = S3/S4), e a razão entre consumo de ADP/consumo de oxigênio (ADP/O). RESULTADOS: Observou-se significativo aumento de bilirrubina sérica total, enzimas hepáticas, e consumo de O2 durante a respiração basal (S4) no grupo de IO por 24hs (ANOVA, p=0.009). Após adição de ADP, a taxa de consumo de O2 (S3) não diminuiu significativamente no grupo de IO, comparado com o CTR (ANOVA, p>0.05); entretanto, a razão do controle respiratório (RC) foi significativamente mais baixa comparada com o CTR (ANOVA, p=0.001). Os efeitos observados na respiração mitocondrial no grupo do dia 1d estavam exacerbados no grupo 7d. CONCLUSÃO: Estes resultados indicam que a icterícia obstrutiva induz depressão precoce (24hs) da respiração mitocondrial, e pode assim levar à redução da produção de ligações de alta energia.

The use of light-emitting diodes to stimulate mitochondrial function and liver regeneration of partially hepatectomized rats

The biostimulating effect of laser radiation has been observed in many areas of Medicine. However, there are still several questions to be answered, among them the importance of light coherence in the stimulatory process. In the present study, we used light-emitting diodes (LED) to promote the stimulation of liver regeneration after partial hepatectomy in rats. Fourteen male Wistar rats weighing 200-250 g were submitted to partial hepatectomy (70 percent) followed by LED light irradiation (630 nm) of the remaining part of the liver at two doses, i.e., 10 (N = 7) and 140 (N = 7) J/cm². A group irradiated with laser, 590 nm (N = 7, 15 J/cm²) was performed for the study of proliferating cell nuclear antigen-labeling index. Data are reported as mean ± SEM. Statistical comparisons of the groups were performed by analysis of variance for parametric measurements followed by the Bonferroni post-test, with the level of significance set at P < 0.05. Respiratory mitochondrial activity was increased in the irradiated groups (states 3 and 4; P < 0.05), with better results for the group exposed to the lower LED dose (10 J/cm²). The proliferating cell nuclear antigen-labeling index, by immunohistochemical staining, was similar for both LED-exposed groups (P > 0.05) and higher than for the control group (P < 0.05). The cell proliferation index obtained with LED and laser were similar (P > 0.05). In conclusion, the present results suggest that LED irradiation promotes biological stimulatory effects during the early stage of liver regeneration and that LED is as effective as laser light, independent of the coherence, divergence and cromaticity.

Liver mitochondrial dysfunction and oxidative stress in the pathogenesis of experimental nonalcoholic fatty liver disease

Oxidative stress and hepatic mitochondria play a role in the pathogenesis of nonalcoholic fatty liver disease. The aim of the present study was to evaluate the role of hepatic mitochondrial dysfunction and oxidative stress in the pathogenesis of the disease. Fatty liver was induced in Wistar rats with a choline-deficient diet (CD; N = 7) or a high-fat diet enriched with PUFAs-omega-3 (H; N = 7) for 4 weeks. The control group (N = 7) was fed a standard diet. Liver mitochondrial oxidation and phosphorylation were measured polarographically and oxidative stress was estimated on the basis of malondialdehyde and glutathione concentrations. Moderate macrovacuolar liver steatosis was observed in the CD group and mild liver steatosis was observed in the periportal area in the H group. There was an increase in the oxygen consumption rate by liver mitochondria in respiratory state 4 (S4) and a decrease in respiratory control rate (RCR) in the CD group (S4: 32.70 ± 3.35; RCR: 2.55 ± 0.15 ng atoms of O2 min-1 mg protein-1) when compared to the H and control groups (S4: 23.09 ± 1.53, 17.04 ± 2.03, RCR: 3.15 ± 0.15, 3.68 ± 0.15 ng atoms of O2 min-1 mg protein-1, respectively), P < 0.05. Hepatic lipoperoxide concentrations were significantly increased and the concentration of reduced glutathione was significantly reduced in the CD group. A choline-deficient diet causes moderate steatosis with disruption of liver mitochondrial function and increased oxidative stress. These data suggest that lipid peroxidation products can impair the flow of electrons along the respiratory chain, causing overreduction of respiratory chain components and enhanced mitochondrial reactive oxygen species. These findings are important in the pathogenesis of nonalcoholic fatty liver disease.

A atividade respiratória mitocondrial é um bom parâmetro para a lesão por isquemia e reperfusão hepática? / Is the mitochondrial respiratory activity a good parameter for hepatic ischemia and reperfusion injury?

