DNA microarray analysis of the contused spinal cord: Effect of NMDA receptor inhibition

Abstract

Spinal cord injury (SCI)-induced neurodegeneration leads to irreversible and devastating motor and sensory dysfunction. Post-traumatic outcomes are determined by events occurring during the first 24 hours after SCI. An increase in extracellular glutamate concentration to neurotoxic levels is one of the earliest events after SCI. We used Affymetrix DNA oligonucleotide microarrays (with 1,322 DNA probes) analysis to measure gene expression in order to test the hypothesis that SCI-induced N-methyl-D-aspartate (NMDA) receptor activation triggers significant postinjury transcriptional changes. Here we report that SCI, 1 hour after trauma, induced change in mRNA levels of 165 genes and expression sequence tags (ESTs). SCI affected mRNA levels of those genes that regulate predominantly transcription factors, inflammation, cell survival, and membrane excitability. We also report that NMDA receptor inhibition (with -(ϩ)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]-cyclohepten-5,10-imine hydrogen maleate ) reversed the effect of SCI on about 50% of the SCI-affected mRNAs. Especially interesting is the finding that NMDA receptor activation participates in the up-regulation of inflammatory factors. Therefore, SCI-induced NMDA receptor activation is one of the dominant, early signals after trauma that leads to changes in mRNA levels of a number of genes relevant to recovery processes. The majority of MK-801 effects on the SCI-induced mRNA changes reported here are novel. Additionally, we found that the MK-801 treatment also changed the mRNA levels of 168 genes and ESTs that had not been affected by SCI alone, and that some of their gene products could have harmful effects on SCI outcome.

Patterns of Gene Expression Reveal a Temporally Orchestrated Wound Healing Response in the Injured Spinal Cord

“…The pattern of transcript expression was highly orchestrated from 1 to 90 d after injury and consistent in two distinct rat strains. As seen with thoracic contusions (Carmel et al, 2001;Song et al, 2001;Nesic et al, 2002;Tachibana et al, 2002;Di Giovanni et al, 2003;Pan et al, 2004), a profound loss of neural gene expression was observed by 1 d post-SCI. In our longitudinal study, a very modest rebound occurred by 90 d postinjury, reflective of neural tissue loss within the lesion.…”

Gene expression analysis in burn wounds of rats

“…To overcome this caveat we employed fairly rigid standards of present vs. absent conditions in the analyses of the microarray analyses as described in MATERIALS AND METHODS. For the RPA analyses, the lower threshold of sensitivity is in the picogram range, whereas for the microarray analyses, although it is hard to determine based on our experience in a number of paradigms (20), it is more in the nanomolar range.…”

Spinal Cord Injury: A Model of Central Neuropathic Pain

“…Activation of the nuclear factor-B (NF-B) family of transcription factors is an especially signifi cant event considering the fact that NF-B is a critical step in the inducible regulation of over 150 genes involved in infl ammatory, proliferative and cell death responses [41] . A comprehensive analysis of the molecular events following spinal cord injury using DNA microarray analysis has shown that 1 h after trauma there are changes in mRNA levels for 165 genes [42] . In this analysis, SCI affected mRNA levels of genes that regulate transcription factors, infl ammatory processes, cell survival, and membrane excitability.…”