GEL MATRIX VEHICLES FOR GROWTH-FACTOR APPLICATION IN NERVE GAP INJURIES REPAIRED WITH TUBES - A COMPARISON OF BIOMATRIX, COLLAGEN, AND METHYLCELLULOSE

The repair of nerve gap injuries with tubular nerve guides has been us ed extensively as an in vivo test model in identifying substances whic h may enhance nerve regeneration. The model has also been used clinica l nerve repair. The objective of this study was to compare three diffe rent gel matrix-forming materials as potential vehicles for growth fac tors in this system. The vehicles included a laminin containing extrac ellular matrix preparation (Biomatrix), collagen, and a 2% methylcellu lose gel. The growth factor test substance consisted of a combination of platelet-derived growth factor BE (PDGF-BB) and insulin-like growth factor I (IGF-I). An 8-mm gap in rat sciatic nerve was repaired with a silicone tube containing each of the vehicles alone or with a combin ation of each vehicle plus PDGF-BB and IGF-I. At 4 weeks after injury, the application of the growth factor combination significantly stimul ated axonal regeneration when applied in methylcellulose or collagen, but not in Biomatrix. A similar trend was present between the vehicle control groups. By 8 weeks after injury, nerves repaired with methylce llulose as a vehicle had significantly greater conduction velocity tha n either collagen or Biomatrix. It was concluded that a 2% methylcellu lose gel was the best of the three matrices tested, both in its effect s on nerve regeneration and flexibility of formulation. (C) 1997 Acade mic Press.