Mechanism of radiation induced premature senescence of bone marrow stromal cells: experiment with murine bone marrow stromal cells
Zhang, K.-j.; Zhu, Y.; Sun, H.-y.; Huang, L.-f.; Fu, J.-r.; Liu, W.-l.
Zhonghua Yi Xue Za Zhi 86(48): 3431-3434
2006
ISSN/ISBN: 0376-2491 PMID: 17313858 Document Number: 598079
To investigate the mechanism of radiation induced premature senescence of bone marrow stromal cells induced by gamma-radiation. Bone marrow stromal cells were isolated from the bones of mice, cultured, and divided into 2 groups: control group and irradiation group. The cells of the irradiation group were exposed to 60Co gamma-rays of the dose of 8.0 Gy. 24 h, 72 h, 1 week, and 2 weeks after irradiation MTT method was used to test the proliferation of the cells, Giemsa staining was used to observe the morphology, the percentage of cells positive in beta-galactosidase (SA-beta-Gal), a senescence associated biomarker, was detected by cytochemistry, and RT-PCR was used to detect the mRNA expression of p21(Cip1/Waf1) and p53 gene, both associated with senescence. One week after the irradiation flow cytometry was used to analyze the cell cycle distribution. Characteristics of mature senescence were seen in the cells of the irradiation group. One week after the irradiation the percentage of G0/G1 of the irradiation group was 89.83% +/- 0.05%, significantly higher than that of the control group (66.95% +/- 0.36%, P < 0.01). 24 h, 72 h, 1 week, and 2 weeks after irradiation the percentages of SA-beta-gal positive cells in the irradiation group were 20.33% +/- 0.03%, 34.33% +/- 0.03%, 86.33% +/- 0.02%, and 95.67% +/- 0.02% respectively, significantly higher than those of the control group (2.33% +/- 0.006%, 14.33% +/- 0.02%, 24.67% +/- 0.02%, and 45.00% +/- 0.02% respectively, all P < 0.01). The mRNA expression of p53 and p21(Cip1/Waf1) mRNA expressions in the irradiation group increased 24 h after the irradiation and lasted for two weeks. Gamma-radiation induces changes of premature senescence in bone marrow stromal cells in which p53-p21(Cip1/Waf1) manner pathways may play an important role.