Grinberg L N, Rachmilewitz E A, Kitrossky N, Chevion M
Department of Hematology, Hadassah University Hospital, Jerusalem, Israel.
Free Radic Biol Med. 1995 Mar;18(3):611-5. doi: 10.1016/0891-5849(94)00160-l.
To provide more experimental evidence for the proposed role of oxygen free radicals in red blood cell (RBC) damage in beta-thalassemia, hydroxyl radical generation was studied in thalassemic (Th) vs. normal (N) RBC. .OH fluxes were quantified by the conversion of salicylic acid (SA) into its hydroxylated products, 2,3- and 2,5-dihydroxybenzoic acids (DHBA) and catechol, assayed with HPLC coupled to electrochemical detection. No significant difference in spontaneous .OH generation between N-RBC and Th-RBC was found. Ascorbic acid (0.5-3.0 mM) induced many-fold increases in SA hydroxylation in a dose-dependent manner in both types of cells. In the presence of ascorbate (1.0 mM), the SA hydroxylated products were determined in Th-RBC vs. N-RBC as follows (nmol/ml): 2,5-DHBA, 1.45 +/- 0.06 vs. 1.81 +/- 0.05 (p = 0.001); 2,3-DHBA, 1.89 +/- 0.21 vs. 1.15 +/- 0.08 (p = 0.008) and catechol, 0.87 +/- 0.13 vs. 0.38 +/- 0.05 (p = 0.006). The results showed significant increase in the total SA hydroxylation in Th-RBC as compared to N-RBC with a tendency to form 2,3-DHBA and catechol at the expanse of 2,5-DHBA. The excessive .OH generation in Th-RBC is attributed to the abnormally high content of redox active iron in the cytosolic and/or membrane compartments of these cells.
为了为所提出的氧自由基在β地中海贫血中红细胞（RBC）损伤中的作用提供更多实验证据，研究了地中海贫血（Th）与正常（N）红细胞中羟自由基的产生。通过将水杨酸（SA）转化为其羟基化产物2,3-和2,5-二羟基苯甲酸（DHBA）以及儿茶酚来定量.OH通量，并用与电化学检测联用的HPLC进行测定。未发现N-RBC和Th-RBC之间自发产生.OH有显著差异。抗坏血酸（0.5 - 3.0 mM）在两种类型的细胞中均以剂量依赖性方式诱导SA羟基化增加数倍。在存在抗坏血酸盐（1.0 mM）的情况下，Th-RBC与N-RBC中SA羟基化产物的测定结果如下（nmol/ml）：2,5-DHBA，1.45±0.06对1.81±0.05（p = 0.001）；2,3-DHBA，1.89±0.21对1.15±0.08（p = 0.008）；儿茶酚，0.87±0.13对0.38±0.05（p = 0.006）。结果表明，与N-RBC相比，Th-RBC中SA总羟基化显著增加，并且倾向于以2,5-DHBA为代价形成2,3-DHBA和儿茶酚。Th-RBC中过量的.OH产生归因于这些细胞的胞质和/或膜区室中氧化还原活性铁的异常高含量。
