Objective To evaluate the efectiveness of using mesenchymal stem cells(MSCs)derived from HUCB(human umbilical cord blood)to a tissue engineered bioartificial nerve on bridging a 1 0 mm sciatic nerve gap.Methods The cord blood mononuclear cells were isolated by lymphocyte separation medium,purified and expanded with MesencultTM medium and acidic environment to produce adherent layer(MSCs).Thirty SD female rats were randomly divided into three groups.Group A:Human amnion tubes were seeded by HUCBMSCs together with fibrin sealant.Group B:Human amnion tubes were seeded only with fibrin sealant.group C:autografts.9 weeks later,a series of examinations were performed which included morphological,sciatic nerve function index,weight of gastrocnemius,histological staining and immunostaining of S100.Results The HUCB-derived mononuclear cells,when seeded in specific medium,gave rise to adherent cells (MSCs).At 9 weeks after the operations,all the examinations of group A was better than group B(P＜0.05).Conclusion HUCBMSCs can be isolated,purified, cultivated and expanded Mesencult~(TM) medium.HUCBMSCs can promote the nerve to regenerate in reparing the sciatic nerve gap.