燃煤型砷中毒患者遗传损伤及癌变机理

Study on mechanism of carcinogenic effect and genetic damage of arsenism caused by burning coal pollution

目的 从遗传损害、癌基因和抑癌基因蛋白异常表达、细胞增殖和凋亡等方面对燃煤型砷中毒患者遗传损伤及癌变机理进行研究并寻找早期及灵敏的分子标记物。方法 综合应用生物化学、分子遗传学、分子病理学和毒理学方法进行实验室检查。结果 患者遗传损害、DNA合成与修复、DNA损伤等指标均发生异常改变 ,与正常人群比较差异均有统计学意义 ;皮肤组织中癌基因、抑癌基因表达异常 ,细胞增殖与凋亡紊乱 ,各指标在组间比较均有不同程度的差异并有统计学意义。结论 1砷致遗传物质发生异常改变以及影响 DNA合成和修复 ,引起癌基因、抑癌基因蛋白的异常表达 ,细胞增殖与凋亡之间的正常比例发生改变 ,机体的自稳机制受到破坏 ,导致细胞过度分裂、持续增殖 ,是砷致病尤其引起细胞癌变的重要机理 ;2皮肤过度角化可能是燃煤砷污染致皮肤癌变的先兆 ;P5 3mt、PCNA、P16和 Cyclin D1蛋白的异常表达及 Apoptosis的表达水平改变有望作为燃煤砷污染致皮肤癌变的预警标志 ;3SCE、CA和 MN分析可作为检测细胞遗传学改变的早期生物指标 ;DPC则可作为中晚期严重损伤的标志物 ;SCGE作为一种早期、实用的方法应用于砷接触人群的 DNA损伤监测具有实际意义。

Objective In order to take further research on mechanism of carcinogenic effect and genetic damage of arsenism caused by burning coal pollution,and to find out some early and sensitive molecular markers for malignant changes of the disease,the patients with arsenism were treated as subjects and the genetic damage, oncogene and tumor suppressor, proliferation and apoptosis were studied.Methods Experimental indexes were determined by biochemical,molecular genetic,molecular pathologic and toxicologic methods. Results Genetic damage, DNA synthesis, repair and DNA damage of patients were abnormally changed and over the normal group's (P<0.01). Abnormal expressions of oncogene and tumor suppressor were found in skin tissue. Proportion disturbance of cell proliferation and apoptosis were observed.The difference of these biomarkers among the every group had statistical significance (P<0.05, P<0.01).Conclusions ①Abnormal changed of germ plasm and DNA synthesis and repair, and overexpressions of oncogene and tumor suppressor protein, and cell cycle proteins arouse cell overdivision and hyper-proliferation, and the abnormal proportion of apoptosis and proliferation of cell is key factor of cell carcinogenesis caused by arsenic.②Skin hyperkeratosis may be earlier stage of skin cancer. Loss expression of P16 protein, over-expression of P53 mt ,PCNA?cyclinD1 protein and abnormal expression of apoptosis may be considered as prognostic biomarkers to skin cancer caused by burning coal pollution. ③Sister chromatid exchanges (SCE), chromosomal aberrations (CA) and micronucleus (MN) in the peripheral lymphocytes may be early consult markers in monitoring change of cell genetics. DNA-protein crosslinks (DPC) may be a useful marker of cell damage in meta- and latephase and single cell gel electrophoresis assay (SCGE, or comet assay) can be used as a sensitive,rapid,handy,practical and early-stage monitoring method to detect DNA damage in the population exposed to arsenic.