Mohanty Kuldeep, Dada Rima, Dada Tanuj
a Department of Ophthalmology , Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences , New Delhi , India.
b Department of Anatomy , All India Institute of Medical Sciences , New Delhi , India.
Ophthalmic Genet. 2017 Sep-Oct;38(5):446-450. doi: 10.1080/13816810.2016.1261904. Epub 2017 Jan 27.
Controversy exists regarding the role of oxidative DNA damage and DNA repair in primary open angle glaucoma (POAG). We performed a case control study to test the hypothesis that oxidative DNA damage and base excision repair (BER) genes PARP1 and OGG1 are involved in POAG pathogenesis.
The study included 116 POAG patients and 116 cataract patients as controls. The 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels were measured by ELISA. RNA was extracted from blood by Trizol and converted to cDNA. The relative quantification of PARP1 and OGG1 genes normalized to β-actin was calculated by the 2 method. Comparisons between groups were done by student's t-test and correlation between parameters was seen by Pearson correlation coefficient. All p values less than 0.05 were considered significant.
Mean levels of 8-OHdG were (patients v/s controls) 19.53 ± 1.40 vs. 15.0 ± 2.6 ng/ml in plasma and 8.55 ± 1.94 vs. 5.15 ± 1.09 ng/ml in aqueous humor (p < 0.0001). Expression levels of PARP1 (0.44 ± 0.05 vs. 0.88 ± 0.04) and OGG1 (0.46 ± 0.05 vs. 0.8 ± 0.01) were significantly (p < 0.0001) less in the patients than controls. There was a significant negative correlation between the expression levels of PARP1 and OGG1 with plasma and aqueous 8-OHdG. There was a strong positive correlation between plasma and aqueous 8-OHdG levels.
These results support our hypothesis that oxidative stress-induced DNA damage is associated with POAG. Increased oxidative DNA damage in POAG may be attributed to decreased expression of DNA repair enzymes of the BER pathway.
关于氧化DNA损伤和DNA修复在原发性开角型青光眼（POAG）中的作用存在争议。我们进行了一项病例对照研究，以检验氧化DNA损伤和碱基切除修复（BER）基因PARP1和OGG1参与POAG发病机制的假设。
该研究纳入了116例POAG患者和116例白内障患者作为对照。通过ELISA法检测8-羟基-2'-脱氧鸟苷（8-OHdG）水平。用Trizol从血液中提取RNA并转化为cDNA。以β-肌动蛋白为参照，通过2-△△Ct法计算PARP1和OGG1基因的相对定量。组间比较采用学生t检验，参数间的相关性采用Pearson相关系数分析。所有p值小于0.05被认为具有统计学意义。
血浆中8-OHdG的平均水平（患者与对照组相比）为19.53±1.40 ng/ml对15.0±2.6 ng/ml，房水中为8.55±1.94 ng/ml对5.15±1.09 ng/ml（p<0.0001）。患者中PARP1（0.44±0.05对0.88±0.04）和OGG1（0.46±0.05对0.8±0.01）的表达水平显著低于对照组（p<0.0001）。PARP1和OGG1的表达水平与血浆和房水8-OHdG之间存在显著负相关。血浆和房水8-OHdG水平之间存在强正相关。
这些结果支持我们的假设，即氧化应激诱导的DNA损伤与POAG有关。POAG中氧化DNA损伤增加可能归因于BER途径DNA修复酶表达降低。
