cDNA microarray analysis of spinal cord injury and regeneration related genes in rat

The acute traumatic spinal cord injury (SCI) is a commonly seen and severe case in clinic. However, the repair and regeneration of injured spinal cord is limited. This is likely due to that different kinds of factors are involved in regeneration after SCI. In the present study, we used complementary DNA microarray consisting of 4 041 specific probes from rat to identify genes that were differentially expressed after SCI. The animals were subjected to complete transection injury of the thoracic spinal cord (T8-T9). Sham operated animals received only a laminectomy. Four and a half days later, rat spinal cord was dissected out for total RNA isolation. The fluorescent (Cy3 and Cy5) labeled probes were prepared and hybridized to the microarray. Genes that showed 2-fold difference in SCI tissue were identified. Sixty-five up-regulated genes consisted of 21 known genes, 30 known expressed sequence tags (ESTs) and 14 unknown genes. Seventy-nine down-regulated genes comprised 20 known genes, 42 known ESTs and 17 unknown genes. In 41 differentially expressed known genes, 5 up-regulated genes, i.e., tissue inhibitor of metalloproteinase 1 (Timp1), transgelin (Tagln), vimentin (Vim), Fc gamma receptor, cathepsin S (Ctss), and 3 down-regulated genes, i.e., stearyl-CoA desaturase, coagulation factor II (F2), endosulfin alpha (Ensa), were further confirmed by reverse transcription polymerase chain reaction (RT-PCR). These genes may play a role in the response to tissue damage or repair following SCI and characterization of them might be helpful to elucidate the molecular mechanisms of spinal cord injury and regeneration.