Dietary red palm oil reduces ischaemia–reperfusion injury in rats fed a hypercholesterolaemic diet
British Journal of Nutrition
We have previously shown that dietary red palm oil (RPO) supplementation improves functional recovery in hearts subjected to ischaemia -reperfusion. However, little knowledge exists concerning the effects of RPO supplementation of a high-cholesterol diet on ischaemia -reperfusion injury. The signalling mechanisms responsible for RPO's effects in the presence of cholesterol also remain to be elucidated. Therefore, the aim of the present study was to examine the effects of RPO, given with a
... given with a high-cholesterol diet, on mitogen-activated protein kinase (MAPK) phosphorylation and apoptosis. Long-Evans rats were fed a control diet, a control diet containing 2 % cholesterol, or a control diet containing 2 % cholesterol and 7 g RPO per kg (CRPO) for 5 weeks. Hearts were excised and mounted on an isolated working heart perfusion apparatus. Cardiac function was measured after which hearts were freeze-clamped and used to assess MAPK phosphorylation and to evaluate apoptosis. Cholesterol supplementation caused a poor aortic output (AO) recovery compared with the control group (35·5 (SEM 6·2) v. 55·4 (SEM 2·5) %), but when RPO was added, the percentage AO increased significantly. The cholesterol group's poor AO was associated with a significant increase in p38-MAPK phosphorylation, whereas the CRPO-supplemented group showed as significant reduction in p38-MAPK phosphorylation when compared with the cholesterol-supplemented group. This significant reduction in p38-MAPK was also associated with reduced apoptosis as indicated by significant reductions in caspase-3 and poly(ADP-ribose) polymerase cleavage. Red palm oil: Mitogen-activated-protein kinase: Ischaemia: Reperfusion * Corresponding author: Dr A.-M. Engelbrecht, fax þ27 21 8083145, email email@example.com Abbreviations: ERK, extracellular signal-regulated protein kinase; JNK, c-Jun NH 2 -terminal kinase; MAPK, mitogen-activated-protein kinase; PARP, poly(ADPribose) polymerase; RPO, red palm oil; Tris, tri(hydroxymethyl)-aminomethane.