Inhibition of reactive oxygen species downregulates the MAPK pathway in rat spinal cord after limb ischemia reperfusion injury.
BACKGROUND
We examined the activity of mitogen-activated protein kinase (MAPK) family members, extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38, in rats pinal cord after hind limb ischemia reperfusion (IR) and analyzed the role of reactive oxygen species (ROS) as mediators of MAPK signaling under these conditions.


METHODS
In experiment 1, hind limb IR rats were treated intraperitoneally with one of following agents at 30 min before reperfusion: allopurinol (4, 40 mg/kg), superoxide dismutase (SOD, 4000 U/kg), N-nitro-l-arginine methyl ester (l-NAME, 10 mg/kg), or SOD (4000 U/kg) + l-NAME (10 mg/kg). In experiment 2, 5,10,15,20-tetrakis (N-methyl-4'-pyridyl) porphyrinato iron (III) (FeTMPyP) was administered intraperitoneally (1, 3, or 10 mg/kg) 30 min before reperfusion. After 3 d reperfusion period, the spinal cord (L4-6) was harvested to investigate MAPK signaling activity.


RESULTS
In experiment 1, p-ERK and p-JNK levels were significantly higher in the IR group than sham group. Administration of allopurinol, SOD, l-NAME, or SOD + l-NAME significantly reduced the IR-induced increase in p-ERK and p-JNK levels. There were no significant differences in p-p38 levels. In experiment 2, FeTMPyP significantly reduced the IR-induced increase in p-ERK and p-JNK levels in a dose-dependent manner.


CONCLUSIONS
Activation of ERK and JNK in the spinal cord was induced by hind limb IR and was not accompanied by p38 activation. IR-induced MAPK phosphorylation was reduced by inhibition of superoxide, nitric oxide, and peroxynitrite, indicating that ROS produced by hind limb IR mediate the activation of these signaling pathways in the spinal cord, potentially affecting distant organs.
Department of Anesthesiology and Pain Medicine, School of Medicine, Kyungpook National University, Daegu, South Korea.
Eun Kyung
EK
Choi
Department of Anesthesiology and Pain Medicine, School of Medicine, Kyungpook National University, Daegu, South Korea.
Jin-Seok
JS
Yeo
Department of Anesthesiology and Pain Medicine, School of Medicine, Kyungpook National University, Daegu, South Korea.
Chan Yoon
CY
Park
Department of Anesthesiology and Pain Medicine, School of Medicine, Kyungpook National University, Daegu, South Korea.
Ho in
Hi
Na
Department of Anesthesiology and Pain Medicine, School of Medicine, Kyungpook National University, Daegu, South Korea.
Jung a
Ja
Lim
Department of Anesthesiology and Pain Medicine, School of Medicine, Kyungpook National University, Daegu, South Korea.
Jeong-Eun
JE
Lee
Department of Anesthesiology and Pain Medicine, School of Medicine, Kyungpook National University, Daegu, South Korea.
Seong Wook
SW
Hong
Department of Anesthesiology and Pain Medicine, School of Medicine, Kyungpook National University, Daegu, South Korea.
Sung-Sik
SS
Park
Department of Anesthesiology and Pain Medicine, School of Medicine, Kyungpook National University, Daegu, South Korea.
Dong Gun
DG
Lim
Department of Anesthesiology and Pain Medicine, School of Medicine, Kyungpook National University, Daegu, South Korea. Electronic address: kwakkh@knu.ac.kr.
Kyung Hwa
KH
Kwak
D000818:Animals; D015536:Down-Regulation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D011897:Random Allocation; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species; D015427:Reperfusion Injury / Q000378:metabolism*; D013116:Spinal Cord / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
D017382:Reactive Oxygen Species; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases
Ischemia-reperfusion injury; MAPK; Reactive oxygen species