Transcriptional study of the temporal evolution after severe traumatic spinal cord injury (SCI) and neural progenitor cells (NPCs)-transplantation intervention.

The present study is intended to disclose the transcriptional profile of the temporal evolution through the different stages after SCI as well as the molecular processes underlying the NPC based-therapy in order to transcriptionally characterize its therapeutical mechanism. This transcriptional profile analysis of total RNA samples from spinal cord homogenates of adult rats (Sprague Dawley) provides tissular (tought not cell-type specific) information of the critical time points after the injury from 1 to 8 weeks (acute, sub-acute and early-chronic and late-chronic stages) which conferred a wide temporal coverage making it ideal for studying the temporal dynamics of SCI. Furthermore, we have evaluated the impact of intramedullary acute or subacute transplantation of NPCs over the transcriptional regulation of the spinal cord tissue in order to define the functional outcomes of the NPCs therapy. For a better understanding of the molecular mechanisms involved in temporal evolution ocurring after severe traumatic spinal cord injury (SCI), a differential transcriptional profile was evaluated from acute to chronic stages. Severe traumatic contusion was induced by applying 250 kdyn at the T8 thoracic level in adult Sprague Dawley female rats . Spinal cord tissue, including the epicentre of the injury was collected at different time points representing the acute (1 week; T1), subacute (2 weeks; T2), early chronic (4 weeks; T4) and late chronic (8 weeks; T8) phases to perform the transcriptional profiling analysis using Rat Gene Expression microarray platform (Agilent-014879 Whole Rat Genome Microarray 4x44K G4131F, Agilent). Furthermore to evaluate the transcriptional impact of neural progenitor cells (NPC) transplantation in the injured spinal cord, we performed acute and subacute transplantation (right after or 1 week after injury, respectively) to injured rats . Each experimental group consisted in 4 biological replicates, sham uninjured animals (t0) served as a control for injured rats (t1, t2, t4, t8) and 1-week (t1) and 2-weeks (t2) injured animals served as time-matching control of acutely (u1t1) and subacutely (u2t2) transplanted animals, respectively.