The Role of Hydroxyl Radical in Brain Injury Induced by Hyperbaric Oxygen Exposure

• Main Authors: Lin, Yi-Shing, 林宜興
• Other Authors: Wan, Fang-Jung
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/43842732281894804377

碩士 === 國防醫學院 === 海底醫學研究所 === 88 === Hyperbaric oxygen (HBO2) has been shown to promote healing in clinical treatment of a number of medical conditions, which include decompression sickness, CO poisoning, burn injury and so on. The use of HBO2 is limited by its toxicity, but unclearly, free radical formation seems to be one of the mechanisms involved in the HBO2 toxicity. The present study, using both in vivo and in vitro approaches, was to investigate whether pretreatment Phenyl-N-tert-butylnitrone (PBN) suppress free radical formation and prolong the seizure latency during exposure to HBO2, and whether PBN protect the primary cortical cultures from HBO2-induced neurotoxicity. First, S-D rats were used in this study. The animals were divided into four groups: pre-treatment with PBN for 30 min; exposed to 6 ATA 100 % O2 HBO2 for 30 min; pre-treatment with PBN and exposed to 6 ATA 100 % O2 HBO2 for 30 min, while control group to 1 ATA room air exposure for 30 min. After HBO2 exposure animals were decapitated immediately and the striatum, hippocampus and the cortex were harvested for the analysis of 2,3-DHBA, a marker for hydroxyl radical, using HPLC-ECD. Second, neonatal S-D rat primary cortical cultures were divided into several groups: 1 ATA room air exposure for 90 min; 6 ATA HBO2 exposure for 90 min; pretreatment with PBN-3mM and 6 ATA HBO2 exposure for 90 min. The HBO2 experiment began at the 7th day after cultures (DIV 7). After exposure, medium samples at 24 hr were collected, and we measured the level of lactate dehydrogenase (LDH) and methylthiazol tetrazolium (MTT) by a spectrophotometer. Third, neonatal S-D rat primary cortical cultures were divided into five groups: 1 ATA room air exposure for 90 min; 6 ATA HBO2 exposure for 90 min; pretreatment with DMSO（1%）and 6 ATA HBO2 exposure for 90 min; pretreatment with DEVD-fmk 5μM and 6 ATA HBO2 exposure for 90 min; pretreatment with DEVD-fmk 50μM and 6 ATA HBO2 exposure for 90 min. The HBO2 experiment began at the 7th day after cultures (DIV 7). At 24 hr after exposure, medium samples were collected, and we measured the lactate dehydrogenase (LDH) activity and methylthiazol tetrazolium (MTT) by a spectrophotometer. Our data indicated that HBO2 exposure increased the formation of 2,3-DHBA in the striatum and cortex of S-D rats, and pretreatment with PBN repress 2,3-DHBA formation. In vitro study showed that HBO2 exposure resulted in LDH release and MTT reduction in S-D rat cortical cultures.