| Objective: The purpose of this research is to study the effect of Levosimendan in post-resuscitation intestinal microcirculation in SD rats with cardiac arrest induced by ventricular fibrillation.And investigate the different mechanisms of two subtypes of ATP sensitive potassium channel in protecting post-resuscitation intestinal microcirculation.Methods: SD rat models of ventricular fibrillation induced cardiac arrestresuscitation were established and randomly divided into five groups: 1)shame group(SHA group,n=5);2)cardiac arrest-resuscitation control group(CON group,n=10);3)nonselective KATP channel opener Levosimendan group(LEV group,n=10);4)selective sarc KATP channel blocker HMR-1098 group(HMR group,n=10);5)selective mito KATP channel blocker 5-HD(5HD,n=10).1.Sidestream dark field(SDF)was used to detect the total vessel density(TVD),perfused vessel density(PVD),proportion of perfused vessels(PPV),microvascular flow index(MFI)to evaluate the intestinal microcirculation of each group at baseline(BL),one hour(1 H),two hour(2 H),three hour(3 H),four hour(4 H),five hour(5 H),six hour(6 H).2.Blood samples were detected the content of serum interleukin-1(IL-1),interleukin-6(IL-6),interleukin-10(IL-10),tumor necrosis factor-α(TNF-α)and lactic acid(Lac)at BL,1 H,4 H,6 H.3.After 6 H,the rats were sacrificed,and the small intestine and blood samples were removed for detection of the intestinal water content,pathological injury,the expression of signaling pathway related genes and proteins(PI3K-Akt-e NOS-NOc GMP-PKG),apoptosis related genes and proteins(Bcl-2,Bax,caspase-3).Results:Part 1 No significance was observed in baseline data of microcirculation indicators(TVD,PVD,PPV,MFI)and inflammatory markers(IL-1,IL-6,TNF-a,IL-10)in all groups(P>0.05).After cardiac arrest-resuscitation,microcirculation indicators decreased significantly,especially at 1 H after resuscitation(p<0.05)in CON group.Comparing with CON group,there was a dramatically increased of microcirculation indicators(p<0.05)in LEV group.HMR group indicators almost had no differences than LEV group(p>0.05),while 5HD group showed block results(p<0.05).After cardiac arrest-resuscitation,inflammatory markers(IL-1,IL-6,TNF-a)increased significantly(p<0.05),inflammatory markers(IL-10)decreased largely(p<0.05)in CON group.Comparing with CON group,there was a dramatically diminished of IL-1,IL-6,TNF-a(p<0.05)in LEV group,and increased of IL-10(p<0.05).HMR group markers almost had no significance than LEV group(p>0.05),while 5HD group showed opposite results(p<0.05).HMR group indicators almost had no differences than LEV group(p>0.05),while 5HD group showed block results(p<0.05).After resuscitation,Comparing with CON group,pathological injury score(Chiu’s score),water content and levels of Lac of intestinal tissues obviously lower in SHA group(p<0.05)and LEV group(p<0.05).HMR group score nearly same with LEV group(p>0.05),but 5HD group present block results(p<0.05).Part 2signaling pathway:The genes expression of PI3 K was slightly increased in the CON group with resuscitation(p=0.54).Comparing with CON group,the expression of PI3 K was significantly increased in LEV group(p<0.05).The expression in HMR group almost same with LEV group(p=0.80),but 5HD group present block results(p<0.05).The genes expression of Akt was obviously decreased in the CON group after resuscitation(p<0.05).Comparing with CON group,the expression was significantly increased in LEV group(p<0.05).The expression in HMR group almost same with LEV group(p=0.80),but 5HD group present block results(p<0.05).No difference was observed in Akt expression in HMR group and LEV group(p=0.40),but a big difference was observed in 5HD group and LEV group(p<0.05).The genes expression of e NOS and PKG were obviously decreased in the CON group after resuscitation(p<0.05,p<0.05).Comparing with CON group,the expression of e NOS and PKG were significantly increased in LEV group(p<0.05,p<0.05).The expression of e NOS and PKG in HMR group almost same with LEV group(p=0.47,p=0.99),but 5HD group present block results(p<0.05,p<0.05).The proteins expression of PI3 K,p-PI3 K,Akt,e NOS,p-e NOS were no differences between the SHA group and CON group(p>0.05),but,the p-Akt expression was decreased significantly in CON group(p<0.05).The proteins expression of PI3 K,Akt,e NOS were no differences among the LEV group,HMR group and 5HD group(p>0.05),while,the p-PI3 K,p-Akt,p-e NOS expression were increased significantly in LEV group(p<0.05).The p-PI3 K,p-Akt,p-e NOS expression in HMR group had no significance with LEV group(p>0.05),but 5HD group present opposite results(p<0.05).Apoptosis:The genes expression of Bcl-2 and Bax were significantly increased in the CON group after resuscitation(p<0.05,p<0.05).Comparing with CON group,the expression of Bcl-2 was increased in LEV group(p<0.05).The expression of Bcl-2and Bax in HMR group almost same with LEV group(p=0.21,p=0.88),but 5HD group present block outcomes(p<0.05,p<0.05).Comparing with CON group,the expression of Bax was decreased in LEV group(p<0.05).The gene expression of Casepase-3 in five group had no significantly different(p>0.05).The proteins expression of Bcl-2 and Casepase-3 were no differences among the five groups(p>0.05),but,the p-Bcl-2,Bax and A-Casepase-3 expression were increased significantly in CON group(p<0.05,p<0.05,p<0.05).The proteins expression of p-Bcl-2 were increased significantly in LEV group(p<0.05),but Bax and A-Casepase-3 decreased(p<0.05,p<0.05).The p-Bcl-2,Bax and A-Casepase-3expression in HMR group had no differences with LEV group(p>0.05,p>0.05,p>0.05),but 5HD group present opposite comes(p<0.05,p<0.05,p<0.05).Conclusions: Levosimendan plays a protective role in intestinal microcirculation and pathological injury in SD rat models with cardiac arrest induced by ventricular fibrillation.The positive protection may be activated by mito KATP channel signaling pathway(PI3K-Akt-e NOS-NO-c GMP-PKG).The protective function of Levosimendan is also involved in the regulation of systemic inflammatory response and apoptosis after cardiopulmonary resuscitation. |
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