Pharmacology Division, U.S. Army Medical Research Institute of Chemical Defense, 3100 Ricketts Point Road, Aberdeen Proving Ground, Maryland 21010-5400.
Toxicol Mech Methods. 2004;14(3):195-202. doi: 10.1080/15376520490429120.
Sulfur mustard (SM) is a blistering agent that produces DNA strand breaks. To detect SM-induced DNA single strand breaks in human peripheral blood lymphocytes (PBL), cells were exposed to various concentrations of SM (10 to 1000 muM), and the comet assay (single-cell gel electrophoresis) was performed. We observed a SM concentration- and time-dependent increase in detectable DNA damage. To test whether SM-induced DNA cross-linking inhibits DNA migration in the comet assay, PBL were exposed to a) SM alone (10 to 1000 muM), b) H(2)O(2) (0.001%), which produces DNA single strand breaks with no cross-links, or c) SM followed at 2, 4, or 6 h by H(2)O(2). With H(2)O(2) alone, a large amount of strand breakage was detected. With H(2)O(2) plus SM, detectable H(2)O(2)-induced strand breaks decreased as SM concentration increased up to 30 muM; at 30 muM and above, the response with H(2)O(2) plus SM was similar to that with SM alone. Interference with the detection of H(2)O(2)-induced DNA strand breaks appears to be SM concentration-dependent up to 30 muM, and independent of SM concentration at >/=30 muM. This is presumably due to SM-induced cross-linking. It follows that cross-linking in DNA of SM-exposed PBL also interferes with DNA migration and detection of DNA strand breaks when cells are exposed to SM alone.
芥子气（SM）是一种起泡剂，会导致 DNA 链断裂。为了检测人外周血淋巴细胞（PBL）中 SM 引起的 DNA 单链断裂，将细胞暴露于各种浓度的 SM（10 至 1000 μM），并进行彗星试验（单细胞凝胶电泳）。我们观察到 SM 浓度和时间依赖性地增加了可检测的 DNA 损伤。为了测试 SM 诱导的 DNA 交联是否抑制彗星试验中的 DNA 迁移，将 PBL 暴露于以下条件：a）单独的 SM（10 至 1000 μM），b）H2O2（0.001%），其产生没有交联的 DNA 单链断裂，或 c）SM 之后在 2、4 或 6 小时分别加入 H2O2。单独使用 H2O2 时，检测到大量的链断裂。当 H2O2 与 SM 一起使用时，随着 SM 浓度的增加，可检测到的 H2O2 诱导的链断裂减少，直至达到 30 μM；在 30 μM 及以上，H2O2 与 SM 一起使用的反应与单独使用 SM 时相似。与 H2O2 诱导的 DNA 链断裂的检测干扰似乎在 30 μM 及以下时与 SM 浓度有关，而在 30 μM 及以上时与 SM 浓度无关。这大概是由于 SM 诱导的交联所致。因此，当细胞单独暴露于 SM 时，SM 暴露的 PBL 中的交联也会干扰 DNA 迁移和 DNA 链断裂的检测。
