窒息死大鼠脑组织iNOS的表达及法医学意义

发布时间：2018-06-24 08:29

本文选题：窒息 + iNOS　；参考：《重庆医科大学》2008年硕士论文

【摘要】： 背景及目的:机械性窒息死是凶杀案件中最多见的死因之一,大多数案件可通过现场勘验、尸体内外部征像可确定机械性窒息死。但少数案件现场遭受破坏或痕迹不清,尸体内外部无特异征象,难以判定为机械性窒息死。根据机械性窒息的机制,脑是受到损伤最为严重的内部器官,且死后脑组织完整不易受到破坏。检测某些物质在机械性窒息死脑组织中的特异性变化,为推断机械性窒息死提供一定科学依据。 iNOS是一氧化氮合酶的一种亚型,在生理状态下不表达或微量表达;当机体受到炎症、缺血缺氧、损伤、紫外线等刺激后,能在相应病变的组织或器官大量表达,并呈一定的时间规律性。本实验主要研究大鼠窒息死组与其它死亡组脑组织中iNOS的表达规律,并探讨其在机械性窒息死因推断上的法医学意义。方法:1、动物模型:实验动物来源于重庆医科大学动物实验中心饲养的健康清洁的SD大鼠80只,按照随机的原则将大鼠分为机械性窒息死亡组、失血性休克死亡组、脑挫裂伤死亡组及断颈死亡组。大鼠颈部放入尼龙绳的活套内,背对活结,依靠大鼠自身重量使活套拉紧,造成颈部压迫窒息死亡模型;用10g砝码从20CM高度,在导管内自由落体垂直打击硬脑膜,建立脑挫裂伤死亡模型;分离出双侧颈动脉,剪断放血至休克死亡模型;用一手拇指和食指用力往下按住鼠头,另一只手抓住鼠尾,用力向后上方拉动,造成脊髓横断致断颈死亡模型;2、取材:在各组死后不同时间点在大脑中部作横切面切取0.4CM脑组织;3、对所取材脑组织石蜡切片进行HE染色光镜观察;4、采用免疫组织化学染色法进行iNOS染色;5、使用SPSS 13.0软件包对所得数据进行统计学分析。结果:各组0h的染色和同组各时段相比阳性染色稍底,同一组染色结果在(6h、12h、24h)各时间点上没有显著染色差别,机械性窒息死亡组在大脑灰质神经元胞浆内染色深,呈明显棕黄色,基本上累及整个视野所有神经元的胞浆与失血性休克死亡组和脑挫裂伤死亡组及断颈死亡组有显著染色差别;失血性休克死亡组和脑挫裂伤死亡组神经元胞浆内染色较深,在整个视野中大部分的神经元胞浆受累及,两组间无明显染色差别;断颈处死亡组未见明显染色,偶见个别神经元胞浆内有浅谈染色。结论:大鼠机械性窒息死后iNOS特异性的高表达具有一定的规律性,死后6h、12h、24h,iNOS的表达趋于同一水平且都比死后0h,iNOS表达水平高。机械性窒息死后各时间点iNOS表达水平明显高于其它各死亡组死后各时间点iNOS表达水平。因此,iNOS可作为法医学者诊断窒息死的一个辅助指标。
[Abstract]:BACKGROUND & OBJECTIVE : Mechanical asphyxiation is one of the most common causes of death . Most of the cases can be found to be mechanically asphyxiated . However , few cases are damaged or traces are not clear . There is no specific sign inside the body , and it is difficult to determine the mechanical asphyxia death . According to the mechanism of mechanical asphyxia , the brain is the most serious internal organ , and the brain tissue is not damaged after death .

iNOS is a subtype of nitric oxide synthase , which is not expressed or micro - expressed in physiological state . When the organism is stimulated by inflammation , ischemia , hypoxia , injury , ultraviolet , etc . , it can be expressed in the tissues or organs of the corresponding lesion , and has a certain time regularity . This experiment mainly studies the expression of iNOS in the brain tissue of asphyxiated rats and other dead groups , and discusses its forensic significance in the inference of mechanical asphyxiation .

Methods : 1 . Animal model : Eighty healthy SD rats were randomly divided into mechanical asphyxia death group , hemorrhagic shock death group , brain contusion and death group and neck fracture death group .

Results : The staining of each group 0h was slightly different from the positive staining at all time points in the same group . There was no significant difference in the staining results at all time points ( 6 h , 12 h , 24 h ) .

Conclusion : The high expression of iNOS after mechanical asphyxia in rats has a certain regularity , and the expression of iNOS tends to be at the same level at 6h , 12h , 24h and 24h after death . The expression level of iNOS is higher than that at 0h after death . The level of iNOS expression in various time points after mechanical asphyxia is obviously higher than that of other dead groups after death . Therefore , iNOS can be used as an auxiliary index for the diagnosis of asphyxia death by forensic medicine .
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2008
【分类号】：D919

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