镉对肾小管上皮细胞中原癌基因c-myc表达的影响

Effects of cadmium on expression of proto-oncogene c-myc in renal tubular epithelial cells

目的探讨镉对肾小管上皮细胞(TEC)毒效应及原癌基因c-myc表达的影响。方法将处于对数生长期的TEC分别暴露于含终浓度为0(对照)、0.625、1.25、2.50、5.0、10.0μmol/L氯化镉的培养基染毒24、48、72 h后,采用MTT法测定TEC的存活情况。将处于对数生长期的TEC分别暴露于含终浓度为0(对照)、0.625、1.25、2.50μmol/L氯化镉的培养基染毒24、48、72 h后,采用RT-qPCR技术检测TEC c-myc mRNA的表达水平。结果与对照组比较,2.50、5.0μmol/L氯化镉染毒24、48、72 h的TEC存活率较高,除5.0μmol/L氯化镉染毒72 h外,差异均有统计学意义(P<0.05)。随着氯化镉染毒剂量的升高,不同染毒时间TEC的存活率均呈先上升后下降的趋势,且均以2.50μmol/L组最高;随着氯化镉染毒时间的延长,2.50、5.0、10.0μmol/L组TEC的存活率均呈下降趋势。与对照组比较,各剂量氯化镉染毒不同时间后TEC中c-myc mRNA的表达水平均较高,差异有统计学意义(P<0.05);且随着氯化镉染毒剂量的升高,不同染毒时间TEC中c-myc mRNA的表达水平均呈上升趋势。结论一定低剂量镉诱导TEC中c-myc持续激活和过表达与镉诱导TEC过度增殖密切相关,可能是镉致肾损伤的毒作用机制之一。

Objective To explore the toxic effects of cadmium on the renal tubular epithelial cell （TEC） and study the effects of cadmium on the expression of proto-oncogene c-mye in TEC. Methods The TEC in logarithmic growth phase were exposed to serum medium containing cadmium chloride at concentrations of 0,0.625,1.25,2.50,5.0, 10.0 μmol/L,respectively. After exposure for 24,48,72 h,MTT method was used to detect the survival of TEC in each group. The TEC in logarithmic growth phase were exposed to serum medium containing cadmium chloride at concentrations of 0,0.625,1.25,2.50 μmol/L, respectively. After exposure for 24,48,72 h, RT-qPCR technique was used to observe mRNA relative expression level of e-mye gene. Results After exposure for 24,48,72 h,survival rates of TEC in 2.50 and 5.0 μmol/L exposure groups were high and showed a significant difference （P〈0.05） compared with the control group, except 2.50 μmol/L exposure group for 72 h.The survival of TEC at different time increased first and then decreased with the increase of exposure dosage, meanwhile,the survival rate in 2.50 μmol/L exposure group were the highest among all groups. As the extension of exposure time, the survival rates of TEC in 2.50, 5.0 and 10.0 μmol/L exposure groups showed a downward trend. Compared with the control group, the expression level of c-myc gene in all exposure groups increased and the difference was significant （P〈0.05）. With the increase of exposure dosage, the expression level of e-myc gene at different exposure time showed an increasing trend. Conclusion The sustained activation and over-expression of c-myc in TEC induced by a certain dosage of cadmium is closely related with proliferation induced by cadmium, which maybe one of the mechanisms of renal damage induced by cadmium.