Abstract:

Abstract:Objective  To investigate the effects of 125I seed on the growth and programmed cell death of human glioma cell line SHG-44,and clarify the action mechanism of the related genes in this process. Methods SHG-44 glioma cells were cultivated in vitro, and divided into control group and treatment group.The inhibitory effect of 125I on SHG-44 cell proliferation was determined by MTT method. The  morphological changes of SHG-44 cells were examined by  electron microscopy, TUNEL method and Acridine Orange/Ethidium bromide double fluorescent staining. The gene expresion profile was established by using gene chip technique. Results 125I seed had inhibitory effect on  the proliferation of SHG-44 cells cultivated in vitro in a dose and time-dependent manner.The result of MTT showed that the A value of SHG-44 cells treated with 125I seed was significantly decreased with the increasing of radiation dose and prolongation of time.The inhibitory rate of SHG-44 cells after treated with 125I seed for 3 d was 50%,there was significant difference compared with control group(P<0.05). Autophagy was frequently observed under transmission electron microscope in SHG-44　cells.The number of cells at  S phase  was  reduced while the number of cells at  G1 and G2/M phase was increased.Although the apoptosis in SHG-44 cells was increased,but not more than 2%. There were 56 differential expression genes of SHG-44 cells after exposure to 125I including 36  up-regulation genes  and 20   down-regulation genes. Conclusion 125I seed can inhibit the proliferation of SHG-44 glioma cells in a dose-dependent manner by inducing the programmed cell death. There may be non-apoptotic programmed cell death (autophagy) in SHG-44 glioma cell line after induction by 125I at relatively low concentration. These results suggest that the mechanism of 125I-induced proliferation inhibitory effect and apoptosis in SHG-44 cells may be related to the genes of p53 and ATM pathway，C-myc family ,p16 family ,Bcl-2 family，TNF ligand family and TNF receptor family genes.

Key words: astrocytoma, iodine-125;gene chip