年龄相关性白内障患者外周血淋巴细胞DNA损伤的研究

Quantitative assessment of DNA damage directly in age-related cataract patients

背景年龄相关性白内障是常见的致盲眼病，其病因及发病机制仍是当前的研究热点。研究提示DNA损伤在年龄相关性白内障的发生及发展过程中起重要作用。目的研究外周血淋巴细胞DNA损伤与年龄相关性白内障发生的关系。方法采用横断面研究设计。纳入的年龄相关性白内障患者211例和正常对照组受试者147名均来自“江苏眼病研究：阜宁县2011年眼病流行病调查”人群，两组人群的年龄均为50～80岁，组间性别构成比及年龄均匹配。应用彗星试验检测外周血淋巴细胞尾部DNA含量及Olive尾距（OTM），对两组间测量指标的差异进行比较。将年龄相关性白内障患者分为50～59岁、60～69岁和≥70岁组，对3个组间的外周血淋巴细胞DNA损伤情况进行比较。研究遵循赫尔辛基宣言，经南通大学附属医院伦理委员会批准，所有研究对象均签署知情同意书。采用SPSS17．0统计学软件，对两组人群检测指标的差异进行独立样本t检验，对不同年龄组间检测指标的差异比较采用单因素方差分析。结果彗星试验结果显示，正常对照组受试者外周血淋巴细胞无拖尾现象，而年龄相关性白内障患者的外周血淋巴细胞变大，可见拖尾现象。年龄相关性白内障组患者外周血淋巴细胞尾部DNA百分比和OTM值分别为（21．75±3．51）％和6．54±1．65，均明显高于正常对照组的（9．31±3．60）％和2．18±1．10，差异均有统计学意义（t=32．67，P=0．00；t=28．02，P=0．00）；50—59岁组外周血淋巴细胞尾部DNA含量和OTM值分别为（20．04±2．86）％和5．92±1．14，60～69岁组为（20．77±2．93）％和6．134-1．14，≥70岁组为（22．79±3．67）％和6．95±1．9l，3个组间差异均有统计学意义（F=11．78，P=0．00；F=7．94，P=0．00）。两两比较后发现50～59岁组与≥70岁组、60～69岁组与≥70岁组阃差异均有统计学意义（TailDNA％：q=2．75，P=0．00；q=2．02，P=0．00；OTM：g=1．03，P=0．02；q=0．82，P=0．00）。结论年龄相关性白内障的发生和发展可能与DNA损伤有关。

Background Age-related cataract is one of the common causes of blindness. Although the pathophysiology of age-related cataract is far from clearly understood,it is well accepted that DNA damage plays an important role in the disease pathogenesis. Objective The purpose of this study was to quantitatively evaluate the DNA damage in peripheral lymphoeytes of age-related cataract. Methods A cross-sectional study was carried out. This study complied Declaration of Helsinki and approved by Ethic Committee of Affiliated Hospital of Nantong University. Written informed consent was obtained from each subject. Two hundred and eleven patients with age- related eataract and 147 normal subjects were enrolled from a Jiangsu Eye Study：Funing 2011 Eye Disease Epidemie Survey. All the subjeets aged from 50 through 80 years with matched age and gender between the two groups. The pereentage of tail DNA and Olive tail moment （OTM） were deteeted by eomet assay to assess the extent of DNA damage in peripheral lymphoeytes. Statistical analyses were performed with SPSS 17.0 software,and the differences of the percentage of tail DNA and OTM were compared between the age-related cataract group and normal control group by independent sample t test as well as among the 50-59 years group,60-69 years group and 〉170 years group by one-way analysis of variance. Results Comet assay showed a round lymph cell with the elear border in the normal group;while in the age-related eataraet group,the eell was bigger with a comet-like tail. The percentage of tail DNA and OTM in peripheral lymphocytes were （21.75 ±3.51 ）% and 6.54 ± 1.65 in the age-related cataract group, and those in the normal control group were （ 9.31 ± 3.60 ） % and 2. 18 ± 1. 10, respectively, with significant differences between them （t = 32.67, P= 0.00;t = 28.02,P = 0.00）. In the 50-59 years subgroup of the age-related cataract group ,the percentage of tail DNA and OTM in peripheral lymphocytes were （20.04±2.86）% and 5.92±1. 14 ,and in the 60-69 years subgroup of the age-related cataract group, the percentage of tail DNA and OTM in peripheral lymphocytes were （20. 77-±2.93）% and 6. 13_±1. 14,which were significantly reduced in comparison with （22.79± 3.67）% and 6.95±1.91 of the I〉70 years subgroup（Tail DNA% ：q=2.75,P=0.00; q=2.02,P=0.00;OTM：q= 1.03, P = 0.02 ; q = 0. 82, P=0.00 ）. Conclusions The pathogenesis and development of age-related cataract probably is associated with DNA damage.