硫化氢对大鼠血管舒张反应及血管组织环磷酸鸟苷水平的影响

Effect of hydrogen sulfide on vasorelaxation and content of guanosine 3＆#39;, 5＆#39;-cyclic phosphate in vascular tissue of rats

目的 研究硫化氢（H2S）对大鼠血管舒张反应及血管组织环磷酸鸟苷（cGMP）水平与环核苷酸磷酸二酯酶（PDE）活性的影响.方法 选用硫氢化钠溶液作为H2S的供体,采用离体大鼠胸主动脉血管环灌流的方法,观察H2S的血管舒张效应.采用酶联免疫吸附法检测经H2S孵育前后血管组织中cGMP水平,采用PDE活性检测试剂盒检测PDE的活性.结果 1.H2S可引起大鼠血管舒张,其引起最大舒张效应值的50％时对应的H2S浓度（EC50）为（1.79±0.31） ＆#215;10-5 mol/L.2.经过50 μmol和300 μmol的H2S孵育后的大鼠血管组织cGMP水平分别为（41.45±7.49） pmol/L和（31.35±2.56） pmol/L,明显高于基础值[（22.29±1.59）pmol/L]（t=-3.09、-2.88,P均＜0.05,n =7 ～8）.3.cGMP可被PDE分解为5＇-鸟苷酸（5＇-GMP）,因此5＇-GMP代表了PDE的活性.经50 μmol及300 μmol H2S孵育后的组织中,其5＇-GMP水平分别降至（0.25±0.06） mol/L和（0.27±0.07） mol/L,显著低于其基础值[（0.52±0.06） mol/L]（t=3.21、2.58,P均＜0.05,n=7 ～8）.结论H2S的血管舒张效应可能与其抑制大鼠PDE的活性、升高cGMP水平有关.

Obgective To observe the effect of hydrogen sulfide （H2S） on vasorelaxation and expression of guanosine 3＇,5＇-cyclic phosphate （cGMP） and activity of cyclic nucleotide phosphodiesterase （PDE） in vascular tissue.Methods H2S donor was provided by sodium bisulfide sodium hydrosulfide.The isolated perfused rat thoracic aorta rings were used to test the relaxation responses to H2S,which recorded by Power Lab system,and the enzyme linked immuno assay was used to detect intracellular cGMP.The activity of PDE was evaluated by using cyclic nucleotide PDE assay kit.Results （1） H2S relaxed the thoracic aorta rings,and the half maximal effective concentration （EC50） for the H2 S relaxation curve,represented by the corresponding concentration of H2 S that achieved 50% of the maximum relaxation effect,was （1.79 ± 0.31） ＆#215; 10-5 mol/L.（2）The cGMP content in vascular tissue increased from （22.29 ± 1.59） pmol/L to（41.45 ± 7.49） pmol/L and （31.35 ± 2.56） pmol/L after incubation with 50 μmol/L and 300 μmol/L H2 S,respectively （t =-3.09,t =-2.88;all P 〈 0.05,n =7-8）.（3） cGMP could be lysed into 5＇-guanylicacid（5＇-GMP） by PDE,which was an important pathway for cGMP degradation.This study showed that PDE activity was decreased in vascular tissue,the 5＇-GMP decreased from （0.52 ±0.06） mol/L to （0.25 ±0.06） mol/Land （0.27 ±0.07） mol/L after incubation with 50 μmol/L and 300 μ mol/L H2S,respectively （t =3.21,t =2.58;all P 〈 0.05,n =7-8）.Conclusion The vasorelaxant effects of H2 S might be related to the inhibited activity of PDE and elevated content of cGMP.