Synergistic Effect Of Hydrogen Sulfide And Nitric Oxide On Rat Hemody Namics And Its Related Mechanism

Objective: To investigate the hemodynamics in rats treated with hydrogen sulfide(H2S) donor sodium hydrosulfide(Na HS) and(or) nitric oxide donor sodium nitroprusside(SNP). Methods: A total of 40 male wistar rats were randomly divided into four groups and given normal saline, Na HS, SNP, Na HS+SNP, respectively. Mean arterial blood pressure(MAP) and heart rate(HR) were recorded at 5 min, 10 min, 30 min, and 60 min after Na HS or SNP treatment. Spectrophotometry was performed to measure rat plasma H2 S and NO content at 60 min. Western blot was performed to measure rat CSE protein expression in thoracic aorta at 60 min. In Na HS+SNP treatment group, CSE enzyme blocker PPG or NOS enzyme blocker L-NAME were injected intravenously to study the specific mechanisms of synergistic effect. Results: Treatment with Na HS or SNP alone did not change rat MAP or HR significantly. Treantment with Na HS and SNP decreased MAP and HR, which were significantly lower than those in the control group as well as in Na HS or SNP group(P<0.05). Given with Na HS or SNP alone elevated H2 S and NO content in rat plasma, respectively, moreover, SNP can also elevate plasma H2 S content. Combined administration with Na HS an SNP can increase rat plasma H2 S and NO content significant. When given alone, or combined with Na HS, SNP can increase the CSE protein expression in rats aorta tissue. In the combined treatment group, the CSE inhibitor PPG can increase MAP significantly, while NOS inhibitor L-NAME had no effect on MAP. Conclusion: HS and NO have a synergistic effect on reducing MAP and HR in Conclusion: H2 S and NO have a synergistic effect on reducing MAP and HR in normal rats. NO can enhance the blood pressure lowering effect of H2 S, and the underlying mechanism is related with the enhanced expression of CSE protein in vascular smooth muscle tissue.