Abstract: Objective To investigate the effects of overexpression of Mash-1 gene on functional recovery and neural differentiation of embryonic stem cells in spinal cord injury mice. Methods CE3 cell line with overexpression of Mash-1 gene was generated with murine stem cell virus. Spinal cord injury model was established with forceps compression in 4-week-old KM mice. Normal saline (model group, n= 12), CE3 cells with or without overexpression Mash-1 gene (CE3-Mash-1 and CE3 groups, n=12 respectively) were transplanted into the areas of injury 3 days after injury. They were assessed with the Basso Mouse Scale (BMS) 1, 7, 14, 21, and 28 days after injury. 6 mice from each group were sacrificed 14 and 28 days after injury respectively. The spinal cord area remained were observed with HE stained, and the expression of Oct3/4, nestin, β-tubulin III and glial fibrillary acidic protein (GFAP) were detected with immunofluorescence in the injured spinal cord in the CE3 and CE3-Mash-1 groups. Results The score of BMS significantly improved in CE3 and CE3-Mash-1 groups compared with that of the model group (F>84.471, P<0.05), with the more area of spinal cord remained (F>49.990, P<0.05). There were less Oct3/4 positive cells in the CE3-Mash-1 group than CE3 group (t=5.439, P<0.001), with more nestin (t=-7.536, P<0.001) and β-tubulin III (t=-9.941, P<0.001) positive cells. However, there was no significant difference in GFAP positive cells between CE3-Mash-1 and CE3 groups (t=1.701, P>0.05). Conclusion Overexpression of Mash-1 gene promotes CE3 cells to differentiate into neurons in spinal cord injury mice, and improve the motor function recovery.

Key words: spinal cord injury, embryonic stem cell, gene transfection, Mash-1, neural differentiation, mice