门静脉高压形成中内源性硫化氢体系的变化及其对一氧化氮/一氧化氮合酶途径的影响

目的 研究新型气体信号分子硫化氢(hydrogen sulfide,H2S)在大鼠门静脉高压形成中的作用以及对内源性一氧化氮(nitric oxide,NO)/一氧化氮合酶(nitric oxide synthase,NOS)体系的调节作用,以深入探讨H2S在大鼠门静脉高压形成中的病理生理意义.方法 将30只健康SD大鼠随机分为4组:正常组(5只),假手术组(5只),部分门静脉结扎(partly portal vein ligation,PPVL)组(10只)及PPVL+NaHS组(10只).模型制作14 d后,分别测定各组大鼠的门静脉压力(portal venous pressure,PVP)和平均动脉压力(systemic mean arterial pressure,MAP);采用免疫组织化学方法榆测大鼠肝脏中胱硫醚-γ-裂解酶(cystathionine-γ-lyase,CSE)和NOS蛋白表达情况,RT-PCR方法检测肝脏中CSE和NOS mRNA表达情况.结果 术后14 d,假手术组和正常组各项检测指标未见显著差异.与正常组比较,PPVL组PVP明显增高(P＜0.01),MAP下降(P＜0.05);外源件给予H2S的供体-NaHS后,与PPVL组比较,PPVL+ NaHS组PVP进一步增高(P＜0.05),MAP进一步下降(P＜0.05).CSE、NOS3在各组大鼠的肝脏中均有表达.与正常组比较,PPVL组CSE蛋白及mRNA表达增加(P＜0.05);外源性给予NaHS后,其表达则进一步增加(P＜0.05).NOS2在正常组和假手术组未见明显表达,部分门静脉结扎后,大鼠肝脏中可见NOS2蛋白及mRNA表达,外源性给予NaHS后,其表达降低(P＜0.05).但是,NOS3蛋白及mRNA表达在各组之间无显著差异.结论 H2S参与了门静脉高压的形成与发展,外源性给予NaHS可以加重门静脉高压,内源性H2S的高水平可以抑制NOS的生成.

Changes of hydrogen sulfide and its impact on nitric oxide/ nitric oxide synthase system in portal hypertensive rats

Objective To explore the changes of hydrogen sulfide and its impact on nitric oxide/ nitric oxide synthase system in portal hypertension rats.Methods Thirty SD rats were randomly divided into the normal group(n=5),sham-operated group(n=5),PPVL group (n=10) and PPVL+NaHS group (n=10).In PPVL group and PPVL+NaHS group,portal hypertension was established through the operation of partly portal vein ligation (PPVL).Two weeks later,portal vein pressure (PVP) and systemic arterial pressure (MAP) were measured.The immunohistochemical method was used for detection of expression of CSE and NOS in liver,and RT-PCR for that of CSEmRNA and NOSmRNA.Results After 14 days,there were no significant differences in the indexes between the sham-operated group and the normal group.Compared with normal group,PVP was increased significantly in PPVL group (P＜0.01 ),but MAP was decreased (P＜0.05).Compared with PPVL group,PVP was also increased in PPVL+ NariS group (P＜0.05),and MAP was decreased too (P＜0.05).Both CSE and NOS3 and the mRNA of them were expressed in the liver of rats.Compared with normal group or sham-operated group,the expression of CSE and the mRNA expression of it were increased in PPVL group (P＜0.05).Compared with PPVL group,the expression of CSE was increased too in PPVL+NaHS group (P＜0.05).NOS2 did not expressed in liver in normal group and sham-operated group.However,it was found after the operation of PPVL.Compared withPPVL group,the expression of NOS2 was decreased in PPVL+NaHS group.On the other hand,the expression of NOS3 protein and mRNA was of no significant difference among different groups.Conclusion Endogenous H2S is involved in the formation and development of portal hypertension.Exogenous application of H2S can aggravate the portal hypertension for the high level of endogenous H2S can inhibit the generation of NOS.