六价铬对人B淋巴母细胞细胞周期及相关基因表达的影响

Effects of hexavalent chromium on cell cycle and expression of related genes in human B lymphoblastoid cells

目的研究六价铬对人B淋巴母细胞的细胞周期及其相关基因表达的影响。方法用5μM的重铬酸钾对人B淋巴母细胞进行染毒,24 h后去毒,将细胞置新鲜培养基继续孵育;对照组采用PBS处理。收集24 h、3 d和7 d三个时间点细胞,分别用流式细胞术和实时荧光定量PCR方法检测细胞周期及相关基因m RNA表达。结果暴露组细胞染毒24 h和去毒后3 d时G0/G1期细胞比例分别为(70.33±2.03)%和(52.97±1.26)%,分别高于对照组的(46.90±2.65)%和(46.87±1.85)%(均P<0.01),去毒后7 d时两组G0/G1期细胞比例差异无统计学意义(P>0.05)。染毒24 h后,支链氨基酸转氨酶1(BCAT1)、细胞周期素依赖激酶抑制因子1A(CDKN1A)及染色质许可和DNA复制因子1(CDT1)三个基因的m RNA表达均较对照组升高(P<0.05),去毒后3 d均低于对照组(P<0.01),去毒后7 d与对照组差异均无统计学意义(P>0.05)。结论六价铬可通过调控BCAT1、CDKN1A和CDT1基因的表达影响细胞周期进程。

Objective To investigate the influence of hexavalent chromium exposure on cell cycle and the expression levels of cell cycle related genes in human B lymphoblastoid cells. Methods Human B lymphoblastoid cells were treated with 5 μM potassium dichromate for 24 hours and then incubated in fresh medium. The cells in the control group were treated with phosphate buffer saline. The cell cycle and m RNA expression of related genes after 24 hours, 3 days and 7 days were detected by flow cytometry and real-time fluorescent quantitative polymerase chain reaction. Results The proportion of cells in G0/G1 phase after24 hours and 3 days were higher in the exposure group than in the control group [（70.33±2.03） % vs.（46.90 ±2.65） %;（52.97±1.26） % vs.（46.87±1.85） %;all P〈0.01];there was no significant difference in the proportion of cells in G0/G1 phase between the two groups after 7 days（P〉0.05）. The m RNA expression levels of branched chain amino acid transferase 1（BCAT1）, cyclin-dependent kinases（CDKN1 A） and chromatin licensing and DNA replication factor 1（CDT1） in the exposure group were up-regulated in 24 hours and were down-regulated in 3 days after detoxication（all P〈0.05）;there was no significant difference in m RNA expression levels between the two groups after 7 days（P 〉0.05）. Conclusion Hexavalent chromium exposure could influence the cell cycle by modifying the m RNA expression levels of BCAT1,CDKN1 A and CDT1.