硫化氢抑制低氧性肺动脉高压大鼠肺动脉细胞外基质的表达

Hydrogen sulfide inhibits the expression of extracelluar matrix in hypoxic pulmonary hypertension:experiment with rats

目的探讨硫化氢(H2S)抑制低氧性肺动脉高压(HPH)时肺动脉细胞外基质-弹力蛋白表达的变化。方法将Wistar大鼠24只随机均分为3组:缺氧组(腹腔注射生理盐水并放入常压低氧舱6h,共21d),缺氧+NaHS组(腹腔注射NaHS并放入常压低氧舱6h,共21d),和对照组(腹腔注射生理盐水)。实验结束时以右心导管测定3组大鼠的肺动脉平均压(mPAP),分离右心室(RV)和左心室加室间隔(LV+S),计算RV/LV+S比值,并以光学显微镜观测肺血管结构变化,用免疫组织化学方法研究α-平滑肌肌动弹白和弹力蛋白在肺动脉平滑肌细胞的表达含量。结果低氧组的mPAP和RV/(LV+S)比值为(3·15±0·17)kPa及(0·41±0·03)kPa,均明显高于对照组〔(2·09±0·23)kPa及(0·29±0·02)kPa,P<0·01〕。低氧+NaHS组的mPAP和RV/(LV+S)比值为(2·17±0·22)kPa及(0·31±0·02)kPa,均明显低于低氧组(P<0·01),但与对照组间差异无统计学意义。低氧组的肺小动脉中肌型动脉、部分肌型动脉百分比分别为23·89%±6·81%及24·96%±4·36%,均明显高于对照组(14·56%±7·43%及16·54%±4·54%,P<0·05,P<0·01);低氧组的非肌型动脉百分比为51·15%±6·68%,显著低于对照组(68·91%±2·83%,P<0·01)。低氧+NaHS组的肌型、部分肌型动脉百分比为15·61%±3·08%及17·74%±2·93%,均显著低于低氧组,但与对照组间差异无统计学意义;其非肌型动脉百分比为66·65%±4·17%,明显高于低氧组(P<0·01),但与对照组间差异无统计学意义。低氧组中小肺动脉平滑肌的a-SM-肌动蛋白质表达水平为49·93%±6·31%及56·89%±6·42%,均显著高于对照组(23·89%±3·91%及27·45%±3·34%,P<0·01)。低氧+NaHS组中小肺动脉平滑肌的α-SM-肌动蛋白表达水平分别为29·01%±4·02%及34·78%±3·42%,均显著低于低氧组(P<0·01),但与对照组间差异无统计学意义。低氧组中小肺动脉平滑肌的弹力蛋白表达水平分别为57·75%±7·29%及59·75%±6·61%,均显著高于对照组(30·88%±2·80%及32·19%±3·55%,P<0·01)。低氧+NaHS组中、小肺动脉平滑肌的弹力蛋白表达水平分别为37·63%±6·16%及36·88%±6·46%,均显著低于低氧组(P<0·01),但与对照组间差异无统计学意义。结论硫化氢可能通过抑制HPH时细胞外基质成份之一的弹力蛋白的表达,调节低氧性肺血管结构重建和HPH的形成。

Objective To investigate the inhibitory effects of hydrogen sulfide on the expression of elastin,an extracelluar matrix,in hypoxic pulmonary hypertensive(HPH).Methods Twenty-four Wistar rats were randomly divided into three equal groups:hypoxic group,injected intraperitoneally with normal saline(NS) and then put in the low-oxygen cabin under normal pressure for 6h,once a day for 21 days,hypoxia+NaHS group,injected intraperitoneally with sodium hydrogen sulfide(NaHS) and then put into low-oxygen cabin under normal pressure once a day for 21 days,and control group,injected intraperitoneally with NS qd.By the end of experiment mean pulmonary artery pressure(mPAP) was measured via right ventricular catheterization.Then the rats were killed and the hearts were taken out to calculate the weight of right ventricle/weight of left ventricle+septum ratio(RV/LV+S).The percentage of muscularized arteries of medium and small pulmonary arteries was measured by light microscopy.Immunohistochemistry was used to detect the expression of a-smooth-muscle actin(a-SM actin) and elastin in the pulmonary artery smooth muscle cells.Results The mPAP and RV/LV+S of the hypoxic group were 3.15±0.17 kPa and 0.41±0.03 respectively,both significantly higher than those of the control group(2.09±0.23 kPa and 0.29±0.02 respectively,both P<0.01).The mPAP and RV/LV+S of the hypoxia+NaHS group were 2.17±0.22 kPa and 0.31±0.02 respectively,both significantly lower than those of the hypoxic group(both P<0.01),however,not significantly different from those of the control group.The percentage of muscularized and partly muscularized arteries in the small pulmonary arteries of the hypoxic group were 23.89±6.81% and 24.96±4.36% respectively,both significantly higher than those of the control group(14.56±7.43% and 16.54±4.54% respectively,P<0.05,P<0.01);and the percentage of unmuscularized arteries in small pulmonary arteries of the hypoxic group was 51.15±6.68%,significantly lower than that of the control group(68.91±2.83%,P<0.01) The percentage of muscularized and partly muscularized arteries in small pulmonary arteries of the hypoxic+NaHS group were 15.61±3.08% and 17.74±2.93% respectively,both significantly lower than those of the hypoxic group,and the percentage of unmuscularized arteries in small pulmonary arteries of the hypoxic+NaHS group was 66.65±4.17%,significantly higher than that of the hypoxic group(P<0.01),but not significantly different from that of the control group.The expression levels of a-SM-actin in median and small pulmonary artery smooth muscle cells of the hypoxic group were 49.93±6.31% and 56.89±6.42% respectively,both significantly higher than those of the control group(23.89±3.91% and 27.45±3.34% respectively,both P<0.01).The expression levels of a-SM-actin in median and small pulmonary artery smooth muscle cells of the hypoxia+NaHS group were 29.01±4.02% and 34.78±3.42% respectively,both significantly lower than those of the hypoxic group(both P<0.01),however,not significantly different from those of the control group.The expression levels of elastin in the median and small pulmonary artery smooth muscle cells of the hypoxic group were 57.75±7.29% and 59.75±6.61% respectively,both significantly higher than those of the control group(30.88±2.80% and 32.19±3.55% respectively,both P<0.01).The expression levels of elastin in the median and small pulmonary artery smooth muscle cells of the hypoxic+NaHS group were 37.63±6.16% and 36.88±6.46% respectively,both significantly lower than those of the hypoxic group(both V0.01),however,not significantly different from those of the control group.Conclusion Hydrogen sulfide plays a modulatory role on hypoxic pulmonary vascular structural remodeling and the development of HPH by inhibiting the expression of elastin of extracelluar matrix.