Most of the biomaterials used nowadays for the reconstruction of the spinal cord (SC) tissue after an injury, tested in animals, have obtained modest results. This work presents a study about the compatibility of two novel, non-biodegradable, semi-conductive materials, obtained by plasma polymerization: iodine-doped pyrrole (PPy/I) and pyrrole-polyethylene glycol (PPy/PEG). Both polymers, separately, were implanted in the SC tissue of rats after a transection. Prior to implantation, the elemental composition and the physico-chemical properties of polymers were studied by electron scanning microscopy, IR Spectroscopy and thermogravimetric analysis. We used adult female Long Evans rats, subjected to SC transection. Animals were randomized to be allocated in one of the treatment groups and were killed four weeks after the lesion for histology study. Results showed that both implants were integrated to the SC tissue, as inflammatory and gliotic responses, similar to those observed in the control group, and rejection of the implant, were not evident. Moreover, the immediate effect of PPy/I or PPy/PEG in the injured SC prevented secondary tissue destruction, as compared to non-implanted control animals. In conclusion, implants of semi-conductive polymers were well-tolerated and integrated favorably to SC tissue after transection
After a traumatic spinal cord injury (SCI), the damaged tissue initiates a prolonged period of secondary neurodegeneration, which includes the formation of a scar and the subsequent Wallerian degeneration in the chronic phase [1]. Many reports have proposed the use of different materials for repairing the injured spinal cord tissue. Those materials include living tissue, such as stem cells implants [2], olfactory ensheathing glial cells, Schwann cells [3], trophic factors and spinal cord embryonic grafts, with the aim of facilitating the regrowth of spinal cord white matter and restoring its functionality [4]. However, up to now, they have been poorly effective.
