苯并[a]芘作用下热休克蛋白70表达在染色体损伤和细胞凋亡中作用的研究

HSP70 Expression and its Role in Chromosome Damageand Apoptosis caused by Benzo(a) Pyrene

目的:探讨不同浓度BaP作用不同时间时体外人类肺腺癌细胞热休克蛋白70表达在染色体损伤和细胞凋亡中的作用。方法:用Westernblot和AnnexinV FITCapoptosis凋亡试剂盒以及松胞素B阻断核质分裂微核法分别研究了BaP不同浓度( 0 ,1 2 5 ,2 5 ,5 0 ,10 μmol/L)作用6h体外人类肺腺癌A5 49细胞HSP70的表达、细胞凋亡和染色体的损伤。结果:0～10 μmol/L剂量范围内的BaP作用6h时,肺腺癌细胞HSP70的表达呈不断降低的趋势;细胞凋亡率由7 15±0 0 7%升高到17 3 6±0 2 2 % ,与对照组相比,染毒浓度为5～10 μmol/L时,有统计学意义;细胞微核率由5 77±0 13 %升高到2 1 90±0 89% ,与对照组相比,有统计学意义。结论:低浓度、短时间作用BaP的细胞毒性主要表现为对细胞遗传物质的损伤,细胞凋亡主要在高浓度的BaP诱导下发生。

Objective :To investigate HSP70 expression and its role in chromosome damage and apoptosis caused by benzo(a) pyrene. Methods :The effects of BaP on HSP70 expression and chromosome damage were detected by Western-blot and cytokinesis-blocked micronucleus (CBMN) test respectively and apoptotic cells were assessed by Annexin V-FITC staining and necrotic cells by propidium iodide (PI) staining using flow cytometry on cultured human adenocarcinoma A549 under different concentration (0,1.25,2.5,5.0 and 10μmol/L) BaP.Associations of chromosome damage and apoptosis cell with HSP70 were analyzed in order to elucidate the role of HSP70 expression in chromosome damage and apoptosis caused by BaP. Results :There was a decrease on levels of HSP70 and an increase in chromosome damage and apoptosis in A549 cells treated by 0,1.25,2.5,5.0 and 10μmol/L BaP for 6h ,there was no significant difference( P > 0 .05) of percentage of apoptosis at 0,1.25,2.5μmol/L BaP for 6h,but there was a significant difference( P <0.05) of percentage of chromosone damage at the corresponding concentration of BaP. Conclusion :BaP resulted in the cytotoxicity such as inducing chromosome damage and stimulating apoptosis,but not apoptosis at low concentration of BaP,BaP inhibited HSP70 expression and the induced expression of HSP70 can protect chromosome damage against BaP.