RESUMO
Objective To observe the members' dynamic change of renin-angiotensin system (RAS) and angiotensin converting enzyme 2(ACE2)-Ang(1-7)-Mas axis during the continuous venovenous hemodiafiltration (CVVHDF) treating the dogs with multiple organ dysfunction syndrome (MODS),and to investigate the efficacy mechanism on cardiac function.Methods Dogs were subjected to hemorrhagic shock plus resuscitation and endotoxemia to establish MODS model,then they were randomly divided into 2 groups:CVVHDF group (n=8) and MODS group (n=6).After endotoxin injection completion,the CVVHDF group received CVVHDF for 12 h,MODS group didn't.Radioimmunoassay,euzymelinked mmunosorbent assay (ELISA) were used to detect the content of renin,Ang Ⅰ,Ang Ⅱ,Ang (1-7).Real-time PCR was used to detect the expression of renin mRNA and ACE2 mRNA.Western blotting was used to detect the protein content of renin,Ang Ⅱ,ACE2 and Ang (1-7).Results (1) Organ function:Compared with the MODS group,the vital signs,heart,lung and renal function were significantly ameliorated in the CVVHDF group,the difference had statistical significance (P＜ 0.05).(2) RAS changes:To detect index from the level of organs,genetic and molecular in arterial tissue,the results displayed that the content of renin,Ang Ⅰ,Ang Ⅱ,the expression of renin mRNA,the protein content of renin,Ang Ⅱ in CVVHDF group were lower than that in MODS group,the difference had statistical significance (P ＜ 0.01).(3)ACE2-Ang(1-7)-Mas axis's changes:Using the same methods above to detect corresponding indicators,the results displayed that the content of ACE2,Ang(1-7),the expression of ACE2 mRNA and the protein content of ACE2,Ang(1-7) in CVVHDF group were significantly improved than that in MODS group,the difference had statistical significance (P ＜ 0.01).Conclusions In the process of CVVHDF treating MODS,the ACE2 -Ang(1-7)-Mas axis plays the role which antagonizes the RAS system,and to protect the cardiac function.This research may be important for MODS' clinical rescue.