Optimization of Schwann cell adhesion in response to shear stress in an in vitro model for peripheral nerve tissue engineering

The design of nerve guidance channels ( NGCs) is evolving to produce a favorable environment for neural regeneration. We created an in vitro model to evaluate the interactions between three centrally important components of this altered host environment: ( 1) Schwann cells, ( 2) substrate, and ( 3) sustained mechanical stimulus in the form of shear stress with laminar fluid flow. Preconfluent Schwann cells were plated on slides coated either with laminin, poly-D-lysine, type IV collagen, or fibronectin. These slides were placed into custom-designed, parallel-plate, flow chambers and were administered laminar fluid flow at a rate of 15 mL/min for 2 h. Schwann cell adhesion assays demonstrated that laminin (mean, 86.1%; SEM, 4.47%) and fibronectin (mean, 81.7%; SEM, 3.24%) were statistically superior to collagen type IV (mean, 57.7%; SEM, 3.96%) and poly-D-lysine ( mean, 58.0%; SEM, 4.97%) (p< 0.001). Fibronectin ( mean, 12.20%; SEM, 0.374%) induced statistically greater Schwann cell proliferation than did laminin ( mean, 8.14%; SEM, 0.682%) (p< 0.001). Therefore, we recommend that fibronectin should be used as an important component of NGCs with further in vivo studies. As mechanical stress is an integral part of the host environment, our study is the first to incorporate this factor into an in vitro model for peripheral nerve tissue engineering.