Real-time quantitative PCR analysis of rat diaphragm before and after acute cervical spinal cord injury

Male Sprague Dawley adult rats were subjected to a cervical hemisection at C2 (C2HS). Costal diaphragm (both ipsilesional and contralesional sides) were assessed under control conditions (sham surgery) and at 1 and 7 days post-C2HS. We used SA Biosciences Rat Skeletal Muscle Development and Disease RT2 Profiler PCR Array to quantitate gene expression of muscle atrophy and regeneration-relevant genes from the uninjured and injured tissues on the indicated sides and at the indicated timepoints post-lesion. qPCR gene expression profiling. Tissue was derived from the costal diaphragm from control animals, and from contralesional and ipsilesional sides at days 1 and 7 post-lesion. RNA was extracted from flash-frozen tissue (TRIzol reagent) and quantitated via spectrophotometry. Equal amount total RNA from each donor was pooled prior to gene expression analysis. N=3 or 4 rats per condition. Four genes in the array study appeared to undergo unphysiologic increases in expression following SCI: Mmp9, Leptin, activin A and alpha actinin. For these genes, expression levels in control tissue were detectable but extremely low, thus fold-increases following SCI are numerically exaggerated. Therefore, we cannot explicitly comment on the physiologic scale of this response