[Neuroprotective effects of recombinant adeno-associated virus expressing vascular endothelial growth factor on rat traumatic spinal cord injury and its mechanism].
OBJECTIVE
To investigate the neuroprotective effects of recombinant adeno-associated virus (rAAV) expressing vascular endothelial growth factor (VEGF) on traumatic spinal cord injury (SCI) of rat and its mechanisms.


METHODS
The 144 male Sprague Dawley rats were randomly divided into 4 groups, and each group contained 36 rats. The rats in sham group (group A) received dorsal laminectomy without SCI and microinjection, the rats in model control group (group B), rAAV-green fluorescent protein (GFP) group (group C), and rAAV-hVEGF165-GFP group (group D) received dorsal laminectomy with SCI and injection of 20 microL saline, rAAV-GFP viruses, or rAAV-hVEGF165-GFP viruses, respectively. At 3 and 7 days after operation, Basso-Beattie-Bresnahan (BBB) score was used to evaluate the neurologic function. At 7 days after operation, Nissl's body staining was used to evaluate the histopathological changes; apoptosis was confirmed by transmission electron microscope examination and TUNEL staining; the expression of aquaporin 4 (AQP-4) was detected by Western blot assay. At 1, 3, 5, and 7 days, ELISA assay was used to detect the VEGF165 protein expression.


RESULTS
According to BBB scores, the neurologic function in group D was significantly better than those in groups B and C at 3 and 7 days after operation (P < 0.05). Nissl's body staining showed that tissue damage in group D was significantly milder than those in groups B and C at 7 days after operation (P < 0.05). ELISA results showed that VEGF165 protein expression was slowly-released in low dose in group D, and the expression in group D was significantly higher than that in groups A, B, and C at 3, 5, and 7 days after operation (P < 0.05). The results of transmission electron microscope and TUNEL staining showed that apoptosis rate of spinal cord neurons in group D was significantly lower than that in groups B and C at 7 days after operation (P < 0.05). The results of Western blot showed that AQP-4 expression in group D was significantly decreased when compared with that in groups B and C at 7 days after operation (P < 0.05).


CONCLUSIONS
The rAAV expressing VEGF has neuroprotective effects by inhibiting apoptosis of spinal cord neurons and relieving spinal cord edema.
Department of Orthopaedics, Shaanxi Provincial People's Hospital (the Third Affiliated Hospital of School of Medicine, Xi'an Jiaotong University), Xi'an Shaanxi, 710068, P.R.China. qianghui359@163.com
Hui
H
Qiang
Chen
C
Zhang
Zhibin
Z
Shi
Ming
M
Ling
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D051401:Aquaporin 4 / Q000378:metabolism*; D015153:Blotting, Western; D000229:Dependovirus / Q000235:genetics*; D004195:Disease Models, Animal; D005822:Genetic Vectors; D007278:Injections, Spinal; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000378:metabolism / Q000473:pathology; D013119:Spinal Cord Injuries / Q000378:metabolism / Q000628:therapy*; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis* / Q000235:genetics
C496032:Aqp4 protein, rat; D051401:Aquaporin 4; D018696:Neuroprotective Agents; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A