Content Variation Of Heart-type Fatty Acid Binding Protein(H-FABP) Of Early Myocardial Injury And Necrosis In Rats

Purpose:On the basis of the induction of acute myocardial injury and necrosis,todetect the change of concentration of serum heart-type fatty acid bindingprotein(H-FABP) in rats at different points in time,and explore the value of H-FABPfor early diagnosis in the event of Acute Myocardial Infarction(AMI) by comparingwith the change of cardiac troponin I(cTnI).Method: Male Sprauge Dawley rats (200±20g) were induced of acute myocardialinjury and necrosis by the way of multipoint subcutaneous injection of isoproterenol10mg/kg,once every24hours,continuously for3days.Control group received theinjection of normal saline(NS)10mg/kg the same volume as model group.MaleSprauge Dawley rats were divided into the model group(n=20) and controlgroup(n=10) at random.Operating steps were as follows:All the animals had beentaken absolute diet and water for4hours before the operation.After weights wererecorded,each group received intraperitoneal(IP) injection by using pentobarbitalsodium3ml/kg for anesthesia.Then the animal was fixed on the operating table whenits muscle tension weakened.Opened the RM6240multi-channel physiological signalacquisition and processing system and set up parameters.Inserted pins into hypodermof arms and legs,then connected positive pole(red) to left arm,negative pole(green) toright arm,and reference pole(black) to right leg,and recorded ECG II.Afterendotracheal intubation and carotid artery separation were operated,observed thebaseline of ECG,when it stabled the ECG was recorded.Gave multiplant subcutaneousinjection of isoproterenol10mg/kg last time the next step,observe the change of ECGwaves at the same time,and kept the records of ECG waves at different points in time.The standard was taken from the change of J point.Collected blood0.5ml fromcommon carotid artery at the time1h,3h,6h,and8h after the last injection,respectively.Centrifuged the blood sample,extracted the supernatant,thensub-packaged and marked it and brought it to-80℃refrigerator instantly forcryopreservation. Control group received the injection of normal saline(NS)10mg/kgthe same volume as model group.And all the operations were the same as modelgroup.Our study was to measure the concentration of blood H-FABP and cTnI byusing enzyme-linked immune sorbent assay(ELISA) to compare the differences of thevariation of H-FABP and cTnI between model group and control group.Result:1.Animals survival condition:4rats were died during the induction,whichmeans the mortality is13.33%.These rats died from bleeding,asphyxia because ofairway blockage, ventricular fibrillation,and overdose of anesthetic respectively.2.Pathological examination:Myocardial pathological section of model group showedthat myocardial eosinophil was more strengthened than that of controlgroup.Furthermore,model group also showed myocardial fiber swelling,degenerationand breakage,and dilatating and congesting vessels.It also could be seen that thephenomenon of nuclear fragmentation and karyolysis,even spotty and patchy necrosisin the cardiomyocytes,and inflammatory cells in mesenchyme.3.ECG examination:All the ECGs recorded from model group showed ischemia orinfarction graph,such as the change of J point and T wave,and the formation of Qwave in part.4.Comparison of serum levels of cTnI in each group: Comparison of differentpoints in time in the same group: the control group at each time point was nosignificant difference (P>0.05).In model group,the difference between the group atthe time1h and3h was without significant difference(P>0.05).However,there wassignificant difference between the group at the time6h and1h,8h and1h(P<0.01).Comparison of different points in time between model and control group:there wassignificant difference between model and control group in addition to the time1h and3h(P<0.01). 5.Comparison of serum levels of H-FABP in each group: Comparison of differentpoints in time in the same group: in control group, the difference between the group atthe time1h and3h was without significant difference(P>0.05), However,there wassignificant difference between the group at the time6h and1h,8h and1h(P<0.01).There is significant difference in control group at each time point(P<0.01).Comparison of different points in time between model and control group:there wassignificant difference between model and control group in addition to the time1h and3h(P<0.01).Conclusion:1.During the induction of acute myocardial injury and necrosis,serum levels of cTnIdoesn’t increase in3hours since the last injection,while H-FABP does,earlier thancTnI.2.H-FABP can be considered as an early diagnosis indicator for using isoproterenolfor the induction of myocardial infarction in rats.