| Spinal cord injury (SCI) is a common disease with a high rate of cripplehood in daily clinical practice of orthopedic. Unfortunately,up to now there is not a valid method to deal with it,all the measures taken in clinical practice result in poor effect,and paraplegia seems ineversible to most of the patients In addition to a primary injury, SCI includes a secondary injury which exacerbates the SCI. The primary injury is the first factor causing SCI, and a secondary injury, including a seriers of pathological and physciological processes, is the final factor deciding the extent of SCI,which may lead to irreversible deprivation of nervous functions.Up to now, the clinical therapeutic effect for SCI is far away from satisfaction, although many experimental therapies have been tried. The reason, in our view, may be attributed to the contradictory between the complexity of SCI and the limitation of the methods or objects taken in our study. The present theories may explored a singal respect of the disease respectively,but cannot give us a whole concept of it. Research of SCI on whole concept put up a higher request of the experiment measures we used. For traditional experimental methods, such as irnmunohistochemistry, Southern blot, Northern blot or RT-PCR, the samples of each experiment are very limited, which cannot meet the need of researches on a large scale. While gene chip, a new tool of scientists rised up in the research of human genome program, brought the hope for the resolve of the problem.Gene chip is a newly developed technique with special advantages. On the base-pairing principle and double-color fluorescent scanning technique, a large amount of specific target gene segments were immobilized onto the substrate of glass or silicon to make gene chip and mRNA or cDNA from two different individuals ( tissue or cell et al) labeled with two colored fluorescence (Cy3 and Cy5) were added to the chip and reacted. Finally, the results were scanned and analyzed with computer and as a result a lot of information about gene expression difference between the two individuals can be obtained. So the gene expression pattern can be obtained and we can further analyse the linkage of the gene expression and the disease. In the present research , We detected the gene expression of injuried spinal cord tissue at different time points with gene chip technique in order to explore the differently expressed genes in injured spinal cord tissue. The present research includes the following parts:1. At first, we made specific gene chip according to standard references, including the following steps: pick up of cDNA clone, probe preparation by PCR amplificaition, printing of probes to the glass slide and post processes.2. We divided 27 healthy adult SD rats,weghing 250~350g, into 3 teams at random: normal,2h after injury,48h after injury, three rats in each team (three repeated experiments) .Then we established model of spinal cord injury according to Nystrom's method.3. At different stipulated time, we take out injuried spinal cord or corresponding section under anesthesia and asepsis and then study the gene expression pattern by gene chip, including the following steps: extraction of RNA, labeling of probes by fluorescence, hybridization and washing of the chip, sanning and computer analysis.The result identified forty-five differentially expressed genes at 2h with elevated expression of 22 genes and reduced expression of 23 genes,and 185 differentially expressed genes at 48h with elevated expression of 35 genes and reduced expression of 150 genes after injury to spinal cord. The differently expressed genes mainly encodes the proteins involed in signaltransduction, protein synthesis and energe metabolism. The results indicate following conclusions:1. Gene chip is a valid method for the study of gene expression pattern of spinal cord..2. Secondary SCI is a complex process with multiple genes.3. More genes were down-regulated after SCI, especially those involved in signal transduction protein sy...
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