Distraction　osteogenesis　is　widely　used　in　the　treatment　of　bony　deformities　and　defects.　However,　injury　to　the　inferior　alveolar　nerve　is　a　concern.　Our　aim　was　to　investigate　the　feasibility　of　using　lentiviral-mediated　human　nerve　growth　factor　beta　(hNGF　beta)　of　the　inferior　alveolar　nerve　in　mandibular　distraction　osteogenesis　in　rabbits.　To　achieve　this,　mesenchymal　stem　cells　(MSC)　from　the　bone　marrow　of　rabbit　mandibles　were　isolated　and　genetically　engineered　using　recombinant　lentiviral　vector　containing　hNGF　beta.　Twenty　New　Zealand　white　rabbits　underwent　mandibular　distraction　osteogenesis,　and　5　million　MSC　transduced　with　hNGF　beta-vector　or　control　vector　were　transplanted　around　the　nerve　in　the　gap　where　the　bone　had　been　fractured　during　the　operation　(n　=　10　in　each　group).　After　gradual　distraction,　samples　of　the　nerve　were　harvested　for　histological　and　histomorphometric　analysis.　We　found　that　the　genetically　engineered　MSC　transduced　by　the　lentiviral　vector　were　able　to　secrete　hNGF　beta　at　physiologically　relevant　concentrations　as　measured　by　ELISA.　Histological　examination　of　the　nerve　showed　more　regenerating　nerve　fibres　and　less　myelin　debris　in　the　group　in　which　hNGF　beta-modified　MSC　had　been　implanted　than　in　the　control　group.　Histomorphometric　analysis　of　the　nerve　showed　increased　density　of　myelinated　fibres　in　the　group　in　which　hNGF　beta　modified　MSC　had　been　implanted　than　in　the　control　group.　The　data　suggest　that　implantation　of　hNGF　beta-modified　MSC　can　accelerate　the　morphological　recovery　of　the　inferior　alveolar　nerve　during　mandibular　distraction　osteogenesis　in　rabbits.　The　use　of　lentiviral-mediated　gene　treatment　to　deliver　hNGF　beta　through　MSC　may　be　a　promising　way　of　minimising　injury　to　the　nerve.　(C)　2015　The　British　Association　of　Oral　and　Maxillofacial　Surgeons.　Published　by　Elsevier　Ltd.　All　rights　reserved.