硫化氢对低氧性肺动脉高压中氧化应激的调节作用

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180～200 g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21 d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(superoxide dismutase ,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(hydroxy radical,[·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) mm Hg vs. (16.3±3.7) mm Hg, 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) mm Hg, 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.

Effect of hydrogen sulfide on oxidative stress in hypoxic pulmonary hypertension

OBJECTIVE: To study the modulatory effect of hydrogen sulfide (H(2)S) 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+NaHS group (n=8). Hypoxic challenge was performed everyday for 21 days. NaHS solution was injected intra-peritoneally everyday before hypoxic challenge for rats in the hypoxia+NaHS 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+septum [RV/(LV+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, the mPAP[(23.7+/-2.2) mm Hg vs (16.3+/-3.7) mm Hg,P<0.01] and the weight ratio of RV/(LV+SP) increased (P<0.01), but lung tissue T-AOC was decreased by 21.4% (P<0.01).But GSSG was increased by 68.5% (P<0.01) as compared with those of the control rats. However, compared with those of the hypoxic group, the mPAP in rats of hypoxia+NaHS group was decreased [(16.3+/-2.8) mm Hg vs (23.7 +/-2.2) mm Hg]. Administration of NaHS increased T-AOC by 18.8% (P<0.05) but eliminated GSSG by 23.2% (P<0.05) in rats of hypoxia+NaHS 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.