Effects of the Inhalational Anesthetics Halothane and Sevoflurane on an Experimental Model of Hepatic Injury

Hepatic injury after inhalational anesthesia is controversial. Studies have suggested that inhalational agents generate an immune response that can provoke hepatic injury. The objective of this study was to analyze the effects of the inhalational agents halothane and sevoflurane on the liver of rats submitted to hypoxia and reperfusion. Thirty Wistar rats, pretreated with 0.1% phenobarbital for 5 days, with discontinuation of the drug 24 hours before the experiment to cause hepatic injury, were used. Animals were distributed in five groups of six rats each. The control group (C) did not receive any treatment; in the F group, phenobarbital was used to induce hepatic injury; the Hypoxia group was submitted to 14% oxygen (O2); the H group received 1% halothane and 14% O2; and the S group received 2% sevoflurane and 14% O2. Twenty-four hours after exposure to the gases, blood samples were collected to evaluate transaminases (AST and ALT), and liver samples were collected for histological evaluation. Kruskal-Wallis Analysis of Variance and the Newman-Keuls test were used. Enzymatic activity mean values of AST (280.33, for halothane, 181, for sevoflurane) and ALT (235 for halothane, and 48.33, for sevoflurane) did not show significant differences, and all groups showed elevated values. Compared to halothane on optical microscopy, sevoflurane had lower indices of morphologic changes with p=0.045, for steatosis, p=0.0075, for inflammatory infiltrate, and p=0.0074, for necrosis. Compared to the halothane group, sevoflurane did not show injuries of the liver parenchyma on optical microscopy. A lesão hepática pós-anestesia inalatória ainda é controversa. Estudos sugerem que agentes inalatórios geram uma resposta imune que pode provocar lesões hepáticas. O objetivo deste estudo é analisar o efeito dos anestésicos inalatórios halotano e sevoflurano no fígado de ratos submetidos à hipóxia e à reperfusão. Foram utilizados 30 ratos Wistar pré-tratados com fenobarbital 0,1% por cinco dias, com suspensão da medicação 24 horas antes do experimento, a fim de provocar a lesão hepática. Os animais foram distribuídos em cinco grupos com seis ratos cada. O Grupo C foi o de controle, sem qualquer tipo de tratamento; o Grupo F foi aquele no qual se induziu lesão hepática com fenobarbital; o Grupo Hipóxia foi exposto a 14% de oxigênio (O2); o Grupo H recebeu halotano 1% e 14% de O2; e o Grupo S recebeu sevoflurano 2% e 14% de O2. Contadas 24 horas após a exposição dos gases, realiza