Essay: Peripheral nerve injuries

Peripheral nerve injuries are common problem of trauma and in those injuries partial or complete loss of nerve function is frequent during surgical reconstruction. Approximately 2.8% nerve injury cases have been reported annually during trauma1. In peripheral nerve system regeneration of injured nerve by implanting of autografts or synthetic conduits can be achieved, when the length of damaged gap is less than 5cm 2. Biomaterial based conduit is best alternate to substitute the peripheral nerve injuries due to the disadvantages of autografts such as, morbidity of donor site, incomplete yield or partial recovery and difference in size3,4. Though commercially available nerve conduits are best for small gaps but not for larger gaps because physical topography or chemical cues are not identical so, cannot recapitulates the hierarchical organization and biological functions of native nerve5. Native nerve is enclosed of an extracellular matrix that is fibrous and porous6,7. Nanofibrous scaffolds fabricated by electrospinning provide suitable environment for cell attachment and proliferation, because of the similar physical dimension as natural ECM8. The orientation of electrospun nanofibers plays an important role in cell growth and related functions 9. Whereas it is also reported that aligned electrospun fibers have demonstrated utility in directing nerve outgrowth as well as inducing morphological changes10,11,12,13. However, electrospinning is best for production of two-dimensional meshes, but incorporation into three-dimensional constructs for nerve regeneration is difficult and limited14. Clinically-available nerve grafts are limited to single-lumen conduit constructed of collagen, poly (glycolic acid), poly (D,L-lactide-co-??-caprolactone), poly(vinyl alcohol), or decellularized extracellular matrix (ECM) and their recovery is not similar to autografts15. Adequate achievements through experiments have been succeeded by nerve autografts and muscle basal lamina 2. It may be due to in part to the confinement of the nerve within the complex multi-channel structure of the basal lamina16. However, researchers have made an effort for various fabrication methods to mimic multichannel structure but fail to succeed same design17.
Recently, Jeffries and Wang have produced the multichannel nerve conduit by using template electrospinning16, although their model fulfills the 3D nature of native nerve but it contains thin layer of circumferential aligned fibers on the top of the guide to hold the tube structure, but practically it’s not suitable because early degradation of upper thin layer of guide will cause the deformation of whole structure. To address above challenges, novel fabrication scheme for multichannel nerve conduit has been proposed, which is very simple and entire conduit is made up of only one type of longitudinal aligned electrospun nanofibers. We believe that our proposed model is more supportive incomparision to other models because nerve conduit containing aligned nanofibers with open porous longitudinal microchannel structures promote cell growth and peripheral nerve regeneration. Further in vitro testing was performed by using Schwann cells, to evaluate the growth rate of cells on present nerve conduit.