Preliminary Research On Biological Effect And Its Mechanism In PC12 Cell After Ionizing Radiation

Objective (1) To investigate the biological effect of ionizing radiation(IR) in PC12 cell; (2) To elucidate molecular mechanism of PC12 cell injury induced by IR; (3) To screen new diagnosic biomarkers for central nervous system(CNS) radiation sickness. Methods PC12 cell was irradiated with different dose of ⁶⁰Co y ray. The effect of IR on cell cycle, proliferation, differentiation and death were observed by MTT, flow cytometry, and microscope. Total RNA and total protein of non-irradiated and 16Gy irradiated cells were prepared 48 hours after irradiation. Total RNA was used for oligonucleotide microarray analysis. RT-PCR and quantitative real time-PCR(qRT-PCR) were empolyed to identify the interesting genes. Total protein was analysed by two dimensional gel electrophoresis. Some differentially expressed proteins were characterized by mass spectrometry. Results Irradiated PC12 cell showed proliferation inhibition and cell cycle retardation. Some cells showed differentiation, but some cells died through oncosis. Of the 5705 genes tested, 37 genes were found up-regulated, whereas 3 genes down-regulated in irradiated PC12 cells. Semi-quantitative RT-PCR and qRT-PCR confirmed that mRNA expression levels of 2',5'-oligoadenylate synthetases(OAS1), glucocorticoid-attenuated response genes 16(GARG16) and Interleukin 6(IL-6) increased, whereas mRNA of inhibitor of DNA binding 2(ID2) decreased at 24h and 48h after 16Gy ⁶⁰Co y irradiation. 876 differentially expressed proteins were observed. Ubiquitin carboxyl-terminal hydralase L1(UCH-L1) was found up-regulated. New protein Similar to HP1α was found down-regulated. Conclusion PC12 cell can be used as a nervous injury model after IR. Characterization of some differentially expressed genes and proteins would benefit the research of molecular mechanism of PC12 cell injury induced by IR with oligonucleotide microarray and proteomic analysis. These genes and proteins may involve in cell cycle, proliferation, differentiation and death of PC12 cell.