硫化氢对低氧性肺动脉高压中氧化应激的调节作用

Effect of hydrogen sulfide on oxidative stress in hypoxic pulmonary hypertension

目的：探讨硫化氢（H2S）对低氧性肺动脉高压（hypoxic pulmonary hypertension，HPH）形成中氧化应激的调节作用。方法：选取体重180～200g的健康雄性Wistar大鼠20只，随机分为对照组、低氧组、低氧＋硫氢化钠（NaHS）组。建立低氧模型21d后，监测其血液动力学变化；应用比色法检测肺组织匀浆中超氧化物歧化酶（super．oxidedismutase，SOD）、总抗氧化能力（total antioxidant capacity，T—AOC）、氧化型谷胱甘肽（oxidized glutathione，GSSG）、还原型谷胱甘肽（reduced glutathione，GSH）、丙二醛（malondiadehyde，MDA）、羟自由基（hydroxyradical，·OH）的含量；应用实时荧光定量PCR的方法检测SOD基因转录水平的变化。结果：经3周低氧处理，大鼠形成HPH和肺血管结构重构，表现为平均肺动脉压（mean pulmonary arterial pressure，mPAP）明显增加[（23．7±2．2）mmHg vs（16．3±3．7）mmHg，P〈0．01]，右室重量与左室及室间隔重量的比值[RV／（LV＋SP）]升高（P〈0．01）；给予外源性H2S供体NaHS后，可以降低肺动脉压力[（16．3±2．8）mm Hg vs（23．7±2．2）mmHg，P〈0．01]，减少RV／（LV＋SP）（P〈0．01）；H2S供体可以提高T-AOC 18．8％（P〈0．01），减少GSSG的含量23．2％（P〈0．01），但对SOD的活性及基因转录水平无明显影响。结论：H2S在HPH形成中的氧化应激过程中发挥抗氧化作用，其作用机制部分是通过减少GSSG的含量，从而提高机体的抗氧化能力。

Objective： To study the modulatory effect of hydrogen sulfide （H2S） on oxidative stress in the development of pulmonary hypertension induced by hypoxia. Methods：Twenty male Wistar rats were randomly divided into control group （ n = 6 ）, hypoxic group （ n = 6 ） and hypoxia ＋ NariS group （ n = 8 ）. Hypoxic challenge was performed everyday for 21 days. NariS solution was injected intra-peritoneally everyday before hypoxic challenge for rats in the hypoxia 4- NariS group. After 21 days of hypoxia, the mean pulmonary artery pressure （mPAP） was measured by cardiac catheterization. The weight ratio of right ventricle to left ventricle 4- septum [ RV/（ LV 4- SP） ] was also measured. The lung homogenates were assayed for total antioxidant capacity（ T-AOC）, superoxide dismutase （SOD）, oxidized glutathione （ GSSG）, reduced glutathione （ GSH）, malondiadehyde （MDA） and hydroxy radical （ · OH ）, and the SOD mRNA levels were assayed by real time polymerse chain reaction. Results： After three weeks of hypoxic disposure, hypoxic hypertension and vascular remodeling developed. Compared with the control group, themPAP[（23.7±2.2） mm Hgvs. （16.3 ±3.7） mm Hg,P〈0.01] and the weight ratio of RV/（ LV ＋ SP） increased （P 〈 0.01 ） But GSSG was increased by 68.5 % （ P 〈 0. lung tissue T-AOC was decreased by 21.4% （P 〈 0.01 ）. 01 ） as compared with those of the control rats. However, compared with those of the hypoxic group, the mPAP in rats of hypoxia ＋ NariS group was decreased [ （16.3 ±2.8） mm Hg vs. （23.7 ±2.2） mm Hg]. Administration of Naris increased T-AOC by 18.8% （P 〈 0.05 ） but eliminated GSSG by 23.2% （ P 〈 0.05 ） in rats of hypoxia ＋ NariS group as compared with the hypoxic group. There were no significant changes in lung tissue SOD mRNA level and its capacity among the three groups. Conclusion： Hydrogen sulfide acted as antioxidant during the oxidative stress of hypoxic pulmonary hypertension, and the mechanism was partly through attenuating the content of GSSG.