Recombinant human erythropoietin (rhEPO) preconditioning on nuclear factor-kappa B (NF-kB) activation & proinflammatory cytokines induced by myocardial ischaemia-reperfusion.
OBJECTIVE
Erythropoietin (EPO), originally identified for its critical hormonal role in promoting erythrocyte survival and differentiation, has shown to a protective effect in myocardial ischaemia-reperfusion (I-R) injury in animal model. However, the precise mechanisms remain unclear. The objective of this study was to determine the roles of nuclear factor-kappa B (NF-kB) and associated cytokines induced by I-R in the cardioprotection by recombinant human erythropoietin (rhEPO). Morphopathological observations were also made on the ultrastructure of myocardial tissue.


METHODS
Myocardial I-R rat model was established by 30 min ligation of left descending coronary and 3 h reperfusion. RhEPO or saline solution was intraperitoneally injected 24 h before I-R insult. The infarct sizes were measured by triphenyltetrazolium chloride (TTC)-Evans blue technique and ultrastructural organizations were observed by a transmission electron microscope. Tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and IL-10 concentrations were analyzed by enzyme-linked immunosorbance assays and NF-kB by electrophoretic mobility shift assay. TNF-alpha and IL-6 mRNA expression were studied by the reverse-transcription polymerase chain reaction (RT-PCR).


RESULTS
A single bolus injection of 5,000 units/kg of rhEPO 24 h before insult remarkably reduced infarct size and improved ultrastructural organization of I-R myocardium. It greatly suppressed TNF-alpha and IL-6 expression, but enhanced IL-10 production. It modestly activated NF-kB before I-R insult and markedly attenuated subsequent NF-kB activation during sustained I-R.


CONCLUSIONS
The suppression of proinflammatory cytokines expression may act by inhibiting NF-kB activation during I-R, but not by induction of IL-10. This might be one of the molecular mechanisms of rhEPO in cardioprotection. In addition, NF-kB was suggested to play a dual role in cardioprotective effects of rhEPO.
Liu
Xiaoming
X
Department of Anaesthesiology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China.
Shen
Jinchun
J
Jin
Yi
Y
Duan
Manlin
M
Xu
Jianguo
J
D000704:Analysis of Variance; D000818:Animals; D016207:Cytokines / Q000378:metabolism*; D017931:DNA Primers; D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D004921:Erythropoietin / Q000378:metabolism / Q000494:pharmacology*; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D008297:Male; D046529:Microscopy, Electron, Transmission; D015428:Myocardial Reperfusion Injury / Q000378:metabolism*; D009206:Myocardium / Q000648:ultrastructure; D016328:NF-kappa B / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction
D016207:Cytokines; D017931:DNA Primers; D016328:NF-kappa B; D011994:Recombinant Proteins; D004921:Erythropoietin