[Differential activation of mitogen-activated protein kinase in PC 12 cells apoptosis induced by electromagnetic irradiation].
OBJECTIVE
To explore the relationship between differential activation of mitogen-activated protein kinase (MAPK) signal transduction system and apoptosis in PC12 cells induced by electromagnetic irradiation.


METHODS
Cultured PC12 cells were exposed to 65 mW/cm(2) electromagnetic wave for 20 min. The PC12 cells apoptosis was detected by flow cytometry 0, 3, 12, 24 h after electromagnetic irradiation. The phosphorylations of ERK1/2, JNK and P38 MAPK were tested by Western-blot.


RESULTS
Electromagnetic irradiation induced apoptosis in PC12 cells soon after irradiation. The apoptotic rate of PC12 cells increased to about 23.5% at 3 h. But compared with that at 3 h, there was no significant difference in the apoptotic rate at 12 h (P > 0.05). The apoptotic rate of PC12 cells increased sharply again at 24 h. After exposure to electromagnetic irradiation, the phosphorylations of ERK1/2 and JNK increased significantly. The increased phosphorylation of ERK1/2 lasted for 3 hours, but of JNK lasted for 12 hours, and 24 hours after irradiation. The phosphorylation of both ERK1/2 and JNK were significantly lower than that of control. The phosphorylation of P38 MAPK was always higher after electromagnetic irradiation, and there were two phosphorylation peaks at 3 h and 24 h.


CONCLUSIONS
The electromagnetic irradiation can induce the activation of MAPK signal transduction system, and ERK1/2, JNK, P38 MAPK showed differential activation. The differential activation of MAPKs may play an important role in the apoptosis of PC12 cells induced by electromagnetic irradiation.
Yang
Xue-sen
XS
Department of Occupation Health, Third Military Medical University, Chongqing 400038, China.
Gong
Qian-fen
QF
Zhang
Guang-bin
GB
Yu
Zheng-ping
ZP
Yu
Xiao-dong
XD
D000818:Animals; D017209:Apoptosis / Q000528:radiation effects*; D015153:Blotting, Western; D005434:Flow Cytometry; D048670:MAP Kinase Kinase 4 / Q000378:metabolism / Q000502:physiology; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism / Q000502:physiology*; D016716:PC12 Cells; D010766:Phosphorylation; D051381:Rats; D015398:Signal Transduction / Q000528:radiation effects*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism / Q000502:physiology
D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4