Platelet-rich plasma (PRP) is prepared by centrifuging fresh blood in an
anticoagulant state, and harvesting the platelet-rich portion or condensing platelets. Studies have consistently demonstrated that PRP concentrates are an abundant source of
growth factors, such as
platelet-derived growth factor (PDGF),
transforming growth factor β (TGF-β),
insulin-like growth factor 1 (IGF-1), and epithelial
growth factor (
EGF). The complex mechanisms underlying
spinal cord injury (SCI) diminish intrinsic repair and neuronal regeneration. Several studies have suggested that
growth factor-promoted axonal regeneration can occur for an extended period after injury. More importantly, the delivery of exogenous
growth factors contained in PRP, such as
EGF,
IGF-1, and TGF-β, has neurotrophic effects on central nervous system (CNS)
injuries and
neurodegenerative diseases. However, only a few studies have investigated the effects of PRP on CNS
injuries or
neurodegenerative diseases. According to our review of relevant literature, no study has investigated the effect of intrathecal (i.t.) PRP injection into the injured spinal cord and activation of intrinsic mechanisms. In the present study, we directly injected i.t. PRP into rat spinal cords and examined the effects of PRP on normal and injured spinal cords. In rats with normal spinal cords, PRP induced microglia and astrocyte activation and PDGF-B and
ICAM-1 expression. In rats with SCIs, i.t. PRP enhanced the locomotor recovery and spared white matter, promoted angiogenesis and neuronal regeneration, and modulated blood vessel size. Furthermore, a sustained treatment (a bolus of PRP followed by a 1/3 dose of initial PRP concentration) exerted more favorable
therapeutic effects than a single dose of PRP. Our findings suggest by i.t. PRP stimulate angiogenesis, enhancing neuronal regeneration after SCI in rats. Although PRP induces minor
inflammation in normal and injured spinal cords, it has many advantages. It is an autologous, biocompatible, nontoxic material that does not result in a major immune response. In addition, based on its safety and ease of preparation, we hypothesize that PRP is a promising therapeutic agent for SCI.