Bolner A, Pilleri M, De Riva V, Nordera G P
Department of Neurology, Casa di Cura Villa Margherita, Arcugnano, Vicenza, Italy.
Clin Lab. 2011;57(11-12):859-66.
Oxidative stress may be directly or indirectly involved in the pathogenesis of Parkinson's disease (PD). 8-hydroxy-2'deoxyguanosine (8-OHdG) is the major product of DNA oxidative damage but its determination in plasma or urine may have controversial significance. The concentration of 8-OHdG not only depends on its oxidation rate but also on the efficacy of the DNA repairing systems.
We studied the ratio between 8-OHdG and 2-dG (the corresponding not hydroxylated base 2'-deoxyguanosine) in plasma and urine as a marker of oxydative stress in PD. This enabled the determination of the real DNA damage in terms of oxidation rate regardless of the efficacy of the DNA repairing mechanisms.
We optimized two different analytical methods: one for 8-OHdG and the other for 2-dG, both based on a common preliminary solid-phase extraction step (SPE) followed by two different HPLC analytical separations with electrochemical detection (HPLC-ED). The reliability of these methods was confirmed by analysing plasma and urine samples collected in parkinsonian patients and in age-matched healthy control subjects.
In urine samples, the measurement of 8-OHdG alone as well as the ratio 8-OHdG/2-dG were significantly different in healthy controls and PD patients. In plasma samples, only the ratio 8-OHdG/2-dG was significantly higher in PD compared to healthy controls showing that the ratio 8-OHdG/2-dG is a reliable diagnostic tool in studies on DNA oxydative damage.
氧化应激可能直接或间接参与帕金森病（PD）的发病机制。8-羟基-2'-脱氧鸟苷（8-OHdG）是DNA氧化损伤的主要产物，但其在血浆或尿液中的测定可能具有争议性意义。8-OHdG的浓度不仅取决于其氧化速率，还取决于DNA修复系统的功效。
我们研究了血浆和尿液中8-OHdG与2-dG（相应的未羟基化碱基2'-脱氧鸟苷）的比值，作为PD氧化应激的标志物。这能够在不考虑DNA修复机制功效的情况下，根据氧化速率确定实际的DNA损伤。
我们优化了两种不同的分析方法：一种用于8-OHdG，另一种用于2-dG，两者均基于常见的初步固相萃取步骤（SPE），随后进行两种不同的高效液相色谱分析分离并采用电化学检测（HPLC-ED）。通过分析帕金森病患者和年龄匹配的健康对照受试者采集的血浆和尿液样本，证实了这些方法的可靠性。
在尿液样本中，健康对照者和PD患者的8-OHdG单独测量值以及8-OHdG/2-dG比值均有显著差异。在血浆样本中，与健康对照相比，PD患者中仅8-OHdG/2-dG比值显著更高，表明8-OHdG/2-dG比值是DNA氧化损伤研究中的可靠诊断工具。
