GDNF–chitosan blended nerve guides: a functional study

Abstract

Nerve guides are currently being fabricated by blending a variety of biomaterials with different proteins. Adding proteins, which can support nerve repair and regeneration, optimizes the biological properties of a nerve guide. In our study we have blended glial cell line-derived nerve growth factor (GDNF) and laminin with chitosan to fabricate GDNF-laminin blended chitosan (GLC) nerve guides. As GDNF is known to provide trophic support to motor neurons, the main objective of this study was assess the functional restoration of an injured sciatic nerve treated with GLC. Functional nerve recovery was evaluated using a video gait-analysis technique. Gastrocnemius muscle weight measurements and sensitivity testing were correlated to functional nerve recovery. Our results indicate an increase in the functional recovery of the GLC group when compared to the unblended chitosan nerve guides. At the end of 12 weeks, GLC nerve guides had comparable functional values to the Laminin-I blended chitosan nerve guides (LC) and autograft groups, which were both significantly higher at the terminal stance phase angle as compared to the unblended chitosan nerve guides. Muscle weights for the GLC group indicated decreased atrophy and restoration of functional strength, compared to the unblended chitosan groups. In addition, behavioural testing demonstrated that the GLC group regained sensation while the control groups displayed no restoration. Thus, the addition of GDNF and laminin to the chitosan nerve guides enhanced both functional and sensory recovery.