The Mechanisms Of Calcium Mediating IEGs Expression In Spinal Cord Secondary Injury

The secondary injury occurred after spinal cord injury is the primary cause of irreversible paraplegia at present time. The mechanism of the secondary injury is still kept unknown; therefore, we have no methods to impede the processes and to provide effective methods for the therapy of the patients. In the past studies, lots of results indicated that many factors such as oxygen-derived free radicals, ischemia and lipid peroxidation response played an important role in the process of spinal secondary injury. Furthermore, the intercellular calcium ions disequilibrium can lead to the occurrence of all pathophysiological phenomena mentioned above. Much researches has focused on the function of calcium in the spinal secondary injury processes.The present studies of the molecular biology and gene study demonstrated that the secondary injury of the spinal cord is not completely a passive process. To a certain extent, spinal cord secondary injury is thought as a programmed cell death processes, which is controlled by the gene expression strictly. The immediate early genes (EGs) is a adjustable gene proved to take part in pathophysiological processes of the secondary injury in the central nervous system. The EGs genes include c-fos, c-jun, et al, which control the beginning and the end of the central nervous secondary injury through adjusting the target gene. The expressions of IEGs gene is primarily affected by the internal and the external environment, which include calcium ions, calmodulin and calmodulin dependent protein kinase. No study can prove that the function of calcium in the spinal cord secondary process is realized by mediating the expression of the EGs gene. Both NMDA receptor and electric pressure sensible channel are important calcium ionic channels in the central nervous system. The different calcium ionic channel lies in different cell regions, and productsdifferent molecular biology function. If we can confirm that calcium lead the occurrence of spinal cord secondary injury through mediating the expression of EGs gene, the question that calcium channel produces a marked effect in the process is worth to be studied.The past studies confirmed that the calcium ions realize their biological function through acidifying the calmodulin dependent protein kinase, which is mediated by the calmodulin. In order to make sure the pathophysiological process and the molecular biological mechanism of the spinal cord secondary injury, which include the calcium ions internal-flowing, calmodulin activating, protein kinase activation and gene expression. We should make furthermore study to confirm whether it is necessary for CaM and CaM PK in the expression of lEGs gene mediated by the calcium ions. The final goal is to find out the way to impede the pathophysiological process and rescue the patients with spinal cord injury. Consequently, we design and perform the experiments as follows:l.In our experiment, we culture the rat spinal cord slices referring to the technique of the culture of the hippocampal slices and spinal cord slices recommended by Carlline, and modify the technique according to our experiment condition. Then the structure of the cultured spinal cord slices in different time after HE and Nissl stain were observeg. At the same time, we evaluate the activity of the cultured slices with MTT technique. The affection of slice thick was tested and the culture time on the activity of the spinal cord slices and find out the most suitable parameters of the slice culture.2. The cultured spinal cord slices were put into the high calcium ions enviroment and the in vitro model of spinal cord secondary injury was fabricated.3. Study the expression and the changes within the time of the c-fos gene, after the spinal cord slices were treated with high degree calcium ions, the blocker of calcium channel (APS and nicadipine) and the activation (Bayk8644) of calcium channel with in situ hybridization technique. The effections of these factors were studied on the expression of c-fos gene in the spinal cord slices cul...