Abstract:

The efficacy of platelet rich plasma (PRP) to promote tissue regeneration has been largely confirmed in several clinical setting, such as in human maxillo-facial, heart and orthopaedic surgery. Up to date, few studies are available regarding the topical use of platelet rich plasma in models of peripheral nerve injury or central nervous system pathology and the results contrasting. Farrag et al. (2012) showed positive effects of PRP in a rat model of facial nerve regeneration with a better functional outcome with the use of PRP in comparison with no bioactive agents (platelet-poor plasma). Giannessi et al. (2014) evidenced improvement of the of sciatic nerve regeneration after neurorraphy when a PRP suturable membrane was applied in the lesion site, as showed by electrophysiological parameter showing increase of fiber density. Platelets contain the matrix proteins (fibronectin, vitronectin, and laminin). In a healing wound polypeptide growth factors identified in platelet granule, such as platelet-derived growth factor (PDGF) and transforming growth factor beta (TGFβ), through different signaling pathways, induce transcription, translation, cell division, and/or migration. Fibroblasts are drawn into the fibrin clot by PDGF and TGFβ. The fibroblasts begin to synthesize more fibronectin and also collagen, under the influence of platelet-derived serotonin and TGFβ. In addition, platelets induce cell proliferation and differentiation, stimulate neo angiogenesis and vascular restoring at the site of damage. The bioactive proteins control the nerve healing reducing the scar formation and supporting fiber nerve remyelination by release of large quantities of growth factors fragment, which could polymerize into platelet-rich gel with scaffolding effect.