Recovery of muscle contractile function following nerve gap repair with chemically acellularized peripheral nerve grafts

Acellular nerve grafts have emerged as a possible alternative for reconstruction of short (<2 cm) peripheral nerve gaps. Axonal regeneration has been demonstrated within the nerve constructs. However, very little work has been done to demonstrate both axonal regeneration and recovery of motor function following peripheral nerve gap repair with acellular nerve constructs. The authors hypothesized that chemically acellularized nerve grafts can support axonal regeneration and provide functional reinnervation of rat hindlimb muscles with equivalent efficiency to peripheral nerve autografts. Peroneal nerves were harvested from adult rats and chemically acellularized. Two- and 4-cm peroneal nerve gaps were reconstructed with either a cellular autograft or an acellular isograft. Functional recovery was evaluated with walking-track analyses and measurement of maximum tetanic isometric force (F-0) of the extensor digitorum longus (EDL) muscle. Walking-track analysis revealed no statistically significant difference in functional recovery in rats undergoing reconstruction of 2-cm nerve gaps with acellular isografts or cellular autografts. Maximum tetanic isometric force measurements revealed a 60 percent force deficit in EDL muscles reinnervated by 2-cm acellular nerve grafts, compared to cellular autografts. Four-centimeter acellular grafts failed to support any significant EDL muscle reinnervation. This study demonstrates that chemically acellularized peripheral nerve supports axonal regeneration and functional reinnervation across 2-cm nerve gaps, and may potentially serve as an appropriate scaffold for reintroducing cellular elements, adhesion molecules, or growth factors for repair of longer nerve gaps.