Aim: The presented study is focusing on the effect of increased levels of growth factors (BDNF&GDNF) on the intracellular signaling and regenerative capacity of oligodendrocytes (mature/immature) after thoracic spinal cord injury (SCI).

Methods: Endogenous increase of growth factors (GFs) was induced by 6-weeks endurance training before trauma. The animals were divided into 4 groups: i) control; ii) 6-weeks training; iii) SCI+6-weeks survival; iv) training +SCI+6-weeks survival.

Results: Firstly, we observed that GFs-dependent signaling via PLCγ/PKC and Ras/Erk1/2 pathways is greatly affected by training. Our results pointed out that pre-training significantly increased the gene-expression of PLCγ-PKC and RAS-RAF-MEK-ERK1/2 molecules post-SCI. They play a crucial role in plasticity and regeneration after trauma. Secondly, molecular analysis of mature-oligodendrocytes (PLP1) showed major decrease in the lesion site after SCI, however training significantly (p<0.05) compensated this reduction in gene-expression. Protein analysis confirmed these results and showed that GFs support the oligodendrocytes regeneration. In the adjacent segments, minor loss of PLP protein was detected in both SCI groups. Interestingly, increase of the expression and protein levels for immature-oligodendrocytes-CNPase was visible in training-group (p<0.05) compared to control. Changes were also seen after-SCI, especially at the epicentre of injury, where the levels of CNPase were clearly higher in pre-trained group.

Conclusions: These findings suggest that increased levels of GFs induced by endurance training affect specific signaling-pathways involved in neuroregeneration. We assume that the enhanced regeneration of oligodendrocytes could be caused by increased expression of signaling molecules in Ras-Erk1/2 pathway.