The Variations And Significance Of Bim's Expression After Acute Spinal Cord Injury In Rats

Objective:To investigate the variations of Bim's expression (Bcl-2 interacting mediator of cell death) between the normal and the acute injured spinal cord cells, research the relationship between the apoptosis and Bim, and explore the characteristics and significance of the expression of Bim and the apoptosis of neurocyte in the temporal distribution after acute spinal cord injury (ASCI).Methods:Rat model of ASCI adopted a modified Allen's method which located in the T8-T10. Sixty-four SD rats used for the experiment, were divided into 8 groups randomly:four groups were performed with ASCI while the rest shamed with false operations. All of the animals were sacrificed at 1h,3h,6h,12h respectively after injury. The neurofunction of spinal cord was evaluated by modified Tarlov score. The changes of morphologic character were observed by using the haematoxylin-eosin (HE) stain. The cell apoptosis was examined by using the TUNEL assay and the expression of Bim was detected by using the immunohistochemistry methods. The expression of Bim and apoptosis were measured by using of IPP (Image-Pro Plus 6.0).The result was demonstrated by IOD (integrated optical density). The observation of apoptosis was measured by using image analysis software IPP6.0, which focused on the apoptotic index= (10 view number of apoptotic cells/ total cells in 10 vision)×100%.Results:The paralyzed rats were not seen in the sham group while the test group was observed with the different severe dysfunction of both lower extremities. The neurofunction of the test group was significantly better than sham group. The Tarlov scores of sham group were higher than the test group (p<0.01). Necrosis and apoptosis cells were not evident in the sham group but could be noted in rats after ASCI. The Bim's expression of test group was higher than the sham group at different times (p<0.01).The increase of Bim began at 1h, peaked at 6h and decreased at 12h(1 h<3h<6h> 12h),(p<0.01). The expression of Bim was related with the apoptosis and the coefficient correlation is positive (p<0.01).Conclusion:The expression of Bim can be induced by acute spinal cord injury (ASCI). The increasing of Bim's expression was related to the apoptosis of neurocyte.