| Background:TNF-αis one important cytokine possessed extensive biological activities and researched by many scholars recently. TNF-αparticipates in many pathological course include myocytes death or the function of heart disorder. Originally, people think it produced by mononuclear phagocytes in blood and different tissues. Current data indicate that adult myocytes can also produce TNF-αin the course of various heart disease, such as congestive heart failure, myocarditis, ischemic heart disease, dilated cardiomyopathy, and septic cardiomyopathy. Elevated TNF-αis considered to be contributive to the pathophysiology of these diease.ICAM-1 is a glycoprotein to exist the surface of cells and mediates leucocytes to adhere to other cells or extracellular matrix. It play an important role in inflammation and immune reaction through adhere to the substance of surface in various cells include cardiac myocytes. Some cytokine especially TNF-αcan promote the expression of ICAM-1.Objective: To study the expressions of TNF-αand ICAM-1 in heart through establish a model of stress in mice, we explored the mechanism of these two factors in myocardium injury. The regularity maybe contribute to evaluate the degree of myocardium injury in stress for forensic identification and clinical treatment.Methods: We established a model of myocardium lesion by injecting ISO to the enterocoelia of mice, the dose of ISO is 30mg·kg-1·d-1. 160 mice were randomly divided into normal control and stress groups. The injury groups were then subdivided into 1t, 2t, 3t, 4t, 5t groups according to the stress times; then each stress group was subdivided into 12h, 1d, 2d, 3d, 4d groups according to the time elapsed after stress, the additional groups after 15min,30min,60min,2h,4h,6h by stress were set up among the 1t group. Mice in each group were to put to death when the stress time elapsed. To obtain the heart of mice immediately, then this tissue has been prepared by paraffin section for HE staining and immunohistochemical staining with antibodies against TNF-α, ICAM-1. The staining results have been observed with light microscopy and analyzed by image processing system.Results: 1.histopathologic studies: We observed the typical pathological characteristic were degeneration, necrosis and the fusion of focal degeneration in myocardium partly. These lesion include swelling, fragmentation, lysis, inflammation cells infiltration and interstitialconnective tissue proliferation, fibroblast proliferation; 2. Ultrastructure studies: It displaied the quantity of mitochondrion and lipid droplet increased,the chromatin of VEC and fibroblast assembled on the verge of nucleus, cardiac myocyte apoptosis, and myofilament rarefaction, lysis, rupture and the structure of sarcomere were incomplete, in addition, We also observed there were increased myeloid structure in myocardium; 3. immunohistochemical studies: ①There were little positive substance of TNF-αand ICAM-1 expressed in heart in normal control; ②The expression of TNF-αwas more obvious than ICAM-1 in the earlier period after stress, and the site of them were approach to endocardium; ③The positive substance of TNF-αand ICAM-1 were increased significantly after stress; ④Before stress 3 days , the expression of TNF-αincreased less than ICAM-1, oppositely , after stress 3 days, the expression of TNF-αincreased more than ICAM-1; ⑤TNF-αexceed ICAM-1 in the amount of expression as a whole; ⑥The expression of TNF-αget the peak as well as ICAM-1; ⑦The expression of TNF-αand ICAM-1 decreased gradually when stress to end.Conclusion: The expression of TNF-αand ICAM-1 increased in stress indicated these factors participated in the process of myocardium injury, but the regularity of TNF-αwere not consistent with ICAM-1 completely, it hint TNF-αand ICAM-1 have different effect in myocardium injury in stress. Meanwhile, their changes along with timehave some regularity, so it may be an objective markers to applied to evaluation of myocardium injury...
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