Gui-Bo Liu, Yong-Xia Cheng, Yu-Kuan Feng, Chao-Jian Pang, Qi Li, Ying Wang, Hua Jia, Xiao-Jie Tong myelinated fibres (Figure 3 A). The percentages of nerve fibre density and nerve fibre diameter were significantly higher in the experimental group compared to the control group (Table III). These data indicate greater axonal regeneration in ADSC-laden acellular nerve grafts than in non-ADSC-laden grafts. Discussion Cell transplantation has emerged as a novel therapeutic approach for peripheral nerve defects. The ideal transplantable cells should be easily accessible, proliferate in culture and successfully integrate into host tissue with immunological tolerance [20]. Adipose-derived stem cells can be isolated simply by conventional liposuction pro- cedures from abundant subcutaneous fat deposits. Furthermore, these cells can be expanded in culture for extended periods and proliferate rapidly [13, 21]. In the present study, we provided several lines of evidence that ADSC implantation could promote the repair of 10-mm nerve defects in acellular nerve: (i) improved walking behaviour as measured by footprint analysis, (ii) increased conservation of muscle-mass ratio of gastrocnemius and soleus muscles, (iii) increased nerve conduction velocity, and (iv) increased the number of myelinated fibres within the graft. These data indicate that ADSCs have great potential to promote the regeneration of peripheral nerve. However, it is important to note that we only examined the effects of ADSC implantation on the regeneration of peripheral nerve 12 weeks after the grafting, which is one limitation of the present study. Future multiple-time-point and long-term investigations are necessary to find out how long implanted ADSCs can promote the peripheral nerve regeneration and at what time point the ADSCs exhibit the best effects. 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