Objective Nogo-A is an axon regeneration inhibitor, and its function in central nervous system （CNS） is still unknown. The present study is to explore the relationship between the expression of Nogo-A and the malignancy of oligodendroglial tumors in patients. Methods Tumor tissue samples with different malignancy grade were obtained from the hospitals. The samples used for detection had been diagnosed as oligodendroglial tumors （oligodendroglioma or anaplastic oligodendroglioma）. The expression of Nogo-A was detected by irmnunohistochemistry and western-blot analysis. The correlation test between the Nogo-A expression and the morphological changes （the percentages of atypical cells and mitotic cells in the tumors） related to the malignancy of tumor tissues was performed. Results There was significant negative correlation between the Nogo-A expression and the morphological change of tumor tissues according to immunohistochemistry. Western-blot analysis also indicated that the gray value of Nogo-A protein band in the oligo- dendroglioma group was significantly higher than that in the anaplastic oligodendroglioma group. Conclusion Nogo-A expression was negatively correlated with the malignancy grade of oligodendroglial tumors.
To study the inhibitory effect of Nogo-A shRNA on cell line PC12, the Nogo-A shRNA （short hairpin RNA, or shRNA） was designed and synthesized. The annealed shRNA template was inserted into plasmid pGenesil-1 containing enhanced green fluorescent protein （EGFP） gene by gene cloning technique to generate eukaryotic expression vector. The recombinant plasmid was transfected into PC12 cells by lipofecamine2000 and the mRNA and protein expression level of Nogo-A gene was detected by RT-PCR and Western blotting 48 h after the transfection. Gene sequencing showed that that the Nogo-A shRNA eukaryotic expression vector was successfully constructed. No significant change was found in the Nogo-A mRNA and protein expression level in empty vector-transfected group as compared with controls （P〉0.05）, while the expression level in shRNA-transfected group decreased significantly （P〈0.05）. It is concluded that the pGenesil-1/Nogo-AshRNA recombinant plasmid can effectively suppress the expression of Nogo-A gene in PC12 cells.