RACIONAL: A atividade respiratória das mitocôndrias está associada à lesão por isquemia e reperfusão do fígado. OBJETIVO: Investigar in vitro se há obrigatoriedade de impedimento da respiração mitocondrial para que a lesão por isquemia e reperfusão do fígado possa ser detectada. MATERIAIS E MÉTODOS: Vinte e quatro cães de ambos os gêneros foram divididos nos seguintes grupos: controle, cães operados sem sofrer isquemia ou reperfusão hepática; I60, cães submetidos a 60 minutos de isquemia do fígado; I30/R60, cães submetidos a 30 minutos de isquemia e 60 minutos de reperfusão do fígado e I45/R120, cães submetidos a 45 minutos de isquemia e 120 de reperfusão do fígado. Amostras de fígado foram obtidas para dosagem de malondialdeído, para estudo da respiração mitocondrial por meio de traços polarográficos e para avaliação do potencial de membrana mitocondrial. Sangue foi obtido para dosagem de transaminases e desidrogenase lática. RESULTADOS: O grupo I45/R120 apresentou evidente aumento dos valores de transaminases, desidrogenase lática, aumento dos valores de malondialdeído e tendência à diminuição da respiração mitocondrial estimulada por adenosina difosfato, sem haver prejuízo irreversível para a fosforilação oxidativa ou para o potencial de membrana mitocondrial. CONCLUSÃO: A lesão por isquemia e reperfusão do fígado do cão pode ser documentada sem que haja prejuízo demonstrável para a função mitocondrial. Dados referentes à respiração mitocondrial podem não mostrar diferenças significativas em relação aos controles, mesmo em situações de evidente lesão tecidual por isquemia e reperfusão do fígado.

Behavior of cholinesterase and liver mitochondrial function in dogs submitted to normothermic ischemia and reperfusion

Purpose: The plasmatic activity of the cholinesterase (CHE) and the Tiver mitochondrial function, expressed by the ratio of respiratory control (RCR), were studied during normothermic ischemia. Methods: Sixteen adult mongrels, eight females and eight males were submitted to ischemia by clamping of the hepatic artery, portal vein and infrahepatic inferior vena cava, infra-hepatic, for two h, follwed by reperfusion for 1 h. The CHE and the mitochondrial function were evaluated at 60 and 120 min. of ischemia and at 15 and 60 minutes of reperfusion. Results: The CHE decreased, significandy, during ischemia and in reperfusion. The RCR was decreased at 120 min. of ischemia, returning to the initial values on reperfusion.Conclusion: In this study, the CHE was a sensitive indicator of ischemic injury , suggesting irreversibility of ischemia injury. The RCR, by other side, showed a greater sensibility than the CHE in detection sense, during the studied period, the reversibility of the hepatic ischemic injury.

Efeitos do extrato aquoso da hyptis pectinata sobre a regeneraçäo hepática após hepatectomia parcial de 70 por cento: resultados preliminares / Effects of the aqueous extract of hyptis pectinata on liver regeneration after 70 percent partial hepatectomy: preliminary results

O uso de plantas medicinais tem aumentado bastante na populaçäo mundial. O objetivo desta pesquisa é avaliar os efeitos do extrato aquoso das folhas da Hyptis pectinata, popularmente conhecida como "sambacaitá" ou "canudinho", sobre a regeneraçäo hepática após hepatectomia parcial de 70 por cento. Foram utilizados 24 ratos, divididos em 4 grupos: grupo OS, em que se realizou operaçäo simulada e aplicaçäo oral de água destilada por 4 dias; grupo OSD200, também submetido à laparotomia com manipulaçäo do fígado e aplicaçäo de 200 mg de extrato/Kg de animal durante o mesmo período; grupo HP, hepatectomizado a 70 por cento após 4 dias de aplicaçäo por via oral de água destilada; e grupo HPD200, hepatectomizado a 70 por cento após 4 dias de administraçäo de 200 mg extrato/Kg de animal. Foram dosadas fosfatase alcalina, bilirrubina total e as aminotransferases e estudou-se o estado III da funçäo mitocondrial. O grupo OSD200, quando comparado ao OS, apresentou reduçäo significativa da fosfatase alcalina. O grupo HPD200, em comparaçäo ao HP, teve reduçäo estatisticamente significativa no nível da AST e do estado III da funçäo mitocondrial.

Estudo do potencial de membrana mitocondrial em ratos cirróticos hepatectomizados após aplicaçäo de laser / Study of mitochondrial membrane potential in cirrhotic and hepatectomized rats after laser application

Através da determinaçäo do potencial de membrana mitocondrial, o presente estudo relata os efeitos da irradiaçäo laser sobre o estado energético do fígado cirrótico de ratos hepatectomizados. A cirrose hepática foi induzida por ligadura do ducto biliar comum. Os resultados revelaram melhora do status energético do fígado após irradiaçäo.

