Gulhane Military Medical Academy, Department of Undersea and Hyperbaric Medicine, Ankara, Turkey.
Inhal Toxicol. 2011 Feb;23(3):166-72. doi: 10.3109/08958378.2011.558528.
Despite its known benefits, hyperbaric oxygen (HBO) is also reported to enhance the production of reactive oxygen species and can cause oxidative stress in several tissues. Previous studies had shown that HBO-induced oxidative stress is directly proportional to both its exposure pressure and duration. Nevertheless, these studies were usually performed with single-session HBO exposure but its clinical use commonly depends on long-term exposure periods.
To clarify the oxidative effect of long-term repetitive HBO in the lung tissue of rats.
Male Sprague-Dawley rats were divided into six study groups exposed to consecutive HBO sessions (2.8 atm/90 min) for 5, 10, 15, 20, 30, and 40 days. Animals were sacrificed 24 h after the last HBO session. An additional control group was set to obtain normal data. Lung malondialdehyde (MDA) and carbonylated protein (PCC) levels were determined as measures of oxidative stress along with the activities of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase.
None of the measured parameters showed any changes among the groups exposed to 5-15 HBO sessions. However, MDA, PCC, and SOD were found to be significantly increased in the 20 to 40 session groups.
These results indicate that repetitive treatment with HBO may cause oxidative stress in critical tissues including the lung. Although HBO-mediated free radicals are accepted to be responsible for the benefits of this therapeutic modality, especially in cases with prolonged exposure, possible injurious effects of supranormal values of bio-oxidative products need to be considered.
尽管已知高压氧（HBO）有诸多益处，但它也被报道可增强活性氧的产生，并可导致几种组织发生氧化应激。先前的研究表明，HBO 诱导的氧化应激与暴露压力和持续时间成正比。然而，这些研究通常使用单次 HBO 暴露进行，但 HBO 的临床应用通常取决于长期暴露期。
阐明大鼠肺组织中长期重复 HBO 暴露的氧化作用。
雄性 Sprague-Dawley 大鼠被分为六组，分别接受连续 HBO 治疗（2.8 个大气压/90 分钟）5、10、15、20、30 和 40 天。最后一次 HBO 治疗后 24 小时处死动物。另设一组正常对照组以获取正常数据。肺组织丙二醛（MDA）和羰基化蛋白（PCC）水平作为氧化应激的指标进行测定，同时还测定了抗氧化酶超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶的活性。
在接受 5-15 次 HBO 治疗的组中，没有一个测量参数发生变化。然而，在 20-40 次治疗组中，MDA、PCC 和 SOD 显著增加。
这些结果表明，重复 HBO 治疗可能会导致包括肺在内的关键组织发生氧化应激。虽然 HBO 介导的自由基被认为是这种治疗方式的益处的原因，特别是在长时间暴露的情况下，但需要考虑生物氧化产物的超正常值可能造成的有害影响。
