Evaluation of acellular and cellular nerve grafts in repair of rat peripheral nerve.

Nerve grafts composed of basal lamina scaffolds and lacking viable Schwann cells have recently been shown to be effective in supporting axonal regeneration. As only short grafts were used in those studies, the present investigation was conducted to evaluate the ability of long acellular basal lamina nerve grafts and equivalent cellular grafts to support axonal regeneration for nerve gap repair. Cellular grafts consisted of nerve segments that had degenerated in situ for 4 weeks. Acellular grafting material consisted of similar segments that were repeatedly frozen and thawed to kill all cells prior to grafting. The results show that host axons can regenerate through the entire 4-cm length of cellular grafts but not through acellular basal lamina grafts. However, in the acellular grafts numerous axons were seen in the proximal 2-cm region. It is concluded that basal lamina grafts possess limited ability to support axonal regeneration. As in cellular grafts, viable Schwann cells appear to be important for regeneration to occur over longer distances.