Location and level of Etk expression in neurons are associated with varied severity of traumatic brain injury.
BACKGROUND
Much recent research effort in traumatic brain injury (TBI) has been devoted to the discovery of a reliable biomarker correlating with severity of injury. Currently, no consensus has been reached regarding a representative marker for traumatic brain injury. In this study, we explored the potential of epithelial/endothelial tyrosine kinase (Etk) as a novel marker for TBI.


RESULTS
TBI was induced in Sprague Dawley (SD) rats by controlled cortical impact. Brain tissue samples were analyzed by Western blot, Q-PCR, and immunofluorescence staining using various markers including glial fibrillary acidic protein, and epithelial/endothelial tyrosine kinase (Etk). Results show increased Etk expression with increased number and severity of impacts. Expression increased 2.36 to 7-fold relative to trauma severity. Significant upregulation of Etk appeared at 1 hour after injury. The expression level of Etk was inversely correlated with distance from injury site. Etk and trauma/inflammation related markers increased post-TBI, while other tyrosine kinases did not.


CONCLUSIONS
The observed correlation between Etk level and the number of impacts, the severity of impact, and the time course after impact, as well as its inverse correlation with distance away from injury site, support the potential of Etk as a possible indicator of trauma severity.
Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China.
John Chung-Che
JC
Wu
Kai-Yun
KY
Chen
Yu-Wen
YW
Yu
Song-Wei
SW
Huang
Hsiu-Ming
HM
Shih
Wen-Ta
WT
Chiu
Yung-Hsiao
YH
Chiang
Chia-Yang
CY
Shiau
D000818:Animals; D001921:Brain / Q000378:metabolism / Q000473:pathology; D001930:Brain Injuries / Q000235:genetics* / Q000378:metabolism; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D009418:S100 Proteins / Q000235:genetics / Q000378:metabolism; D015599:Trauma Severity Indices
D009419:Nerve Tissue Proteins; D009418:S100 Proteins; C492365:Bmx protein, rat; D011505:Protein-Tyrosine Kinases