Expression and effect of Caspase-3 in neurons after tractive spinal cord injury in rats.
OBJECTIVE
To investigate Caspase-3 expression and its role in neuronal apoptosis.


METHODS
The T13-L2 spinal cord of rats was injured by traction after the amplitude of P1-N1 wave, monitored by a cortical somatosensory evoked potential (CSEP) monitor, decreased to seventy percent of that before operation. Then rats were killed in 6 h, 1 d, 4 d, 7 d, 14 d and 21 d respectively after operation. Flow cytometer terminal deoxynucleotldyl transferease-mediated biotinylated deoxynuridine triphosphate nick end labeling (TUNEL), Caspase-3 activity assay and immunohistochemical method were applied to investigate Caspase-3 expression in the spinal cord tissue and to study neuronal apoptosis in rats.


RESULTS
After spinal cord injury, apoptotic cells detected by flow cytometry and TUNEL-positive cells were significantly more, and positive immunohistochemical staining of Caspase-3 and Caspase-3 activity were significantly higher in Group injury than in Groups control and laminectomy, respectively (P > 0.05, P > 0.01). Similar trend of changes was noticed in apoptotic cells, TUNEL-positive cells and positive immunohistochemical staining of Caspase-3, all of which reached their respective peak 7 days after operation. Caspase-3 activity reached its peak, however, 4 days postoperatively.


CONCLUSIONS
Increased expression and activity of Caspase-3 protein in neurons after tractive spinal cord injury is the biochemical signal of early spinal cell apoptosis. It is of great significance for understanding the mechanism of spinal cord injury.
Liu
Lei
L
Department of Orthorpaedic Surgery, Southwestern Hospital, Third Military Medical University, Chongqing, China. leilei_0452@sina.com
Pei
Fu-xing
FX
Tang
Kang-lai
KL
Xu
Jian-zhong
JZ
Li
Qi-hong
QH
D000818:Animals; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000032:analysis* / Q000502:physiology; D005434:Flow Cytometry; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000201:enzymology* / Q000473:pathology
C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases