The expression of vascular endothelial growth factor and apoptosis after spinal cord injury

Objective To observe the expression level of vascular endothelial growth factor(VEGF) and cells apoptosis at different time points after rats suffering acute spinal cord injury,further in-depth understanding of the pathological changes after spinal cord injury.Methods Female SD rats,which were randomly divided into control group(A group),spinal cord injury group(B group),with 30 animals in each group.The 60 rats were surgically removed the vertebral lamina of T12 segment to expose the spinal cord.And then in A group,the spinal cord was untouched;in B group,the spinal cord was hit by power of 10 g×6 cm according to the improved Allen′s method to establish rat acute spinal cord injury model,then 5 randomly selected rats were sacrificed at 1,3,5,7,14,28 d after injury,materials were obtained from the injury locations following by immunohistochemical staining(IHC) of cell apoptosis and VEGF,observation and calculation of the VEGF positive cells and the positive apoptosis cells under light microscope.Results Except that a few VEGF expressed around central canal and soft meninges of spinal cord,it seldomly expressed in other locations in sham group;In control group,after spinal cord injury VEGF highly expressed in the injured area and its periphery,which reached the peak at 5 d,decreased after 5 d,obviously expressed at 7,14 d and still expressed at 28 d.The expression of VEGF significantly increased at 1,3,5,7,14,28 d compared to control group,and the difference was significant(P0.05).A little TUNEL labeled positive cells were observed at every time point in sham group,while those cells could be observed obviously after spinal cord injury in the control and intervention groups.Apoptotic cells gradually increased after injury,reached the peak at 1 d,decreased after that.At 5,7 d time points there were still many apoptotic cells and still existed at 14,28 d.The apoptotic cells increased at 1,3,5,7,14,28 d compared to control group,and the difference was significant(P0.05).Conclusions VEGF plays a part in the pathological change after spinal cord injury,and it persists a long time.Secondary neuron apoptosis exist for a long time after SCI.