摘要
观察高压氧（ＨＢＯ）惊厥大鼠脑突触体、线粒体的脂质过氧化物（ＬＰＯ）和突触体氨基酸递质水平的变化，以及抗氧化剂还原型谷胱甘肽（ＧＳＨ）预防氧惊厥的作用及其机理的探讨。方法实验用ＳＤ大白鼠，分为对照组（常压空气）、ＨＢＯ组（０．５５ＭＰａ，３０ｍｉｎ）和ＧＳＨ加ＨＢＯ组。进氧舱前３０ｍｉｎ，按８ｍｍｏｌ／ｋｇ腹腔内注射ＧＳＨ溶液或等容积０．９％ＮａＣｌ。按Ｇｒａｙ和Ｗｈｉｔｔａｋｅｒ方法制备突触体和线粒体，以Ｏｈｋｗａ方法测定ＬＰＯ含量与王自勉等方法测定突触体内氨基酸含量。结果ＨＢＯ组大鼠脑突触体和线粒体的ＬＰＯ含量显著增加，而突触体内Ｙ－氨基丁酸（ＧＡＢＡ）、牛磺酸（ｔａｕｒｉｎｅ）含量显著下降；氧暴露前预先给予ＧＳＨ，可防止ＨＢＯ引起的突触体内ＧＡＢＡ水平的降低，减少突触体ＬＰＯ的生成。结论氧惊厥的发生与脑内氧自由基生成增加，引起突触体和线粒体膜脂质过氧化作用增强，以及神经递质代谢紊乱有关。
IM The changes of lipid peroxides(LPO)contents in synaptosome and mitochondria and thechanges of anuno acid transmitter levels in synaptosome of brain with hyperbaric oxygen(HBO)-inducedconvulsions were examined in rats,In addition,the protective effect of antioxidant-reductive glutathion(GSH)against HBO-induced convulsions and its mechanisnis were investigated.METHODS The experiments were carried out in 40 SD-strain rats,GSH(8 mmol/kg)was injected intraperitoneally 30min before the HBO exposure. A hyperbaric chamber with a capacity of about 0.1m3 was used. Afterflushing the chamber twice with pure oxygen, the chamber was closed and the pressure was raised to 0.55 MPa and sustained for 30 min. During this 30 min period intermittent oxygen influxion was conduct- ed to maintain its purity inside the chamber.After this period a rapid decompression within 2～3minwas made and the animals were taken out of the chamber and were decapitated immediately with theirbrains cut out in 1～2min.A 10%brain homogenate in cold (0～4℃)0. 32 mol/L sucrose was pre- pared in a Teflon- glass homogenizer.Synaptosomal and mitochondria fractions were obtained accordingto the method of Gray and Whittaker.LPO conrent in synaptosome and mitochondria was quantitatedaccording to the method of Ohkwa,Protein was measured according to the method of Lowry et al.GA- BA and taurine contents in synaptosome were measured according to the method of Wang Zimian et al.RESULTS(1)When convulsioris appeared after the rats were exposed to HBO,the LPO content in synaptosome(3. 51 ± 1. 05 nmol/mg prot);and mitochondria (3. 96±0. 60 nmol/mg prot) increased sig-nificantly as compared with that in control fIroup(P<0. 05,P<0. 01),and the GABA and tnurine con -tents in synaptosome(11. 60± 2. 03 and 23.91 ± 7. 16 nmol/mg prot)decreased significantly as com-pared with that in control group(P<0.01).(2)When the rats were injected intraperitoneally with GSH(8 mmol/kg)30 min before HBO exposure,the stipposed convtilsion may be prevented,the GA-BA content in synaptosome(15.17±0.89 nmol/mg prot)increased significantly as compared with that in HBO group without the use of GSH(P<0.05), and the LPO content in synaptosome(1.88±0. 90 nmol/mg prot)decreased significantly as compared with that in HBO group without the use of GSH(P<0. 05) CONCLUSION The HBO-induced convulsions may be related to the increase of LPO con-tent in synaptosome and mitochondria of the brain and also to the metabolic disorder of the neurotrans-mitters in synaptosomes.
关键词
氧中毒
氧惊厥
突触体
线粒体
过氧化脂质
Hyperbaric Oxygen Convulsions Synaptosome Mitochondondria Lipid per-oxide Y- aminobutyric acid Taurine Glutathion
