2011 SSAT POSTER PRESENTATION Ischemic Preconditioning-Like Effect of Polyunsaturated Fatty Acid-Rich Diet on Hepatic Ischemia/Reperfusion Injury Ana Maria Mendonça Coelho & Marcel Cerqueira Cesar Machado & Hilton Kenji Takahashi & Sandra N Sampietre & José Tadeu Stefano & Andre Zonetti A. Leite & Rui Curi & Luiz A. Carneiro D’Albuquerque Received: 25 March 2011 /Accepted: 26 July 2011 /Published online: 9 August 2011 # 2011 The Society for Surgery of the Alimentary Tract Abstract Aim The aim of this study was to investigate a possible preconditioning effect of oral diet enriched with polyunsaturated fatty acids (PUFAs) on liver ischemia/reperfusion (I/R) injuries. Methods Wistar male rats were fed a standard diet or polyunsaturated fatty acid-rich diet (PRD) enriched with (GII) or without (GIII) ω-3 PUFA. Rats were submitted to partial liver ischemia during 1 h and evaluated in pre- and post-I/R conditions. In pre-I/R condition, livers were collected for determination of fatty acid composition, liver mitochondrial function, malondialdehyde (MDA) content, and histological analysis. Four hours after liver reperfusion serum activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), serum levels of tumor necrosis factor-alpha, interleukin-6, interleukin-10, and prostaglandin-E2, liver mitochondrial function, MDA content, and histology were evaluated. Results In the pre-I/R condition, GII and GIII groups had an increase on PUFA content and exhibited slight increased macrosteatosis and microsteatosis in the liver. After 4 h of reperfusion, PRD-fed rats showed a marked decrease on steatosis, diminished necrosis, an increase in MDA formation, and mitochondrial uncoupling. We also observed a marked decrease in plasma levels of cytokines and ALT and AST activities in post-I/R condition in PRD groups. Conclusion In this experimental model in the rat, PRD has a preconditioning effect protecting the liver from I/R injury and should be object of future clinical studies. Keywords Liver ischemic/reperfusion lesion . Preconditioning . Polyunsaturated fatty acid-rich diet . Hepatic mitochondrial dysfunction Introduction Ischemia is a condition caused by partial or absolute blockage of blood flow through an organ, which results in relative deficiency of oxygen supply. Reperfusion and restoration of oxygen supply, paradoxically, aggravate this condition, causing ischemia/reperfusion (I/R) injury. 1–3 Liver I/R injury occurs in several clinical situations such as hemorrhagic shock, hepatic resection, liver transplanta- tion, and in multiple organ failure. Injury in liver arises as a result of multiple pathophysiological processes. 4,5 Oxygen deprivation in liver leads to metabolic imbalance with mitochondrial dysfunction and energy deficiency. Hepato- cyte and endothelial cells swelling after reperfusion contribute to narrowing sinusoidal blood vessels, leukocyte entrapment, and platelet aggregation, resulting in occlusion and failure of hepatic microcirculation. The subsequent inflammatory response with activation of macrophages, This work was presented at the 52nd Annual Meeting of the Society for Surgery of the Alimentary Tract on May 2011, in Chicago, IL. A. M. M. Coelho : M. C. C. Machado (*) : S. N. Sampietre : J. T. Stefano : A. Z. A. Leite : L. A. C. D’Albuquerque Department of Gastroenterology (LIM/37-LIM/07), Medical School, University of Sao Paulo, R. Peixoto Gomide, 515 13 andar, 01409001 Sao Paulo, Sao Paulo, Brazil e-mail: amcoelho@usp.br H. K. Takahashi : R. Curi Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil J Gastrointest Surg (2011) 15:1679–1688 DOI 10.1007/s11605-011-1648-x