硫化氢对局灶性脑缺血大鼠脑组织氧化应激的影响

目的：观察硫化氢（H2 S）对局灶性脑缺血大鼠脑组织氧化应激的影响。方法40只健康雄性 SD 大鼠，随机分为假手术（Sham）组、缺血模型（Ischemia）组、H2 S 低剂量（L-NaHS）组、H2 S 中剂量（M-NaHS）组和 H2 S 高剂量（H-NaHS）组。线栓法复制大鼠大脑中动脉闭塞模型。H2 S 低、中、高剂量组大鼠于缺血3 h 时分别腹腔注射0.7 mg/ kg、1.4 mg/ kg 和2.8 mg/ kg 的 NaHS，Sham 组和 Ischemia 组注射等容量的0.9%氯化钠溶液。5组大鼠均于缺血24 h 时断头取脑，测定脑组织中丙二醛（ MDA）的含量、超氧化物歧化酶（ SOD）的活性和谷胱甘肽过氧化物酶（GSH-PX）的活性；透射电镜观察脑组织的病理变化。结果与 Sham 组比较，Ischemia 组大鼠脑组织 SOD、GSH-PX 活性明显降低（ P ﹤0.01），MDA 含量明显升高（ P ﹤0.01）；电镜观察显示神经元水肿，线粒体膜肿胀、线粒体嵴断裂甚至消失，线粒体大量空泡化，细胞器的数量减少；与 Ischemia 组比较，M-NaHS、H-NaHS 组大鼠脑组织中 SOD、GSH-PX活性明显升高（ P ﹤0.05），MDA 含量明显降低（ P ﹤0.05）；电镜观察可见神经元轻度水肿，线粒体部分肿胀、内外膜结构清晰、部分嵴断裂消失，细胞器数量增多，脑缺血损伤程度明显减轻。结论 H2 S 可减轻大鼠局灶性脑缺血损伤，其机制与提高大鼠的抗氧化应激能力有关。

Effects of hydrogen sulfide on oxidative stress of brain tissues in rats with focal cerebral ischemia

Objective To observe the effects of hydrogen sulfide(H2S)on oxidative stress of brain tissues in rats with focal cerebral ischemia,and to explore possible action mechanism. Methods Forty healthy male SD rats were randomly divided into five groups:sham operation group(group S),ischemia model group(group I),low-dose H2 S group(group L), median-dose H2 S group(group M)and high-dose H2 S group(group H). The rats were anesthetized by 10% chloral hydrate at a concentration of 350mg/ kg. The animal models with middle cerebral artery occlusion were established by thread ligation method. However the rats in group S underwent a surgical operation,without thread ligation. The rats in group L,M,H were given H2 S(0. 7mg,1. 4mg and 2. 8mg/ kg,respectively)at 3h after cerebral ischemia,however,the rats in group S and group I were given equal volume of 0. 9% sodium chloride solution. These rats were sacrificed at 24h after cerebral ischemia. The content of malondialdehyde(MDA),the activities of superoxide dismutase(SOD)and glutathione peroxidase(GSH-PX)in brain tissue were detected,furthermore,the ultrastructure changes of neurons were observed by transmission electron microscopy. Results As compared with those in group S ,the activities of SOD and GSH-PX were significantly decreased, however,the content of MDA was obviously increased in group I( P ﹤ 0. 01). The results by transmission electron microscopy showed neuron edema,mitochondria swelling,that the cristae of mitochondria was disrupted,dissolved or disappeared,the amount of organelles was obviously decreased in group I. As compared with those in group I,the activities of SOD and GSH-PX were significantly increased,however,the content of MDA was obviously decreased in group M and group H( P ﹤ 0. 05). The results by transmission electron microscopy showed slight neuron,part mitochondria swelling,that the cristae of mitochondria was partly disrupted,dissolved or disappeared,the amount of organelles was increased,moreover,the injury degree of cerebral ischemia was obviously alleviated in group M and group H. Conclusion H2 S can relieve focal cerebral ischemic injury in rats,and its action mechanism may be correlated to increasing the antioxidative stress ability of rats.