The Experimental Study Of Heart-type Fatty Acid Binding-protein In Postmortem Diagnosis Of Acute Myocardial Infarction

Objective To observe the changes of H-FABP in the heart cells, blood in heart and femoral vein(peripheral blood) of normal rats and rats with acute myocardial infarction in different postmortem intervals and to study the affection of autolysis to concentration of H-FABP in order to provide basis for postmortem diagnosis of AMI.Methods Animal model of AMI was produced by ligating rat's left anterior descending coronary artery (LAD). Briefly, 66 SD rats weighting 200~300g of either sex were randomly distributed into 11 groups including 1 sham-operated group (group D) , 5 control groups(A1, A2, A3, A4, A5) and 5 study groups (B1, B2, B3, B4, B5). In sham-operated group, rats were killed at 4h after sham operation. In control groups, blood samples and animal hearts were collected at 0h, 6h, 12h, 24h and 48h after death. In study groups, rats were killed at 4h after ligating its LAD and blood samples and animal hearts were collected at 0h, 6h, 12h, 24h and 48h after death. The concentrations of H-FABP in myocardial cells in various postmortem intervals were observed by imrnunohistochemical staining. Postmortem serum concentrations of H-FABP in myocardial blood and peripheral blood in different intervals were observed by enzyme-linked immuno-sorbent assay.Results1. Imrnunohistochemical staining: (1) In normal control group of Oh, cytoplasm of all cardiomyocytes were stained homogeneous brown after counterstaining with hematoxylin, the nuclei were stained light blue, matrix and other cells were not stained. The heart tissue became autolysis with the prolonging of postmortem intervals. At 48h after death, the binds among cells were indistinct, strait in heart cell was disappeared, the nuclei broke, dissolved, disappeared and heart tissue appeared brown. (2) In study groups of Oh, the complete depletion of H-FABP from cardiomyocytes in ischemic areas started and the difference was significant compared with normal control group of Oh. Autolysis happened in every postmortem interval, membrane of cells became incomplete, the binds among cells were indistinct, nuclei broke, dissolved, disappeared. After 48 hours, all cardiomyocytes were stained homogeneous brown, it was difficult to distinguish normal area and AMI area andthe difference was not significant compared with control groups.2. Enzyme-linked immuno-sorbent assay: (1) In both study groups and control groups, the concentrations of H-FABP in heart blood were higher than the one in peripheral blood and four time-concentration cure rose with the postmortem time. (2) The comparision of H-FABP concentrations in peripheral blood between two groups: In 0 hour study group, the FABP concentration in peripheral blood was 462.71±214.44Mg/l,the H-FABP concentration in heart blood was 64.57±14.27Hg/l, study group was obviously higher than control group. With the prolonging of postmortem time, the concentrations of H-FABP in control groups rose rapidly, but the difference was not significant. (3) The comparision of H-FABP concentrations in heart blood between two groups: In Oh, 6h intervals, the concentrations of H-FABP in study group were 1665.23±452.00 and 2180.21±802.34H-g/l, the one in control group were741.48±158.34and 1323.81±373.50H-g/l, the former was higher than the later and the difference was significant. After 6h, the concentration in control group rose, but was still lower than the one in study group and the difference was unobvious. (4) The heart blood concentration of H-FABP in study group was higher than the one in sham-operated group (96.10±40.39Hg/l), the peripheral blood concentration of H-FABP in study group was higher than the one in sham-operated group (57.3^30.58^/1), while the difference was significant.Conclusions (1) Peripheral blood concentrations of H-FABP in normal rats and rats with AMI rose obviously because of autolysis, the two groups had no difference, so peripheral and myocardial blood concentrations of H-FABP cannot be used in diagnosis of early acute myocardial infarction. (2) Immunohistochemical staining of H-FABP in two groups was affected by autolysis with the prolong of postmortem time, both appeared homogeneous brown and had no difference, it was difficult to distinguish infarction area, so immunohistochemical staining of H-FABP cannot be used in postmortem diagnosis of early acute myocardial infarction.