Bagchi D, Carryl O R, Tran M X, Bagchi M, Garg A, Milnes M M, Williams C B, Balmoori J, Bagchi D J, Mitra S, Stohs S J
Creighton University School of Pharmacy & Allied Health Professions, Omaha, NE 68178, USA.
Mol Cell Biochem. 1999 Jun;196(1-2):109-16.
Reactive oxygen species (ROS) are implicated in the pathogenesis of stress-induced gastrointestinal mucosal injury. In the present study, we have investigated the effects of acute and chronic stress on the enhanced production of ROS including superoxide anion [SA; as determined by cytochrome c reduction (CCR)] and hydroxyl radicals (OH), and correlated the enhanced production of these free radicals with increased lipid peroxidation, membrane microviscosity and DNA fragmentation, indices of oxidative tissue damage, in the gastric and intestinal mucosa of female Sprague-Dawley rats. Furthermore, the protective ability of bismuth subsalicylate (BSS) against the gastrointestinal mucosal injury induced by acute and chronic stress was determined. Acute stress was induced for a period of 90 min, while chronic stress was induced for 15 min/day for 15 consecutive days. Half of the animals exposed to acute stress were pretreated orally with 15 mg BSS/kg 30 min prior to the exposure to acute stress. Similarly, half of the animals exposed to water-immersion restraint chronic stress were pretreated orally with 7.5 mg BSS/kg/day for 15 consecutive days 30 min prior to the exposure to chronic stress. Acute stress produced greater injury to both gastric and intestinal mucosa as compared to chronic stress. Acute stress increased CCR and OH production by 10.0- and 14.3-fold, respectively, in the gastric mucosa, and 10.4- and 17.0-fold, respectively, in the intestinal mucosa. Pretreatment with BSS prevented the acute stress-induced increase in CCR and OH production. Acute stress increased lipid peroxidation, DNA fragmentation and membrane microviscosity by 3.6-, 4.0- and 11.6-fold, respectively, in gastric mucosa, and 4.1-, 5.0- and 16.2-fold, respectively, in intestinal mucosa. BSS decreased acute stress-induced lipid peroxidation, DNA fragmentation and membrane microviscosity by approximately 26, 35 and 30%, respectively, in gastric mucosa, and by 20, 36 and 30%, respectively, in the intestinal mucosa. Chronic stress increased CCR and OH production by 4.8- and 6.3-fold, respectively, in gastric mucosa, and 4.6- and 6.9-fold, respectively, in intestinal mucosa. Chronic stress increased lipid peroxidation and DNA fragmentation by 2.9- and 3.3-fold, respectively, in gastric mucosa, and 3.3- and 4.2-fold, respectively, in intestinal mucosa. BSS decreased chronic stress-induced lipid peroxidation, DNA fragmentation and membrane microviscosity by approximately 41, 44 and 45%, respectively, in gastric mucosa, and by 39, 52 and 51%, respectively, in the intestinal mucosa. Daily administration of BSS provided greater protection against chronic stress-induced oxidative gastrointestinal injury as compared to the acute stress. These results demonstrate that both acute and chronic stress can induce gastrointestinal mucosal injury through enhanced production of ROS, and that BSS can significantly protect against gastrointestinal mucosal injury.
活性氧（ROS）与应激诱导的胃肠道黏膜损伤的发病机制有关。在本研究中，我们调查了急性和慢性应激对包括超氧阴离子[SA；通过细胞色素c还原（CCR）测定]和羟基自由基（OH）在内的ROS产生增加的影响，并将这些自由基产生的增加与雌性Sprague-Dawley大鼠胃和肠黏膜中脂质过氧化增加、膜微粘度增加和DNA片段化（氧化组织损伤指标）相关联。此外，还测定了次水杨酸铋（BSS）对急性和慢性应激诱导的胃肠道黏膜损伤的保护能力。急性应激诱导90分钟，而慢性应激连续15天每天诱导15分钟。暴露于急性应激的动物中有一半在暴露于急性应激前30分钟口服15 mg BSS/kg进行预处理。同样，暴露于水浸束缚慢性应激的动物中有一半在暴露于慢性应激前30分钟连续15天每天口服7.5 mg BSS/kg进行预处理。与慢性应激相比，急性应激对胃和肠黏膜造成的损伤更大。急性应激使胃黏膜中的CCR和OH产生分别增加10.0倍和14.3倍，使肠黏膜中的CCR和OH产生分别增加10.4倍和17.0倍。用BSS预处理可防止急性应激诱导的CCR和OH产生增加。急性应激使胃黏膜中的脂质过氧化、DNA片段化和膜微粘度分别增加3.6倍、4.0倍和11.6倍，使肠黏膜中的脂质过氧化、DNA片段化和膜微粘度分别增加4.1倍、5.0倍和16.2倍。BSS使急性应激诱导的胃黏膜脂质过氧化、DNA片段化和膜微粘度分别降低约26%、35%和30%，使肠黏膜中的脂质过氧化、DNA片段化和膜微粘度分别降低20%、36%和30%。慢性应激使胃黏膜中的CCR和OH产生分别增加4.8倍和6.3倍，使肠黏膜中的CCR和OH产生分别增加4.6倍和6.9倍。慢性应激使胃黏膜中的脂质过氧化和DNA片段化分别增加2.9倍和3.3倍，使肠黏膜中的脂质过氧化和DNA片段化分别增加3.3倍和4.2倍。BSS使慢性应激诱导的胃黏膜脂质过氧化、DNA片段化和膜微粘度分别降低约41%、44%和45%，使肠黏膜中的脂质过氧化、DNA片段化和膜微粘度分别降低39%、52%和51%。与急性应激相比，每日给予BSS对慢性应激诱导的胃肠道氧化损伤提供了更好的保护。这些结果表明，急性和慢性应激均可通过增强ROS的产生诱导胃肠道黏膜损伤，且BSS可显著保护胃肠道黏膜免受损伤。
