Objective The systemic redox imbalance can lead to the occurrence of oxidative stress, which is closely associated with tumor, aging and various diseases. The redox potentials ( Eh) measuring the poise of thiol/disulfide redox couples such as cysteine/ cystine (Cys/CySS) and reduced glutathione/oxidized glutathione (GSH/ GSSG) in plasma are useful indicators of systemic oxidative stress and other physiological states. This study describes a rather sensitive new method to determine the levels of Cys/CySS and GSH/ GSSG in plasma. Methods After removal of the red blood cells and proteins in rats' blood, iodoacetate was used to alkylate free thiols, followed by derivatization with dansyl. The levels of Cys/CySS and GSH/GSSG were separated by HPLC and the corresponding redox potentials(Eh) were caculated by Nernst equation. Results With high sensitivity and accuracy, this method can be used simultaneously to detect the levels of both Cys/CySS and GSH/GSSG in plasma and to calculate the corresponding redox potentials (Eh). Conclusion The study provides a more convenient and effective method to detect the redox environment of plasma that might be helpful for the diagnosis of clinical diseases related to oxidative stress.%目的 本研究拟探讨一种比较敏感、能同时检测血浆中半胱氨酸( cysteine,Cys)/胱氨酸(cystine,CySS)和还原型谷胱甘肽( reduced glutathione,GSH)/氧化型谷胱甘肽(oxidized glutathione,GSSG)含量及相应的氧化还原电势(Eh)的方法.方法 取大鼠全血,去除红细胞及蛋白后用碘乙酸封闭自由的巯基,通过丹磺酰氯衍生化后,利用高效液相色谱( high performance liquid chromatography,HPLC)进行分离,根据能斯特方程计算相应的氧化还原电势.结果 本方法可同时测定体内GSH/GSSG和Cys/CySS的含量及相应的氧化还原电势,灵敏度高、准确性强.结论 本研究提供了一种简便有效地检测血浆中氧化还原状态的方法,可能为诊断与氧化应激相关疾病提供新的依据.
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