不同潜水条件下暴露大鼠肺组织自由基的变化

目的　通过观察大鼠肺组织自由基变化 ,评价常规潜水和不减压潜水对机体的影响。方法　 77只 SD大鼠分别在 0 .5 MPa压缩空气中暴露 6 0 m in后用 83min(安全减压组 )或 1min(快速减压组 )减压 ,或在 1.0 MPa压缩空气中暴露 5 .5 min(5 .5 m in不减压组 )或 6 min(6 m in不减压组 )后用 40s减压。它们的对照组呼吸常压空气。减压后 6 0 m in腹腔注入 0 .0 6 m ol/L 的 PBN0 .5 ml/10 0 g,再过30 min放血处死 ,取 0 .75 g肺组织进行匀浆、离心 ,用 EPR波谱仪测定自由基强度 ,用分光光度计测定MDA含量、总抗氧化能力和 SOD活性。结果　 1快速减压组和 6 min不减压组都测到大量血流气泡 ,前者持久存在而后者存在时间很短 ,两组都有明显的行为改变。 2快速减压组 EPR信号显示自由基生成增多 (P<0 .0 5 )。 3快速减压组 MDA含量和总抗氧化能力升高 (P<0 .0 5 ) ,而 SOD活力下降 (P<0 .0 1) ;6 m in不减压组总抗氧化能力升高 (P<0 .0 5 )。结论　常规潜水快速减压使肺组织自由基生成增加 ,在不减压潜水组未发现自由基有明显变化

Changesof pulmonary tissue free radicals in rats exposed to different diving co nditions

Objective To observe the changes of free radicals in lung tissue of rats after conventional and non decompression dive and to evaluate the influences of these different forms of dive on the organism. Methods 77 SD rats were exposed to 0 5 MPa compressed air for 60 min then decompressed in 83 min(safe decompression group) or in 1 min(rapid decompression group) respectively, or exposed to 1 0 MPa compressed air for 5 5 min(5 5 min non decompression group) or 6 min(6 min non decompression group) respectively followed by a decompression of 40 s; meanwhile their respective control groups breathed normal pressure air. At 60 min after decompression, the animals were injected with 0 06 mol/L PBN 1 ml ip and were killed 30 min later by bloodletting. 0 75 g pulmonary tissue of each rat was taken, homogenized and centifuged. Free radicals were measured with EPR spectrometer. MDA concentration, total antioxidation capacity(TAO) and SOD activity of the tissue samples were detemined chemically. Results (1) Large amount of bubbles was detected in rapid decompression group and 6 min non decompression group with the lasting time longer in the former group. Besides, both groups showed behavioural changes. (2) Enhancement of free radical signals in EPR were shown in the rapid decompression group( P <0 05). (3) In rapid decompression group, both MDA concentration and TAO level rose( P <0 05) while SOD activity decreased very significantly( P <0 001); and in 6 min non decompression group, only the TAO level raised( P <0 05). Conclusions Conventional dive with rapid decompression could cause an increase of free radical generation in the lung tissue, whereas no significant change of free radical was found in the non decompression dive group.