Hiraishi H, Shimada T, Ivey K J, Terano A
Second Department of Internal Medicine, Dokkyo University School of Medicine, Mibu, Tochigi, Japan.
J Pharmacol Exp Ther. 1999 Apr;289(1):103-9.
Reactive oxygen species appears to be involved in the pathogenesis of ethanol-induced gastric mucosal injury in vivo. Because ingested ethanol diffuses into the gastric mucosa, targeting both epithelium and endothelium, in the present study we examined the possible protective effect of antioxidants on ethanol damage in gastric epithelial cells and endothelial cells in vitro. Cytotoxicity by ethanol was quantified by measuring 51Cr release. The effects of impairment of the glutathione redox cycle and of inhibition of cellular catalase were examined. The generation of superoxide was assessed by the reduction in cytochrome c. Ethanol caused a time- and dose-dependent increase in 51Cr release from epithelial cells. Incubation of cells with DL-buthionine-(S,R)-sulfoximine, while reducing glutathione production, dose dependently enhanced ethanol-induced injury. 1,3-Bis(chloroethyl)-nitrosourea, while inhibiting glutathione reductase activity, also sensitized cells to ethanol. In contrast, the inhibition of catalase with 3-amino-1,2, 4-triazole did not alter the susceptibility of epithelial cells to ethanol. Ethanol induced damage to endothelial cells in a similar fashion. In endothelial cells, however, neither impairment of the glutathione cycle nor inhibition of catalase influenced ethanol-induced damage. Epithelial cells, when exposed to ethanol, increased superoxide production as a function of ethanol concentration, whereas endothelial cells did not. The glutathione redox cycle, but not cellular catalase, plays a critical role in protecting epithelial cells against ethanol damage, whereas neither antioxidant seems to play a role in protection of endothelial cells. The distinct difference in antioxidant protection against ethanol appears to depend on the capability of each cell to produce cytotoxic oxygen species in response to ethanol exposure.
活性氧似乎参与了体内乙醇诱导的胃黏膜损伤的发病机制。由于摄入的乙醇扩散到胃黏膜中，同时作用于上皮细胞和内皮细胞，因此在本研究中，我们检测了抗氧化剂对体外培养的胃上皮细胞和内皮细胞中乙醇损伤的可能保护作用。通过测量51Cr释放来定量乙醇的细胞毒性。研究了谷胱甘肽氧化还原循环受损和细胞过氧化氢酶抑制的影响。通过细胞色素c的还原评估超氧化物的产生。乙醇导致上皮细胞中51Cr释放呈时间和剂量依赖性增加。用DL-丁硫氨酸-（S，R）-亚砜亚胺孵育细胞，在减少谷胱甘肽生成的同时，剂量依赖性地增强了乙醇诱导的损伤。1,3-双（氯乙基）-亚硝基脲在抑制谷胱甘肽还原酶活性的同时，也使细胞对乙醇敏感。相反，用3-氨基-1,2,4-三唑抑制过氧化氢酶并没有改变上皮细胞对乙醇的敏感性。乙醇以类似的方式诱导内皮细胞损伤。然而，在内皮细胞中，谷胱甘肽循环的受损和过氧化氢酶的抑制均未影响乙醇诱导的损伤。上皮细胞暴露于乙醇时，超氧化物的产生随乙醇浓度增加而增加，而内皮细胞则不然。谷胱甘肽氧化还原循环而非细胞过氧化氢酶在保护上皮细胞免受乙醇损伤中起关键作用，而两种抗氧化剂似乎都不参与内皮细胞的保护。抗氧化剂对乙醇保护作用的明显差异似乎取决于每个细胞响应乙醇暴露产生细胞毒性氧物种的能力。
