【作者】 田甜；

【导师】 邓世雄；

【作者基本信息】 重庆医科大学 ， 法医学， 2003， 硕士

【摘要】 背景及目的： TNF-α是近年来研究较为活跃的细胞因子，具有广泛的生物学活性，在心脏的多种病理过程中可导致心肌细胞死亡或心脏功能障碍。TNF-α主要由巨噬细胞产生，但在一定条件下，心肌细胞也可产生TNF-α； ICAM-1是介导白细胞与不同起源的细胞或细胞外基质粘附的一种细胞表面糖蛋白，在炎症及免疫反应中起重要作用。ICAM-1可与包括心肌细胞在内的多种细胞表面成分结合，分布十分广泛。一些细胞因子可促进ICAM-1表达，其中TNF-α的作用尤其引人注目。本实验建立小鼠应激性心肌损伤模型，对TNF-α及ICAM-1在心脏中的表达规律进行研究，探讨二者在应激性心肌损伤中的作用及心肌应激性损伤的机制，为应激性心肌损伤的法医学鉴定及临床治疗提供科学依据。方法：取ISO以30mg·kg-1·d-1剂量腹腔注射，每24小时一次，建立小鼠应激性心肌损伤模型。按应激次数划分为5组，即应激1t、2t、3t、4t、5t。每一组又根据应激后处死动物时间不同分为应激后12h、1d、2d、3d、4d等5组，其中应激1t组增设应激后15min、30min、60min、2h、4h、6h组；另设一个对照组。各组动物达预定时限后立即取出心脏，对心肌组织进行HE、超微结构及TNF-α、ICAM-1免疫组化染色，并对染色结果进行光镜、超微结构观察和图像分析，以了解TNF-α和ICAM-1在应激早期及其后的持续应激中的表达及应激对心肌的损伤情况。<WP=6>结果：1.组织病理学观察：典型的病理表现为心肌局灶性变性、坏死（肌浆凝聚、肌浆溶解）和灶性病变融合。损害包括心肌纤维肿胀、断裂、溶解，炎性细胞（中性粒细胞和单核细胞为主）浸润，间质纤维结缔组织增生，成纤维细胞增生；2.超微结构观察：应激早期主要表现为线粒体及脂滴数量增多，VEC及成纤维细胞核染色质边集，心肌细胞凋亡等，其后的持续应激主要表现为心肌坏死，肌丝稀疏、溶解、断裂，肌节结构不完整，有较多髓样结构形成；3.免疫组化观察：①正常对照组心肌有低水平的TNF-α、ICAM-1表达；②在应激后早期，TNF-α表达较ICAM-1显著，且其表达部位均以于近心内膜处明显；③应激后TNF-α、ICAM-1表达明显增加，且均随应激强度增大而增加；④在应激3t之前TNF-α表达量的增加较ICAM-1平缓，在应激3t之后TNF-α表达量的增加较ICAM-1陡峭；⑤TNF-α表达量在总体上高于ICAM-1；⑥TNF-α、ICAM-1均于应激后12h达高峰；⑦应激停止后TNF-α、ICAM-1的表达量均逐渐递减。结论：TNF-α、ICAM-1表达增加说明其可能参与应激性心肌损伤过程，但二者表达变化并非完全平行，说明其在应激性心肌损伤中的作用不尽相同。同时，二者的表达变化具有一定的时间规律，据此可望作为一种客观指标应用于法医学应激性心肌损伤的评判，并为临床治疗提供依据。更多还原

【Abstract】 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.<WP=8>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 interstitial<WP=9>connective 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 time<WP=10>have some regularity, so it may be an objective markers to applied to evaluation of myocardium injury更多还原