A polylactic acid non-woven nerve conduit for facial nerve regeneration in rats Hajime Matsumine 1,2 * , Ryo Sasaki 2,3 , Masayuki Yamato 2 , Teruo Okano 2 and Hiroyuki Sakurai 4 1 Department of Plastic Surgery, Yachiyo Medical Centre, Tokyo Women’s Medical University, Chiba, Japan 2 Institute of Advanced Biomedical Engineering and Science, Tokyo Women’s Medical University, Japan 3 Department of Oral and Maxillofacial Surgery and Global Centre of Excellence (COE) Programme, Tokyo Women’s Medical University, Japan 4 Department of Plastic Surgery, Tokyo Women’s Medical University, Japan Abstract This study developed a biodegradable nerve conduit with PLA non-woven fabric and evaluated its nerve regeneration-promoting effect. The buccal branch of the facial nerve of 8 week-old Lewis rats was exposed, and a 7 mm nerve defect was created. A nerve conduit made of either PLA non-woven fabric (mean fibre diameter 460 nm), or silicone tube filled with type I collagen gel, or an autologous nerve, was implanted into the nerve defect, and their nerve regenerative abilities were evaluated 13 weeks after the surgery. The number of myelinated neural fibres in the middle portion of the regenerated nerve was the highest for PLA tubes (mean  SD, 5051  2335), followed by autologous nerves (4233  590) and silicone tubes (1604  148). Axon diameter was significantly greater in the PLA tube group (5.17  1.69 mm) than in the silicone tube group (4.25  1.60 mm) and no significant difference was found between the PLA tube and autograft (5.53  1.93 mm) groups. Myelin thickness was greatest for the autograft group (0.65  0.24 mm), followed by the PLA tube (0.54  0.18 mm) and silicone tube (0.38  0.12 mm) groups, showing significant differences among the three groups. The PLA non-woven fabric tube, composed of randomly-connected PLA fibres, is porous and has a number of advantages, such as sufficient strength to maintain luminal structure. The tube has demonstrated a comparable ability to induce peripheral nerve regeneration following autologous nerve transplantation. Copyright © 2012 John Wiley & Sons, Ltd. Received 21 July 2011; Revised 3 March 2012; Accepted 18 April 2012 Keywords regeneration; transplantation; peripheral nerve; tube; nerve guide; polylactic acid 1. Introduction Nerve transplantation is required in various clinical situations, such as fresh trauma (e.g. digital amputation), nerve injury that occurs several months later, and nerve deficit following the removal of a malignant tumour (Rose et al., 1989; Koshima et al., 1997). Autologous nerve transplantation has been conventionally performed for reconstructing 5–10 cm nerve deficits. However, limited nutrient and oxygen supply, associated donor-site morbid- ity and mismatch with the injured nerve can occur (Meek and Coert, 2002). Also, a thick and long nerve graft may develop central necrosis after a few days of ischaemia and thus a satisfactory outcome in such a case cannot be guaranteed (Seddon, 1963). To overcome this problem, vascularized autologous nerve grafts have recently been used and are currently considered the best tissue grafts (Taylor and Ham,1975). However, there are still unavoid- able disadvantages associated with these grafts, including the complexity of the operative procedure, the number of staff required for collecting a nerve graft and prolonged operation time. There are thus great expecta- tions underlying the development of artificial nerves (O’Neill et al., 2009). Biodegradable nerve conduits have been developed from various materials, such as collagen (Alluin et al., 2009), polylactic acid (PLA) (Mligiliche et al., 2003), polyglycolic acid (PGA) (Mackinnon and Dellon, 1990), polylactic-co-glycolic acid (PLGA) (Oh et al., *Correspondence to: H. Matsumine, Department of Plastic Surgery, Yachiyo Medical Centre, Tokyo Women’s Medical University, 477–96 Owada-shinden, Yachiyo-shi, Chiba 276–8524, Japan. E-mail: matsumine@diary.ocn.ne.jp Copyright © 2012 John Wiley & Sons, Ltd. JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE RESEARCH ARTICLE J Tissue Eng Regen Med (2012) Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/term.1540