Relationship between cell apoptosis and Bcl-2/Bax ratio in neural cells after acute spinal cord injury in rats

AIM: To investigate the expressions of Bcl-2 and Bax and the apoptosis in the neural cells at different time points after acute spinal cord compression injury.METHODS: Twenty-eight rats were divided at random into 2 groups: control group(n=4) and injury group (n=24).The former underwent laminotomy without spinal cord compression,while the latter with spinal cord compression so as to establish the rat models with acute spinal cord injury.The injury group was subdivided randomly into 6 groups,4 in each group.The spinal cord in the injury group was taken at 4 h,8 h,1 d,3 d,7 d and 14 d after injury.The terminal deoxynucleotidal transferasemediated dUTP-biotin nick end labeling(TUNEL) method was used to detect the neural cell apoptosis and immunohistochemical method was used to observe the expressions of Bcl-2 and Bax.The results were analyzed by drawing diagram and statistic methods.RESULTS: TUNEL-positive cells were seen primarily at 4 h after injury,peaked at 8 h and then decreased,but few positive cells still exited at 14 d.The Bcl-2/Bax ratio kept minimal at 8 h and then gradually increased.The lower the Bcl-2/Bax ratio was,the more there were apoptotic cells.CONCLUSION: ① The apoptosis of neural cells and the expressions of bcl-2 and bax occur after the spinal cord injury in rats.② Cell apoptosis is related to the Bcl-2/Bax ratio after acute spinal cord injury in rats.The apoptotic cells are the most when the ratio is the lowest.