论文部分内容阅读
目的:探讨ATM对电离辐射照射的毛细血管扩张共济失调症(ataxia telangiectasia,AT)患者皮肤的成纤维细胞系AT细胞(ATSBIVA)端粒酶活性的影响。方法:以源于正常人皮肤的成纤维细胞系GM细胞(GM0639)为对照,应用基于PCR的端粒重复扩增技术(telomeric repeat amplification protocal,TRAP)与高效液相色谱(HPLC)技术,定量分析细胞分别经0、1、3、5 Gy 60Coγ射线照射后以及经3 Gy 60Coγ射线照射后继续培养2、24、48、72 h,AT、空载体AT、ATM+-AT和GM细胞的端粒酶活性的变化。结果:未照射时,除GM细胞外,AT、空载体AT、ATM+-AT细胞均呈现较高的端粒酶活性表达,但ATM+-AT细胞的端粒酶活性明显低于AT和空载体AT细胞的端粒酶活性(P<0．01),而后二者无明显差异(P> 0．05);电离辐射照射后,AT、空载体AT、ATM+-AT和GM细胞的端粒酶活性均呈剂量依赖性和时间依赖性增强,且在相同剂量点与时间点,ATM+-AT细胞的端粒酶活性高于GM细胞(P<0．01)(除5 Gy计量点外),但低于AT和空载体AT细胞(P<0．01),而后二者无明显差异(P>0．05)。结论:电离辐射可诱导细胞端粒酶活性表达;并且细胞端粒酶活性水平随剂量与时间的增加而增加;ATM可下调AT细胞端粒酶活性水平。推测端粒酶参与电离辐射诱导DNA损伤的修复。
Objective: To investigate the effect of ATM on telomerase activity of ATT cells (ATSBIVA) in the skin of patients with ataxia telangiectasia (AT) exposed to ionizing radiation. Methods: GM-CSF cells derived from human normal skin (GM0639) were used as control. PCR-based telomeric repeat amplification protocol (TRAP) and high performance liquid chromatography (HPLC) The cells were treated with 0, 1, 3 and 5 Gy of 60Coγ ray and irradiated with 3 Gy of 60Coγ ray respectively for 2, 24, 48, and 72 h after AT, empty vector AT, ATM + -AT and GM cells Changes in enzyme activity. Results: In non-irradiated cells, AT, empty vector AT, ATM + -AT cells showed higher expression of telomerase activity except GM cells, but telomerase activity of ATM + -AT cells was significantly lower than AT and empty vector AT (P <0.01), but there was no significant difference between the two groups (P> 0.05). After exposure to ionizing radiation, the telomerase activity of AT, empty vector AT, ATM + -AT and GM cells The telomerase activity of ATM + -AT cells was higher than that of GM cells at the same dose point and time point (except for 5 Gy measurement points) Which was lower than AT and empty vector AT cells (P <0.01), but there was no significant difference between them (P> 0.05). CONCLUSION: Ionizing radiation can induce the expression of telomerase activity, and telomerase activity increases with dose and time. ATM can down-regulate telomerase activity in AT cells. It is hypothesized that telomerase participates in the repair of DNA damage induced by ionizing radiation.