Avaliaçäo do intumescimento osmótico mitocondrial do fígado submetido a isquemia parcial e ao pré-condicionamento isquêmico / Evaluation of mitochondrial osmotic intumesciment of the liver submitted to partial ischemia to the ischemic preconditioning

O objetivo deste trabalho foi avaliar a permeabilidade da membrana mitocondrial em animais submetidos a pré-condicionamento isquêmico, isquemia e reperfusão seguido de hepatectomia a 70 por cento. Foram utilizados 30 ratos Wistar divididos em 3 grupos de 10: Grupo Controle (fc), Grupo Isquêmico (fi) e Grupo Pré-condicionado (fp). Após o procedimento cirúrgico os animais foram sacrificados para a remoção do remanescente hepático (30 por cento) do qual foram isoladas as mitocôndrias para a realização dos estudos de permeabilidade da membrana mitocondrial interna através do intumescimento osmótico. Foi observado um aumento significativo do intumescimento osmótico mitocondrial do grupo fi em relação aos grupos fc e fp, sugerindo uma possível participação de espécies reativas do oxigênio no processo.

Avaliação da funçäo mitocondrial hepática em crianças portadoras de colestase neonatal / Evaluation of hepatic mitocondrial function in infants with neonatal cholestasis

A dificuldade em se excluir o diagnóstico de atresia de vias biliares através de exames não invasivos freqüentemente leva à realização de biópsia hepática, cirúrgica ou transparietal. Apesar de inúmeros estudos a respeito de muitos de seus aspectos, esta moléstia ainda é considerada idiopática. Com a finalidade de compreender melhor as alterações hepáticas decorrentes da atresia de vias biliares, estudamos a função mitocondrial dos hepatócitos em crianças portadoras de colestase neonatal. Foram estudadas dez crianças portadoras de colestase neonatal, das quais sete foram submetidas à laparotomia para realização de biópsia hepática, colangiografia intra-operatória e portoenterostomia. Os valores obtidos para o consumo de oxigênio no estado 3 de ativação mitocondrial foram semelhantes aos de fígados normais, o que reflete uma boa capacidade de oxidação/fosforilação, transformando ADP em ATP. Estes resultados revelam uma capacidade compensatória mitocondrial para enfrentar a situação adversa conseqüente à doença hepática. Os valores para o estado 4 foram significativamente maiores que os de fígados normais, o que indica um aumento de permeabilidade de membrana mitocondrial. A diminuição do potencial de membrana, com lesão do tipo desacoplamento oxidação/fosforilação também sugere deficiência na capacidade energética dos hepatócitos. A diminuição da razão de controle respiratório foi outro achado significativo, que pode ser parte da alteração típica de colestase neonatal crônica, com algum grau de cirrose biliar.

Funçäo mitocondrial hepática compensatória na coletase extra hepática aguda / Compensatory hepatic mitochondrial function in acute extrahepatic cholestasis

A atividade compensatória mitocondrial é um mecanismo que permite a alguns orgãos manter seu nível energético em situações adversas. Este presente estudo visa analisar a função mitocondrial hepática em ratos submetidos à OBEH. Foram estudados 10 ratos Wistar machos (180 a 230 g), divididos em dois grupos. Grupo operação simulada - OS e grupo obstrução biliar extra hepática (OBEH). Após 24 h. foram coletadas amostras de sangue e biópsia hepática para a dosagem do nível sérico das enzimas hepáticas e a atividade mitocondrial. Houve aumento significativo das aminotranferases, da FA e BT (tabela 1).Verificou-se aumento do Estado 3 da respiração mitocondrial. Analisando os resultados, observou-se que as mitocôndrias hepáticas apresentaram atividade compensatória no sentido de preservação da função hepatocelular.

Aminotransferase levels in hypothermic preservation medium and liver mitochondrial function in acute extrahepatic biliary obstruction in rats

In acute extrahepatic biliary obstruction (AEBO), serum aminotransferase levels (ALT and AST) are similar to those observed in acute hepatitis (AH). Microscopically, the two pathologies have completely different characteristics, indicating the possibility that different mechanisms underlie the passage of aminotransferase from the intracellular to the intravascular medium. The objective of the present study was to assess serum ALT and AST levels in rats with AEBO and ALT and AST levels in preservation medium (PM) and the hepatic mitochondrial function before and after hypothermic (2-4ºC) liver preservation. Two sets of experiments were performed: The first set was conducted on 14 male Wistar rats (250-350g), 7 of them used as controls and 7 submitted to AEBO of 24-h duration. The second set was conducted on 14 male Wistar rats weighing 250-350 g divided into two groups of 7 animals, each, i. e., a control group (n=7) and an ischemic group. Before being submitted to hypotermic presevation, the animals were submitted to 1 hour of warm ischemia. After hepatectomy, the livers from all groups were preserved in Belzer UW solution at 2-4ºC for 3 h. The serum aminotransferase levels in the AEBO group were significantly increased to 1707 + 223 U/l for AST, 1522 + 45 U/l for ALT, and 1508 + 127 U/l for alkaline phosphatase when compared to the controls (P < 0.0001)...