The Effect Of Adiponectin On Myocardial Injury In Asphyxia Of Neonatal Rats And Its Mechanism

Objectives：1. To observ myocardial enzymes (CK, LDH) change, myocardial injury andmyocardial apoptosis in neonatal rates after asphyxia by establishing the model ofneonatal rates with normopbaric asphyxia.2. To study the existence of the activation of AMPK pathway in hypoxic-ischemic heart of neonatal rates after asphyxia.3. To study the effect of Adiponection on myocardial injury and the expressionof myocardial AMPK protein in neonatal rates after asphyxia,and to explore itspossible mechanism.Methods:1. Grouping：Totally50newborn Sprague-Dawley(SD) rats of seven day-old wererandomly divided into5groups (n=10in each group):sham-operated group、asphyxiagroup、adiponectin group(APN group)、Compound C group、APN+Compound Cgroup.2. Model building and intervention:Establishing the model of neonatal rats withnormobaric asphyxia in other four groups(asphyxia group、APN group、Compound Cgroup、APN+Compound C group),but only simulate the process of the model ofneonatal rats with normobaric asphyxia in sham-operated group,do not plug stopperand reoxyg enation;120μg/kg recombinant human adiponectin was intraperitoneallyinjected to the rats of APN group and APN+Compound C group half hour beforestablishing the model,20mg/kg Compound C was intraperitoneally injected to therats of Compound C group and APN+Compound C group1hour befor establishingthe model;the rats of other two groups received the same dose of normal saline(0.9%).Then the blood and myocardial tissue samples were immediately obtained afterreoxyg enation, which were used for the detection of relevant index.3.Detect the level of serum myocardial enzymes CK and LDH;the pathologicalchanges of myocardium were observed under optical microscope after HE staining; the expression of myocardial AMPK were measured by immunohistochemicalstaining.Myocardial apoptosis were investigated both qualitatively and quantitativelyby TUNEL method;4. Statistical methods:using the software of SPSS19.0for statistical analysis, allthe datas were expressed as mean±standard error(x±ｓ), and statistical significancebetween groups was evaluated by One-Way ANOVA, and carried on F test,themultiple comparison was evaluated by SNK-q test, P<0.05represented the differencehad statistics meaning, P<0.01represented the difference is significant.Results:1. The levels of serum myocardial enzyme CK and LDH: Compared withsham-operated group,the level of CK and LDH rised significantly in sphyxiagroup(P<0.01);Compared with asphyxia group,it decreased significantly in APNgroup(P<0.01),but rised significantly in Compound C group and APN+Compound Cgroup(P<0.01);And the levels of serum myocardial enzyme CK and LDH in APN+Compound C group was lower than in Compound C group,and the differences wassignificantly(P<0.01).2. The pathological changes of myocardium:Myocardial cells were arrangeduniformly,no edema,the structure is complete,no infiltration of inflammatorycells,cytoplasm were slight-stained and distributed evenly,dense nuclei were clearlyvisible in sham-operated group;While in asphyxia group,Compound C group,APN+Compound C group,such changes could be observed:myocardial cells were disorderlyarranged and markedly edematous,a large number of inflammatory cellsinfiltrating,scattered necrotic cells could be seen,nuclei were disappear andvacuolated.Interstitial hemorrhage and necrosis were not obvious,and inflammatorycells decreased in APN group.3. The expressions of myocardial AMPK protein:Compared with sham-operatedgroup,the expressions of myocardial AMPK protein increased in asphyxia groups(P<0.01);Compared with asphyxia group,it rised significantly in APNgroup(P<0.01),but decreased significantly in Compound C group (P<0.01);Compared with Compound C group,the expressions of myocardial AMPK proteinrised in APN+Compound C group,and the differences was significantly(P<0.01). 4. Myocardial apoptosis marked by fluorescence:Observed under fluorescencemicroscope,sham-operated group only a small amount of normal apoptoticcell,apoptotic cells significantly increased in asphyxia group、Compound C group andAPN+Compound C group,apoptotic cells in APN group was less than that theprevious three groups,but more than that in sham-operated group.5. Results and analysis of myocardial apoptotic index (AI):Compared withsham-operated group,the AI increased significantly in asphyxia groups(P<0.01);Compared with asphyxia group,it idecreased significantly in APN group,but risedsignificantly in Compound C group (P<0.01);Compared with Compound C group，the AI idecreased significantly in APN+Compound C group (P<0.01).Conclusions:1. Adiponection can decrease myocardial apoptosis,that play a protective effecton hypoxic-ischemic heart of neonatal rats after asphyxia.2. There exist the activation of AMPK signal molecule in hypoxic-ischemicheart of neonatal rats after asphyxia.3. Adiponection play a protective effect on hypoxic-ischemic heart of neonatalrats after asphyxia by activating AMPK signal pathway.4. AMPK inhibitor Compound C can abolish those myocardial protective effectsof adiponectin.