The effect of warm liver ischaemia & reperfusion injury on circulating plasma lipid levels & lipolytic enzyme activity in rat & the impact of ischaemic preconditioning

BACKGROUND & OBJECTIVES: Ischaemia/reperfusion (I/R) associated with major liver surgery compromises liver function. Ischaemic preconditioning (IPC) may be effective in minimizing hepatic I/R injury. This study aimed to investigate the impact of liver ischaemic manipulations on lipid metabolism in rat during the process of liver recovery after liver surgery. METHODS: Sixty three male Wistar rats were assigned to three groups: the sham group, the I/R group which underwent warm ischaemia and reperfusion (I/R), and the IPC group. The animals were subdivided in 3 groups [1(st), 3(rd)and 7(th) postoperative day (PO)]. Hepatic lipase (HL) and total lipase (TL) activity and the levels of aspartate and alanine transaminases (AST, ALT), triglycerides, HDL and cholesterol were measured in plasma. RESULTS: There was no significant difference in the activity of HL and TL between the groups. Significant higher levels of HDL (P<0.0001) were observed in the IPC group when compared to the other groups on the 3(rd) PO day. Triglycerides (P<0.0001) and HDL (P=0.003) in the IPC group were higher than the sham group on the 7(th) PO day while HDL was also higher in the I/R group. Significantly higher cholesterol levels were found in the I/R and IPC groups on the 7(th) PO day, which were not observed in the sham group. There was a similar curve for triglycerides in the sham and IPC groups while there were significantly higher levels of triglycerides on day 7 for the I/R group. The levels of HDL in the IPC group were higher on the 3(rd) and 7(th) PO day, compared to day 1. INTERPRETATION & CONCLUSION: Warm ischaemia and I/R injury do not seem to affect lipolytic enzyme activity after the 1(st) PO day despite the effects on plasma lipids. IPC seems to prevent accumulation of triglycerides and cholesterol in plasma.