Hypoxia-inducible expression of vascular endothelial growth factor for the treatment of spinal cord injury in a rat model.
OBJECTIVE
Vascular endothelial growth factor (VEGF) has been investigated as a therapy for many disorders and injuries involving ischemia. In this report, we constructed and evaluated a hypoxia-inducible VEGF expression system as a treatment for spinal cord injury (SCI).


METHODS
The hypoxia-inducible VEGF plasmid was constructed using the erythropoietin (Epo) enhancer with the Simian virus 40 (SV40) promoter (pEpo-SV-VEGF) or the RTP801 promoter (pRTP801-VEGF). The expression of VEGF in vitro was evaluated after transfection into N2A cells. The plasmids were then injected into rat spinal cords with contusion injuries. The expression of VEGF in vivo was measured using reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. Locomotor recovery in the rats was evaluated using the Basso, Beattie and Bresnahan (BBB) scale for locomotor analysis.


RESULTS
In vitro transfection showed that pEpo-SV-VEGF or pRTP801-VEGF induced VEGF expression under hypoxic conditions, whereas pSV-VEGF did not. The VEGF level was higher in the pEpo-SV-VEGF and pRTP801-VEGF groups than in the control group. The VEGF expression was detected in neurons and astrocytes of the spinal cord. Locomotor recovery was improved in the pEpo-SV-VEGF and pRTP801-VEGF groups, and BBB scores were higher than in the control group. Staining using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling showed that the number of apoptotic cells decreased in the plasmid-injected groups compared with the control group, and significant differences were observed between the hypoxia-responsive groups and the pSV-VEGF group.


CONCLUSIONS
These results suggest that the hypoxia-inducible VEGF expression system may be useful for gene therapy of SCI.
Choi
Ung Hyune
UH
Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon, Korea.
Ha
Yoon
Y
Huang
Xian
X
Park
So Ra
SR
Chung
Joonho
J
Hyun
Dong Keun
DK
Park
Hyeonseon
H
Park
Hyung Chun
HC
Kim
Sung Wan
SW
Lee
Minhyung
M
D000818:Animals; D017209:Apoptosis; D001253:Astrocytes / Q000378:metabolism; D045744:Cell Line, Tumor; D004742:Enhancer Elements, Genetic; D004921:Erythropoietin / Q000235:genetics; D015870:Gene Expression; D015316:Genetic Therapy; D005822:Genetic Vectors; D000860:Hypoxia / Q000378:metabolism*; D008297:Male; D051379:Mice; D009043:Motor Activity; D009474:Neurons / Q000378:metabolism; D010957:Plasmids; D051381:Rats; D017207:Rats, Sprague-Dawley; D013539:Simian virus 40 / Q000235:genetics; D013116:Spinal Cord / Q000378:metabolism; D013119:Spinal Cord Injuries / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis* / Q000235:genetics / Q000627:therapeutic use*
D042461:Vascular Endothelial Growth Factor A; D004921:Erythropoietin