Tao Liu,* Zhongqing Ji,* Shaik Mohammed Ahsan, Yu Zhang, Peng Zhang, Zhihai Fan, Yixin Shen Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou, People’s Republic of China *These authors contributed equally to this work Objectives: To investigate the distribution and function of olfactory ensheathing cells (OECs) following lumbar puncture (LP) transplantation in mouse spinal cord injury (SCI).Methods: OECs were transplanted by LP at level L3–5, 1 week after transected SCI at T8 vertebra. Mice were killed at 3, 21, and 56 days after LP transplantation, and the relative distribution of cells at T8 vertebra was quantitated. The injured spine was also tested by immunohistochemistry to assess neuron regeneration and scar bridging at 8 weeks posttransplantation. Motor functions of mice were evaluated during the observation period using the Basso Mouse Scale.Results: OECs were examined and confirmed by studying cell morphology under phase contrast and immunostaining of NGFR p75. LP-transplanted OECs could be detected just 3 days after transplantation (p75+ area: 0.16 mm2) and accumulated to 0.31 and 0.30 mm2 at 21 and 56 days postengraftment, respectively. The number of endogenous neurons, −400 to +400 µm, far from the epicenter, in OEC-transplanted mice was more than that in SCI mice without engraftment. SCI lesion of mice in the control group (164.3±3.97 µm) was much longer than that in OEC-grafted group (116.7±3.60 µm). Grafts of OECs induced significant functional improvement in mice that underwent T8 vertebral transection, just from 3 days after cell injection.Conclusion: LP is a minimally invasive method for OEC transplantation to treat SCI. This is the first study to visualize the distribution and functions of LP-transplanted OECs in the intact and injured spinal cord. Keywords: olfactory ensheathing cells, spinal cord injury, intrathecal transplantation, lumbar puncture, neuron regeneration, scar bridging