Nociceptive stimulation increased caspase 8 mRNA and protein expression
A) Caspase 8 mRNA was unaltered by SCI or SCI+STIM in the acute time points. At 7 days and in the ventral spinal cord at 28 days, caspase 8 mRNA was increased in both SCI and SCI+STIM groups. At 28 days, in the dorsal spinal cord of SCI+STIM subjects, caspase 8 mRNA levels was significantly increased relative to sham controls and SCI. B) Western blot analyses showed that noxious stimulation significantly increased caspase 8 protein levels at 24 hours. At the later time points, dorsal spinal cord levels of caspase 8 were significantly up-regulated in SCI and SCI+STIM subjects compared to shams, while ventral levels were unchanged. [* indicates p < .05 relative to the sham control group, and # indicates p < .05 of the SCI+STIM group relative to the SCI group]. (C) Examples of representative western blot images for caspase 8. β-tubulin served as a loading control protein.