EFFECTS OF ANAESTHETIC PRECONDITIONING PLUS POSTCONDITIONING WITH SEVOFLURANE IN WARM LIVER ISCHEMIA/REPERFUSION INJURY IN RATS

Abstract

Background: Preconditioning is a therapeutic strategy aimed to increase ischemic tissue tolerance against ischemia/reperfusion (IR) injury. Recent studies demonstrated that volatile anaesthetics may improve postischemic recovery by an ischemic preconditioning-like mechanism. Postconditioning is a new concept that may have hepatoprotective effect. We hypothesized that sevoflurane preconditioning combined with postconditioning may reduce the hepatocellular damage in a rat model of warm liver IR. Methods: Ten Wistar rats under mechanical ventilation were divided into 2 groups of 5; 1) IR: rats subjected to 45 min of warm liver ischemia of left and median lobes, followed by resection of non-ischemic lobes at early reperfusion; and 2) SEVO + IR: rats were exposed to sevoflurane 2.5% for 15 min, followed by 5 min washout, before ischemia, plus sevoflurane 2.5% for 15 minat reperfusion. Carotid artery was cannulated for mean arterial pressure(MAP). Mean portal flow (MPF) was assessed by perivascular flowprobe. MAP and MPF were recorded at baseline, pre-repefusion and 4 h postreperfusion. Liver transaminases, creatinine, pH, bicarbonate (BIC) and base excess (BE), potassium (K), glucose and lactate were measured at 4 h postreperfusion. Results: AST and ALT were decreased in SEVO + IR group (12.118 ± 3.611 and 7.870 ± 1.586 U/L) compared to IR group (16.890 ± 1.630 and13.418 ± 1.088 U/L), P < 0.05. BIC, and K were increased in SEVO + IR group (11.20 ± .86 mmol/l and 6.1 ± 1.3 mEq/dl) compared to IR (6.70 ± 3.32 mmol/l and 4.7 ± 0.7 mEq/dl),P < 0.05. There were no differ- ences in MAP, MPF, creatinine, glucose, lactate, pH and BE; however glucose tended to be higher in SEVO + IR group (50.8 ± 26.0 mg/dl) compared to IR (35.0 ± 18.4 mg/dl). Conclusions: In experimental warm liver ischemia/reperfusion, sevoflurane preconditioning plus postconditioning reduced the hepatocellular injury demonstrated by lower levels of transaminases with a better behaviour of acid base variables and good hemodynamic recovery. These preliminary results are encouraging because postconditioning may have the advantage of being implemented at the moment of reperfusion, what is more feasible to be applied during liver transplantation surgery.