Introduction: Schwann cells establish a molecular milieu permissive toward regeneration of axons. Existing culture techniques require clinically unacceptable mitogenic factors or in vivo predegeneration, and also fail in the culture of Lewis rat Schwann cells. Lewis rats are especially favorable for the study of nerve reconstruction.

Methods: Adult Lewis rat sciatic nerve explants were placed in DMEM+10% FBS to undergo in vitro degeneration. Explants were then dissociated with collagenase and dispase. These “microexplants” were plated with BS media and a variable FBS regimen. Group 1 – 1wk degeneration, BS+10%FBS x4d then BS+2.5%FBS. Group 2 – 1wk degeneration, BS+2.5%FBS. Group 3 – 4wk degeneration, BS+10%FBS x4d then BS+2.5%FBS. Group 4 – 4wk degeneration, BS+2.5%FBS. At near-confluence, cells were subcultured in BS+2.5%FBS. Evaluation was by hemocytometry and immunocytochemistry.

Results: Groups 1 and 2 yielded >2x107 Schwann cells/g nerve, while Groups 3 and 4 yielded >5x107 cells/g nerve, with >85% purity. Yields were obtained by 8 and 12 weeks after initial harvest.

Conclusions: A technique for the successful culture of adult Lewis rat Schwann cells is described. Following a period of in vitro explant degeneration, the use of BS media with reduced levels of fetal bovine serum allows the differential expansion of Schwann cells over fibroblasts.