Emilio Elias Abdo1,2, Estela Regina Ramos Figueira1,2, Joel Avancini Rocha-Filho2,3, Eleazar Chaib2,4, Luiz Augusto Carneiro D'Albuquerque2,4, Telesforo Bacchella1,2. 1. Hospital das Clínicas, Universidade de São Paulo, Faculdade de Medicina, Departamento de Gastroenterologia, Divisão de Cirurgia Digestiva, São Paulo, SP, Brasil. 2. Hospital das Clínicas, Universidade de São Paulo, Faculdade de Medicina, Departamento de Gastroenterologia, Laboratório de Investigação Médica LIM37, São Paulo, SP, Brasil. 3. Hospital das Clínicas, Universidade de São Paulo, Faculdade de Medicina, Departamento de Cirurgia, Disciplina de Anestesiologia, São Paulo, SP, Brasil. 4. Hospital das Clínicas, Universidade de São Paulo, Faculdade de Medicina, Departamento de Gastroenterologia, Divisão de Transplante de Fígado e Gastrointestinal, São Paulo, SP, Brasil.
Abstract
BACKGROUND: Ischemia/reperfusion causes organ damage but it is mandatory in hepatic transplantation, trauma and other complex liver surgeries, when Pringle maneuver is applied to minimize bleeding during these procedures. It is well known that liver ischemia/reperfusion leads to microcirculatory disturbance and cellular injury. In this setting hypothermia is known to reduce oxygen demand, lowering intracellular metabolism. OBJECTIVE: : To evaluate the effects of hypothermia in liver ischemia/reperfusion injury, using a new model of topic isolated liver hypothermia. METHODS: We used male Wistar rats weighting about 250 grams, kept in ad libitum feeding regime and randomly divided into two groups of nine animals: 1) Normothermic group, rats were submitted to normothermic ischemia of the median and left hepatic lobes, with subsequent resection of right and caudate lobes during liver reperfusion; and 2) Hypothermic group, rats were submitted to liver ischemia under hypothermia at 10°C. Liver ischemia was performed for 45 minutes. The animals were euthanized 48 hours after liver reperfusion for blood and liver tissue sampling. RESULTS: The transaminases analyses showed a significant decrease of AST and ALT in Hypothermic group (P<0.01) compared to Normothermic group (1403±1234 x 454±213 and 730±680 x 271±211 U/L, respectively). Histology showed severe necrosis in 50% and mild necrosis in 50% of cases in Normothermic group, but severe necrosis in 10% and mild or absent necrosis 90% of the cases in hypothermic group. CONCLUSION: : A simplified model of liver ischemia/reperfusion that simulates orthotopic liver autotransplantion was demonstrated. Topical hypothermia of isolated hepatic lobules showed liver protection, being a viable and practical method for any kind of in vivo liver preservation study.
BACKGROUND:Ischemia/reperfusion causes organ damage but it is mandatory in hepatic transplantation, trauma and other complex liver surgeries, when Pringle maneuver is applied to minimize bleeding during these procedures. It is well known that liver ischemia/reperfusion leads to microcirculatory disturbance and cellular injury. In this setting hypothermia is known to reduce oxygen demand, lowering intracellular metabolism. OBJECTIVE: : To evaluate the effects of hypothermia in liver ischemia/reperfusion injury, using a new model of topic isolated liver hypothermia. METHODS: We used male Wistar rats weighting about 250 grams, kept in ad libitum feeding regime and randomly divided into two groups of nine animals: 1) Normothermic group, rats were submitted to normothermic ischemia of the median and left hepatic lobes, with subsequent resection of right and caudate lobes during liver reperfusion; and 2) Hypothermic group, rats were submitted to liver ischemia under hypothermia at 10°C. Liver ischemia was performed for 45 minutes. The animals were euthanized 48 hours after liver reperfusion for blood and liver tissue sampling. RESULTS: The transaminases analyses showed a significant decrease of AST and ALT in Hypothermic group (P<0.01) compared to Normothermic group (1403±1234 x 454±213 and 730±680 x 271±211 U/L, respectively). Histology showed severe necrosis in 50% and mild necrosis in 50% of cases in Normothermic group, but severe necrosis in 10% and mild or absent necrosis 90% of the cases in hypothermic group. CONCLUSION: : A simplified model of liver ischemia/reperfusion that simulates orthotopic liver autotransplantion was demonstrated. Topical hypothermia of isolated hepatic lobules showed liver protection, being a viable and practical method for any kind of in vivo liver preservation study.