[The anti-apoptosis effect of erythropoietin on neonatal rat cardiocytes during hypoxia/reoxygenation injury and its possible mechanism].
OBJECTIVE
To investigate the anti-apoptosis effect of erythropoietin (EPO) on myocardial cells after hypoxia/reoxygenation in vitro, and the relationship among protein kinase C (PKC), the mitochondrial ATP-sensitive potassium (mitoKATP) channel and EPO in the anti-apoptotic signaling pathways.


METHODS
Cardiocytes were harvested from neonatal rats and cultured. Cultured myocardial cells were divided into the control group, the hypoxia/reoxygenation group, the EPO group and the chelerythrine group, and a hypoxia/reoxygenation model of cardiocytes was reproduced. Apoptosis rate was assayed by flow cytometry. Flavoprotein fluorescence was scanned by confocal laser microscope to assess the mitoKATP channel activity.


RESULTS
Apoptosis rate was significantly higher in hypoxia/reoxygenation group than that of control group [(42.56+/-8.00)% vs. (17.88+/-2.00)%, P<0.05]. There was no statistically significant difference in flavoprotein fluorescence between this group and the control group [(0.278+/-0.170)x10(-2) vs. (0.149+/-0.050)x10(-2), P>0.05]. Myocardial cell apoptosis rate in EPO group was lower than that in hypoxia/reoxygenation group [(22.73+/-5.00)% vs. (42.56+/-8.00)%, P<0.05], and flavoprotein fluorescence intensity was significantly enhanced when compared with hypoxia/reoxygenation group [(2.201+/-1.090)x10(-2) vs. (0.278+/-0.170)x10(-2), P<0.01]. However, when chelerythrine was added, the anti-apoptosis effect of EPO was blocked, and the intensity of cardiocytes flavoprotein fluorescence was decreased [the apoptosis rate was (46.72+/-17.00)% and the flavoprotein fluorescence intensity was (0.986+/-0.320)x10(-2) ]. When compared with EPO group there was statistically significant difference (P<0.01 and P<0.05).


CONCLUSIONS
Myocardial cell apoptosis occurs in hypoxia/reoxygenation injury, and EPO can protect rat cardiomyocytes from hypoxia/reoxygenation induced apoptosis. The protective effect is partly associated with the PKC/mitoKATP pathway.
Department of Emergency, Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, Guangdong, China.
Hua-jun
HJ
Wang
Hui-lin
HL
Jiang
Xiao-hui
XH
Chen
Pei-yi
PY
Lin
Yong-cheng
YC
Zhu
Li-li
LL
Tao
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015687:Cell Hypoxia / Q000187:drug effects*; D002478:Cells, Cultured; D004921:Erythropoietin / Q000494:pharmacology*; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D015221:Potassium Channels / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects
D015221:Potassium Channels; C117780:mitochondrial K(ATP) channel; D004921:Erythropoietin; D011493:Protein Kinase C