Nano-hydroxyapatite(n-HA) involved in the regeneration of rat nerve injury triggered by overloading stretch

Damage of axon and glial scars formation both inhibit nerve regenerative growth during nerve injury. In addition, mechanical stretch at high displacement rates of 10% tensile strain can cause marked nerve injury, it is important for finding a proper nano biomaterial to repair nerve injury. Nano-hydroxyapatite (n-HA) has excellent biocompatibility and high bioactivity, which is a good candidate for biomedical engineering applications. But the certain mechanism of n-HA on the injured nerve is seldom reported. In this study, we determined the role of n-HA on the mechanical stretch-induced nerve injury at adult rat spine. Mechanical stretch under strain 10% at displacement rates of 60 ​mm/min can cause marked broken vessels and edema in spinal cord and dorsal root ganglion tissue in haematoxylin-eosin (HE) staining. However, n-HA application can reverse hemorrhage and edema triggered by high rates of 60 ​mm/min stretch. Moreover, n-HA can promote positive staining of Netrin-1 increase significantly in spinal cord and dorsal root ganglion tested by immunohistochemistry (IHC) staining. In general, our study indicated that n-HA can repair mechanical stretch-induced nerve injury, it may provide a new approach to block injury and accelerate nerve regeneration in future. •Overloading mechanical stretch can cause marked nerve injury of rat.•n-HA decrease hemorrhage and edema in spinal cord and dorsal root ganglion.•n-HA may activate Netrin-1 expression to promote nerve re-growth in vivo.