Functional recovery after repair of peroneal nerve gap using different collagen conduits

Abstract

Currently, autologous nerve implantation to bridge a long nerve gap presents the greatest regenerative performance in spite of substantial drawbacks. In this study, we evaluate the effect of two different collagen conduits bridging a peroneal nerve gap. Rats were divided into four groups: (1) the gold standard group, in which a 10-mm-long nerve segment was cut, reversed, and reimplanted between the nerve stumps; (2) the CG-I/III group, in which a type I/III collagen conduit bridged the gap; (3) the CG-I, in which a type I collagen conduit was grafted; and (4) the sham group, in which a surgery was performed without injuring the nerve. Peroneal Functional Index and kinematics analysis of locomotion were performed weekly during the 12 weeks post-surgery. At the end of the protocol, additional electrophysiological tests, muscular weight measurements, axon counting, and g-ratio analysis were carried out. Functional loss followed by incomplete recovery was observed in animals grafted with collagen conduits. At 12 weeks post-surgery, the ventilatory rate of the CG-I group in response to exercise was similar to the sham group, contrary to the CG-I/III group. After KCl injections, an increase in metabosensitive afferent-fiber activity was recorded, but the response stayed incomplete for the collagen groups compared to the sham group. Furthermore, the CG-I group presented a higher number of axons and seemed to induce a greater axonal maturity compared to the CG-I/III group. Our results suggest that the grafting of a type I collagen conduit may present slight better prospects than a type I/III collagen conduit.