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Objective To investigate the effect of temozolomide (TMZ) and methylprednisolone (MP) on the radiosensitivity of human glioma cells (U251 cells), and to provide experimental evidence for optimal chemotherapy in malignant glioma. Methods Human U251 cells were used for this experiment, and treated respectively by 5 schemes: group C (control, not irradiated and no TMZ and MP), R (irradiated alone), R + TMZ (irradiated and TMZ), R + MP (irradiated and MP) and R + TMZ + MP (irradiated, TMZ and MP). Sulforhodamine B (SRB) assay was used to calculate the cell viability percentage. The apoptosis rate of U251 cells was determined by flow cytometry. The expression of Bax and Bcl⁃2 protein in the treated cells was detected by Western blotting. Results After treatment, the survival rate in group R + MP was significantly higher than group R, R + TMZ and R + TMZ + MP (P = 0.000, for all). The proliferation rate of group R + TMZ + MP at 24 and 48 h was higher than group R + TMZ (P = 0.000). The detection of apoptosis showed that the apoptosis rate in experimental groups increased obviously (P = 0.000, for all), but not in group C. In cell apoptosis elevated groups, the apoptosis rate of group R + MP increased less than group R, R + TMZ and R + TMZ + MP (P = 0.000, for all). The Bax expression in group R + TMZ and R + TMZ + MP was clearly higher than group C, R and R + MP (P = 0.000, for all). The Bcl⁃2 protein in group R + MP and R + TMZ + MP was expressed significantly higher than group C, R and R + TMZ (P = 0.000, for all). The highest Bax/Bcl⁃2 ratio was in group R + TMZ (P = 0.000), and the lowest Bax/Bcl⁃ 2 ratio was in group R + MP (P = 0.000). Conclusion MP could induce human glioma cells to resist radiation. TMZ could improve the radioresistant induced by MP. During the radiotherapy in malignant glioma, the radiation resistant effect induced by using MP to reduce radiotherapeutic adverse reaction could be offset by TMZ. DOI：10.3969/j.issn.1672-6731.2011.03.016 |
