ABSTRACT Purpose: After partial hepatectomy (PH), the remaining liver (RL) undergoes regenerative response proportional to the host. Limited literature exists on hepatic viability after tissue injury during hypothermic preservation. Spectroscopy measures cellular fluorescence and is explored for tissue characterization and parameter investigation. This study aimed to assess fluorescence analysis (spectroscopy) in evaluating liver viability and its relationship with hepatic tissue regeneration 24 hours after PH. Additionally, we analyzed liver regeneration in RL after 70% partial hepatectomy under hypothermic conditions with laser irradiation. Methods: Fifty-six Wistar rats were divided into four groups: total non-perfused liver (control), total perfused liver, partial hepatectomy “in situ”, and partial hepatectomy “ex situ”. Tissue analysis was performed at 0 and 24 hours using spectroscopy with laser devices emitting at 532 (green) and 405 nm (violet). Results: Spectroscopy identified tissue viability based on consistent results with Ki67 staining. The fluorescence spectra and Ki67 analysis displayed similar patterns, linking proliferative activity and absorption intensity. Conclusions: Fluorescence spectroscopy proves to be promising for real-time analysis of cellular activity and viability. Metabolic activity was observed in groups of live animals and hypothermically preserved samples, indicating cellular function even under blood deprivation and hypothermic conditions.

PURPOSE: To evaluate which is the best route of administration for cell therapy in experimental rat model of small-for size syndrome. METHODS: A total of 40 rats underwent partial hepatectomy (70%) that induces the small-for-size syndrome and were divided into four groups of route administration: intravenous, intraperitoneal, enteral and tracheal. The small-for-size syndrome model was designed with extended partial hepatectomy (70%). The animals were divided into four groups of routes administration: intravenous (n=10) - intravenously through the dorsal vein of the penis; intraperitoneal (n=10) - intraperitoneally in the abdominal cavity; enteral (n=10) - oroenteral with the placement of a number 4 urethral probe and maintained at third duodenal portion; tracheal (n=10) - after tracheal intubation. We track the animals and monitor them for 21 days; during this follow-up we evaluated the result of cell therapy application tracking animals using ultrasound, radiography and PET-scan. Statistical analysis was performed using GraphPad Prism Software(r). Differences were considered significant with the p<0.05. Data are presented as the median and variation for continuous variables. Comparisons between groups were made using analysis of the imaging test by the researchers. RESULTS: All four groups underwent partial hepatectomy of 70% liver tissue targeting the same weight of resected liver. Initially the PET-scan tests showed similarity in administered cells by different routes. However, in few days the route of intravenous administration showed to be the most appropriated to lead cells to the liver followed by enteral. The tracheal and peritoneal routes were not as much successful for this goal. CONCLUSION: The intravenous route is the best one to cell therapy in experimental rat model of small-for size-syndrome.

PURPOSE:To evaluate surfactant protein A levels in an hepatopulmonary syndrome rat model. To date, there have been no studies aimed at evaluating surfactant levels in the setting of cirrhosis or hepatopulmonary syndrome.METHODS:A total of 35 rats were divided into control, sham, and experimental HPS groups. We evaluated surfactant protein A levels in rats and the experimental model designed to induce hepatopulmonary syndrome was common bile duct ligation. Statistical analysis was performed using GraphPad Prism Software(r). Differences were considered statistically significant when p<0.05.RESULTS:Lung homogenate of surfactant protein A levels were lower in the experimental hepatopulmonary syndrome and sham groups in comparison to the control group (p<0.05). Serum SP-A levels were the same in experimental hepatopulmonary syndrome and control groups but decreased in the sham group compared with the experimental groups (p<0.05). Myeloperoxidase activity was higher in the experimental hepatopulmonary syndrome group than the other two groups (p<0.05).CONCLUSION:Surfactant protein A is present in experimental hepatopulmonary syndrome and leads to an imbalance between serum and pulmonary levels due to systemic inflammatory response.

RACIONAL: A síndrome hepatopulmonar é formada por tríade clínica composta de doença hepática, dilatação vascular intrapulmonar e alterações de gases sanguíneos. Sua patogênese não é bem definida, mas especula-se que uma combinação de fatores, tais como o desequilíbrio das respostas dos receptores de endotelina, remodelação microvascular pulmonar e predisposição genética, leva à translocação bacteriana e dilatação vascular intrapulmonar. OBJETIVO: Avaliar a atividade da mieloperoxidase em modelo experimental de síndrome hepatopulmonar em ratos. MÉTODO: Foram estudados 29 animais divididos em grupos controle, sham e experimental de síndrome hepatopulmonar. O modelo experimental utilizado para induzir a síndrome foi a ligadura de ducto biliar comum. RESULTADOS: Os níveis de mieloperoxidase foram significativamente maiores no grupo ligadura de ducto biliar comum em comparação com os outros grupos. A atividade da mieloperoxidase foi maior no grupo ligadura de ducto biliar comum que o grupo controle (p<0,05) e do grupo sham (p<0,05). CONCLUSÃO: A atividade da mieloperoxidase estava aumentada na síndrome hepatopulmonar experimentais em ratos.

