title: The effect of dietary red palm oil on the functional recovery of the ischaemic/reperfused isolated rat heart: the involvement of the PI3-kinase signaling pathway.
abstract: We have previously shown that dietary red palm oil (RPO) supplementation improves functional recovery in hearts subjected to ischaemia/reperfusion-induced injury. Unfortunately, the cellular and molecular mechanisms responsible for this phenomenon are still poorly understood and no knowledge exists regarding the effects of RPO supplementation on the phosphoinositide 3-kinase (PI3-K) signaling pathway and apoptosis during ischaemia/reperfusion injury. Therefore, the aims of the present study were three fold: (i) to establish the effect of RPO on the functional recovery of the heart after ischaemia/reperfuion injury; (ii) to determine the effect of the PI3-K pathway in RPO-induced protection with the aid of an inhibitor (wortmannin); and (iii) to evaluate apoptosis in our model. Wistar rats were fed a standard rat chow control diet or a control diet plus 7 g RPO/kg for six weeks. Hearts were excised and mounted on a Langendorff perfusion apparatus. Mechanical function was measured after a 25 min period of total global ischaemia followed by 30 minutes of reperfusion. Hearts subjected to the same conditions were freeze-clamped for biochemical analysis at 10 min during reperfusion to determine the involvement of the PI3-Kinase signaling pathway and apoptosis in our model. Dietary RPO supplementation significantly increased % rate pressure product recovery during reperfusion (71.0 +/- 6.3% in control vs 92.36 +/- 4.489% in RPO; p < 0.05). The % rate pressure product recovery was significantly reduced when wortmannin was added during perfusion (92.36 +/- 4.489% in the RPO group vs 75.21 +/- 5.26% in RPO + Wm). RPO + Wm also significantly attenuated PI3-K induction compared with the RPO group (59.2 +/- 2.8 pixels in RPO vs 37.9 +/- 3.4 pixels in RPO + Wm). We have also demonstrated that PI3-K inhibition induced PARP cleavage (marker of apoptosis) in the hearts during ischaemia/reperfusion injury and that RPO supplementation counteracted this effect.
authors.affiliation: Department of Physiological Sciences, University of Stellenbosch, South Africa. ame@sun.ac.za
authors.forename: Anna-Mart
authors.initials: AM
authors.lastname: Engelbrecht
authors.forename: Louise
authors.initials: L
authors.lastname: Odendaal
authors.forename: Eugene F
authors.initials: EF
authors.lastname: Du Toit
authors.forename: Kristina
authors.initials: K
authors.lastname: Kupai
authors.forename: Tamás
authors.initials: T
authors.lastname: Csont
authors.forename: Peter
authors.initials: P
authors.lastname: Ferdinandy
authors.forename: Jacques
authors.initials: J
authors.lastname: van Rooyen
mesh_terms: D000730:Androstadienes / Q000008:administration & dosage; D000818:Animals; D053148:Caspase 3 / Q000378:metabolism; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology* / Q000627:therapeutic use; D019587:Dietary Supplements; D051858:Forkhead Transcription Factors / Q000378:metabolism; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology*; D066298:In Vitro Techniques; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy / Q000503:physiopathology*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D000073878:Palm Oil; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D010938:Plant Oils / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D020127:Recovery of Function / Q000187:drug effects*; D015398:Signal Transduction / Q000187:drug effects; D000077191:Wortmannin; D000071161:Forkhead Box Protein O1
chemical_list: D000730:Androstadienes; D053148:Caspase 3; D004042:Dietary Fats, Unsaturated; D051858:Forkhead Transcription Factors; D009419:Nerve Tissue Proteins; D000073878:Palm Oil; D019869:Phosphatidylinositol 3-Kinases; D010938:Plant Oils; D011065:Poly(ADP-ribose) Polymerases; D051057:Proto-Oncogene Proteins c-akt; D000077191:Wortmannin; C074639:Foxo1 protein, rat; D000071161:Forkhead Box Protein O1