Abstract: OBJECTIVE:To investigate protective effects of lycium barbarum polysaccharides (LBP) on radiation-injured spinal cord neurons in vitro. METHODS:SCN cells from spinal cords were cultured in vitro and were injured by exposure to different doses of X-ray irradiation (0,2,6,10 Gy). MTT assay was used to detect cell viability and to determine the best radiation dose. A radiation injury model was established. Irradiated cells were exposed to different concentrations of LBP (15,25,40 mg/L) to detect its protective effects. MTT assay was used to detect the cell survival rate and to determine the optimal dose of LBP intervention. The number of autophagy lysosomes was observed by electron microscope,and expression of the LC3 Ⅱ/I of autophagy-related genes was detected by Western blot and immunohisto-chemistry. RESULTS:Radiation exposure significantly reduced the survival rate of spinal cord nerve cells as shown by data from the MTT assay (P < 0.05). At the concentration of 40 mg/L,Western blot and immunohistochemistry results show that expression of gene LC3 Ⅱ/I was increased in the LBP + radiation group,with statistical significance difference (P < 0.05). CONCLUSION:LBP protected spinal cord neurons from radiation injury in vitro which may be related to its promotion of autophagy-related protein LC3Ⅱ/I expression.

Key words: lycium barbarum polysaccharides, spinal nerve cells, radiation damage, autophagy, LC3 II/I