BACKGROUND: Hepatopulmonary syndrome is formed by a triad of liver disease, intrapulmonary vascular dilatation and changes in blood gases. Its pathogenesis is not well defined, but it is speculated that a combination of factors, such as the imbalance of endothelin receptor responses, pulmonary microvascular remodeling, and genetic predisposition, leads to bacterial translocation and intrapulmonary vascular dilatation. AIM: To evaluate the myeloperoxidase activity in hepatopulmonary syndrome in rat model. METHOD: Twenty-nine rats were divided into control, sham and experimental hepatopulmonary syndrome groups. Was evaluated the myeloperoxidase activity and the experimental model used to induce hepatopulmonary syndrome was common bile duct ligation. RESULTS: The myeloperoxidase activity levels were significantly increased in the common bile duct ligation group as compared with the other groups. Myeloperoxidase activity was higher in the common bile duct ligation group than control group (p<0.05) and than sham group (p<0.05). CONCLUSION: The myeloperoxidase activity is increased in experimental hepatopulmonary syndrome in rats.

OBJETIVO: Desenvolver um modelo cirúrgico de IHA e hiperamonemia em ratos, que evita o shunt porto-sistêmico e a ligadura do ducto biliar, que seja aplicável à pesquisa de encefalopatia hepática. MÉTODOS: Após anestesia geral e laparotomia mediana, os pedículos dos lobos laterais direito e caudado foram isolados e clampeados. Após 1 hora, o animal foi reaberto, os clampes retirados e foi realizada hepatectomia anterior subtotal (ressecção dos lobos médio e lateral esquerdo), compreendendo a remoção de 75% do parênquima. Quatro horas após a hepatectomia, amostras de sangue e tecido hepático foram coletadas nos grupos IHA e controle. RESULTADOS: Diferenças entre os grupos IHA e controle foram significativas para ALT, AST, bilirrubina total e direta, sódio, potássio, fosfatase alcalina, gama glutamiltransferase e principalmente amônia. Histologicamente, diferenças significativas foram observadas entre os grupos. CONCLUSÃO: O modelo é útil para o estudo de aspectos específicos da IHA e o desenvolvimento de novas abordagens terapêuticas.

PURPOSE: To develop a reliable surgical model of acute hepatic failure and hyperammonemia in rats that avoids porto-systemic shunt and bile duct ligation, applicable to hepatic encephalopathy research. METHODS: The pedicles of right lateral and caudate lobes were exposed and clamped. One hour later, the animal was reopened, clamps were released and anterior subtotal hepatectomy (resection of median and left lateral lobes) was performed, comprising 75% of liver removal. Four hours after hepatectomy, blood samples and liver tissues were collected from ALF and control groups. RESULTS: Differences between ALF and control groups were significant for ALT, AST, total and direct bilirubin, sodium, potassium, alkaline phosphatasis, gamma-glutamyltransferase and most important, ammonia. Histologically, significant differences were noticed between groups. CONCLUSION: The model is useful for the study of specific aspects of ALF and the development of new therapeutic approaches.

OBJECTIVE: To evaluate the protective effects of N-acetyl cysteine on the pancreas and kidney after pancreatic ischemia reperfusion injury in a rat model. METHODS AND MATERIALS: Pancreatic ischemia reperfusion was performed in Wistar rats for 1 hour. Revascularization was achieved followed by 4 h of reperfusion. A total of 24 animals were divided into four groups: Group 1: sham; Group 2: pancreatic ischemia reperfusion without treatment; Group 3: pancreatic ischemia reperfusion plus N-acetyl cysteine intravenously; and Group 4: pancreatic ischemia reperfusion plus N-acetyl cysteine per os. Blood and tissue samples were collected after reperfusion. RESULTS: There were significant differences in amylase levels between Group 1 (6.11±0.55) and Group 2 (10.30±0.50) [p=0.0002] as well as between Group 2 (10.30±0.50) and Group 4 (7.82±0.38) [p=0.003]; creatinine levels between Group 1 (0.52 ± 0.07) and Group 2 (0.77±0.18) [p=0.035] as well as between Group 2 (0.77±0.18) and Group 3 (0.48±0.13) [p=0.012]; and pancreatic tissue thiobarbituric acid reactive substance levels between Group 1 (1.27±0.96) and Group 2 (2.60±3.01) [p=0.026] as well as between Group 2 (2.60±3.01) and Group 4 (0.52±0.56) [p=0.002]. A decrease in pancreatic tissue GST-α3 gene expression was observed in Group 2 in comparison to Group 1 (p =0.006), and an increase was observed in Groups 3 and 4 when compared to Group 2 (p= 0.025 and p=0.010, respectively). CONCLUSION: This study provides evidence that N-acetyl cysteine has a beneficial effect on pancreatic ischemia reperfusion injury and renal function in a rat model.

