Anti-inflammatory effect of erythropoietin pretreatment on cardiomyocytes with hypoxia/reoxygenation injury and the possible mechanism.
OBJECTIVE
To investigate the anti-inflammatory effect of erythropoietin (EPO) pretreatment on cardiomyocytes exposed to hypoxia/reoxygenation injury (H/R) and explore the possible mechanism.


METHODS
The cultured neonatal rats?ventricular cardiomyocytes were divided randomly into 4 groups, control group (C group), EPO pretreatment group (E group), EPO and pyrrolidine dithiocarbamate (PDTC) pretreatment group (EP group) and PDTC pretreatment group (P group). After 24 hours?pretreatment, the cardiomyocytes were exposed to H/R. After pretreatment and H/R, the expression of tumor necrosis factor-alpha(TNF-alpha) gene in all the groups was detected by RT-PCR and Western blot. The nuclear factor-kappa B (NF-kappa B) activity was detected by electrophoretic mobility shift assay (EMSA) and the inhibitor-kappa B alpha (I-kappa B alpha) protein level was detected by Western blot.


RESULTS
The decrement of I-kappa B alpha protein and the increasing NF-kappa B activity were found in cardiomyocytes pretreated with EPO before H/R compared to other groups (t equal to 3.321, 4.183, P less than 0.01). However, after H/R, NF-kappa B activity and expression of TNF-alphagene were significantly reduced, I-kappa B alpha protein expression was increased in cardiomyocytes of E group compared to other groups (t=3.425, 3.687, 3.454, P less than 0.01). All theses changes caused by EPO pretreatment were eliminated by the intervention of PDTC (an antagonist to NF-kappa B) during pretreatment.


CONCLUSIONS
EPO pretreatment can inhibit the activation of NF-kappa B and upregulation of TNF-alpha gene in cardiomyocytes exposed to H/R through a negative feedback of NF-kappa B signaling pathway, and thus produces the anti-inflammatory effect. This might be one of the ways EPO produces the anti-inflammatory effect.
Qin
Chuan
C
Department of Cardiovascular Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
Xiao
Ying-Bin
YB
Zhong
Qian-Jin
QJ
Chen
Lin
L
Wang
Xue-Feng
XF
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D000975:Antioxidants / Q000494:pharmacology; D015153:Blotting, Western; D002478:Cells, Cultured; D024202:Electrophoretic Mobility Shift Assay; D004921:Erythropoietin / Q000494:pharmacology*; D000860:Hypoxia / Q000378:metabolism*; D007249:Inflammation / Q000188:drug therapy; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism; D016328:NF-kappa B / Q000096:biosynthesis; D011759:Pyrrolidines / Q000494:pharmacology; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins; D015427:Reperfusion Injury / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013859:Thiocarbamates / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics
D000975:Antioxidants; D016328:NF-kappa B; D011759:Pyrrolidines; D011994:Recombinant Proteins; D013859:Thiocarbamates; D014409:Tumor Necrosis Factor-alpha; D004921:Erythropoietin; C020972:pyrrolidine dithiocarbamic acid