Objective:To investigate cytokine changes in cerebrospinal fluid(CSF)of children with mental retardation(MR)before and after neural precursor cell transplantation(NPCT),in an attempt to provide experimental clues for the clinical treatment of MR with NPCT.Methods:The study comprised 28 MR children who received twice NPCT in our hospital.CSF was collected at both NPCT to assess growth factors by ELISA.In addition,the content of insulin-like growth factor 1(IGF-1)in CSF was assayed to determine possible correlations between IGF-1 changes and the short-term therapeutic effect of NPCT.Results:Of all the growth factors detected in CSF,only IGF-1 was increased significantly after NPCT(P<0.05).Fifteen of the twenty-eight MR children achieved short-term therapeutic efficacy,whereby the content of IGF-1 after NPCT was significantly higher than that before NPCT(P<0.05).There was no difference in IGF-1 content in the remaining 13 MR children without short-term therapeutic effect(P=0.657).There was significant difference in IGF-change between the two groups of patients(P<0.05).Conclusion:IGF-1 may be one of the mechanisms contributing to the therapeutic effect of NPCT.