Contraction of collagen-glycosaminoglycan matrices by peripheral nerve cells in vitro

The objective of this study was to investigate the contractile behavior of peripheral nerve support cells in collagen-glycosaminoglycan (GAG) matrices in vitro. Contractile fibroblasts (myofibroblasts) are known to participate in wound contraction during healing of selected connective tissues (viz., dermis), but little is known about the activity of non-muscle contractile cells during healing of peripheral nerves. Explants from adult rat sciatic nerves were placed onto collagen-GAG matrix disks and maintained in culture for up to 30 days. Groups of collagen-GAG matrices were tested that differed in average pore diameter and in degree of cross-linking. Cell migration from nerve explants into the matrices was examined, and immunohistochemical staining was used to identify cells expressing a contractile actin isoform (alpha-smooth muscle actin; alpha-SMA) and Schwann cells (S-100). Geometric contraction of matrix disks was quantified every five days as the percent reduction in disk diameter. The amount of contraction of matrix disks was significantly affected by the degree of cross-linking. Cell migration into the matrices and the distribution of cells staining for alpha-SMA or S-100 was not affected by matrix parameters. These studies demonstrate that cells from peripheral nerve explants were capable of adopting a contractile phenotype and causing geometric contraction of matrices in vitro and suggest that contractile processes may be important during nerve wound healing in vivo.