Dietary anti-oxidant rich oil protect against ischaemia/ reperfusion injury by activation of PKB/Akt and p38 MAPK

Abstract

Background: Red palm oil (RPO) is known as a potent antioxidant rich oil. Previous results have shown that RPO can protect against the consequences of ischaemia/reperfusion. It has been shown that RPO offered protection via the NO-cGMP pathway during ischaemia (Esterhuyse et al., 2006). Hypothesis: RPO may protect against ischaemia/reperfusion injury via the PKB/Akt and MAPK signalling pathways. Methods: Male Wistar rats were fed RPO for 6 weeks. Hearts were excised and mounted on a working rat heart perfusion system. Hearts were exposed to ischaemia for 25 min and reperfused for 20 min. Functional recovery was measured and biochemical analysis was performed in a different set of freeze clamped hearts to determine the degree of kinase phosphorylation. Results: Aortic output recovery was improved (72.1 ± 3.2% in RPO vs. 54.0 ± 3.2% in control, p< 0.05). No changes in activation of PKB/Akt and p38 could be found during ischaemia. The improved functional recovery was associated with an increased phosphorylation of PKB/Akt(Ser473) and p38 during reperfusion. During reperfusion RPO significantly decreased phosphorylation of both JNK54 and JNK46 and attenuated PARP cleavage. Discussion: The results in this study show that dietary RPO supplementation can protect against the consequences of ischaemia/reperfusion. This protection may be caused by the ability of RPO to increase phosphorylation of PKB/Akt and p38 MAPK and dephosphorylation of JNK, which might be associated with inhibition of apoptosis.