OBJETIVO: A lesão de isquemia-reperfusão hepática é um fenômeno presente em eventos tais como ressecções hepáticas e transplante de fígado. A restauração do fluxo sangüíneo após a isquemia gera lesões locais e sistêmicas. Várias técnicas foram desenvolvidas com o objetivo de evitar ou diminuir a lesão de isquemia-reperfusão hepática em situações clínicas. A utilização da reperfusão intermitente após o evento isquêmico (pós-condicionamento) pode alterar a hidrodinâmica e estimular mecanismos endógenos que atenuam o dano da reperfusão. O presente estudo foi realizado para avaliar o potencial efeito protetor do pós-condicionamento em um modelo de isquemia-reperfusão em ratos. MÉTODOS: O pedículo dos lobos mediano e ântero-lateral foi isolado e clampeado por 1 hora. Após 2 horas, o pedículo foi liberado de duas maneiras diferentes: Grupo Controle (n=7): clampe liberado de uma só vez; Grupo Pós-condicionamento (n=7): clampe liberado de maneira intermitente. Malondialdeído (MDA) e expressão do gene GST- α3 foram estudadas nos grupos. RESULTADOS: A peroxidação lipídica foi significativamente diminuída no fígado isquêmico e no fígado não isquêmico pelo pós-condicionamento. A expressão do gene GST- α3 aumentou, porém não significativamente, no grupo pós-condicionamento. CONCLUSÃO: O pós-condicionamento induziu hepatoproteção pela redução da peroxidação lipídica nos fígados isquêmico e não isquêmico.

PURPOSE: Liver ischemia-reperfusion injury is a phenomenon presents in events like liver resections and transplantation. The restoration of blood flow may leads to local and systemic injury. Several techniques have been developed in order to avoid or ameliorate ischemia-reperfusion injury in clinical situations. The application of a sttuter reperfusion after the ischemic event (postconditioning) could alters the hydrodynamics and stimulates endogenous mechanisms that attenuate the reperfusion injury. The present study was designed to evaluate the potential protective effect of postconditioning in a model of ischemia-reperfusion in rats. METHODS: Hepatic anterior pedicle of median and left anterolateral segments were exposed and clamped for 1 hour. Two hours later, clamp was released in two different ways: Control Group (n=7): clamp was release straightforward; Postconditioning Group (n=7): clamp was released intermittently. Lipid peroxidation (malondialdehyde) and expression of the glutathione-s-transferase-α-3 gene were studied. RESULTS: Lipid peroxidation was significantly decreased in ischemic and non-ischemic liver by postconditioning. GST- α3 gene was overexpressed in postconditioned group, but not significantly. CONCLUSION: Postconditioning induced hepatoprotection by reducing lipid peroxidation in the ischemic and non-ischemic liver.

Muitos dos oncogenes detectados em neoplasias malignas humanas pertencem à família do gene ras. Mutações nos códons 12, 13 ou 61 em um dos tres genes ras; H-ras, K-ras e N-ras, convertem esses genes em oncogenes ativos. Ensaios rápidos para detecção dessas mutações pontuais, tais como a reação em cadeia de polimertização têm sido desenvolvidos nas últimas décadas e usados para investigar o papel dos genes ras mutados na patogênese de tumores humanos. As mutações no gene ras podem ser encontradas numa variedade de tipos de tumores. Incidências mais altas aparecem em adenocarcinomas do pâncreas (90%) e cólon (50%). Analisamos 11 amostras de tumores primários de pâncreas com diferentes metástases, três amostras de cistadenoma mucinoso e dois casos de ausência de tumor de material incluído em parafina, de onde extraímos o DNA para realização das amplificações. Os resultados mostraram que todos os casos de tumores apresentaram a banda de 135 pares de bases correspondente ao gene mutado e para os normais, a banda característica de 106 pares de bases. Nos três casos de cistadenoma mucinosos, não detectamos a banda de 135 pares de bases , apenas a banda de 106 pares de bases.

Mutations at codons 12, 13, or 61 of the H-ras, K-ras, and N-ras have been detected in human neoplasias by a variety of techniques. Some of these techniques are very sensitive and can detect K-ras mutation in 90% of the cases of pancreatic adenocarcinomas. We analyzed 11 samples of pancreatic adenocarcinoma, three samples of pancreatic mucinous cystadenoma, and two samples without tumors in formalin-fixed paraffin embedded tissue sections. K-ras mutations at codon 12 were detected by a two-step PCR-enriched technique in all the samples of pancreatic adenocarcinoma, but not in cystadenoma or control samples. This technique may be useful for early detection of pancreatic cancer.