Objective:To explore the regulatory effect of glutathione S-transferase P1(GSTP1) on the radiosensitivity of mouse Lewis lung cancer (LLC) cells.Methods:GSTP1-shRNA lentivirus and negative control lentivirus were used to respectively infect the LLC cells, and stable transgenic strains were selected. Real-time PCR and Western blot were conducted to quantitatively measure the expression levels of GSTP1 mRNA and protein in the LLC cells to verify the knockdown effect. The cell counting kit-8(CCK-8) assay was used to detect cell viability after irradiation. The colony formation assay was utilized to assess the cell proliferation ability after irradiation. Flow cytometry was performed to assess the level of cell apoptosis after irradiation. The tumor-bearing mice were established and irradiated to detect the changes in the tumor volume after irradiation. TUNEL staining was employed to detect the level of tumor apoptosis after irradiation. Immunofluorescence was used to detect the number of CD 4+ CD 8+ T cells in the tumor after irradiation. Results:Real-time PCR and Western blot showed that after shRNA lentivirus interference, the expression levels of GSTP1 mRNA and protein were significantly down-regulated. Down-regulation of GSTP1 reduced cell viability and proliferation, and increased the rate of cell apoptosis after irradiation. The tumor volume of the tumor-bearing mice after irradiation in the GSTP1 knockdown group was significantly smaller than that in the NC group, whereas the tumor apoptosis rate was significantly higher and the number of infiltrating CD 4+ CD 8+ T cells in the tumor was remarkably higher compared with those in the control group. Conclusion:Knockdown of GSTP1 can significantly increase the radiosensitivity of LLC cells and enhance the infiltration of lymphocytes in tumor tissues.

目的 探讨虾青素对小鼠放射性肺纤维化的防治作用及其机制.方法 60只雌性C57BL/6小鼠随机分为正常组、照射组、照射+虾青素组(25mg/kg),每组20只.除正常组外,其余各组均以60Co γ射线单次16 Gy全胸照射,照射+虾青素组在照射前后每天1次灌胃各7d.照射后1、4、8、16周处死小鼠,取肺组织进行Masson染色,检测肺组织中超氧化物歧化酶(superoxide dismutase,SOD)活性、丙二醛(malondialdehyde,MDA)含量和羟脯氨酸(hydroxyproline,Hyp)含量,测定血清中转化生长因子β1(transforming growth factor-beta 1,TGF-β1)含量.结果 小鼠受照射后肺纤维化严重程度随照后时间延长而加重,用虾青素处理后可明显减轻小鼠肺纤维化严重程度,提高肺组织SOD活力(P＜0.05或P＜0.01)并减少脂质过氧化产物MDA含量(P＜0.05或P＜0.01);抑制小鼠肺组织Hyp和血清中TGF-β1含量的升高(P＜0.05或P＜0.01).结论 虾青素能够有效地减轻放射性肺纤维化,其机制可能与虾青素能够提高机体的抗氧化能力、下调促纤维化因子TGF-β1表达有关.