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.