大鼠急性脑干损伤致死后脑干组织细胞色素C含量的测定

目的探讨细胞色素C含量测定在脑干损伤死后诊断中的意义。方法采用重物自由落体造成的大鼠急性脑干损伤模型,通过酶联免疫(ELISA)的方法,检测脑干损伤致死大鼠与非脑干损伤致死大鼠脑干组织细胞胞浆细胞色素C含量。结果急性脑干损伤组神经元细胞胞浆细胞色素C的含量(8.276±0.425)较非脑干损伤组(2.002±0.514)为高,其差异具有显著性意义(P<0.05)。结论脑干组织细胞色素C含量测定对急性脑干损伤的死后诊断具有参考价值。     

大鼠双后肢挤压伤后肺、肝细胞的凋亡

目的研究大鼠双后肢挤压伤后肺、肝细胞的凋亡过程,探讨挤压伤损伤机制。方法建立大鼠双后肢挤压伤模型,采用TUNEL法对大鼠肺、肝细胞凋亡进行检测,免疫组织化学法检测凋亡相关蛋白Bax、Bcl-2、caspase-3的表达。结果与对照组相比,损伤组大鼠双后肢局部肌肉组织明显损伤,肺、肝细胞凋亡明显增多(P0.05),凋亡相关蛋白Bax上调、Bcl-2下调、caspase-3被激活(P0.05)。结论大鼠双后肢挤压伤后引起肺、肝细胞凋亡明显增多,可能是损伤释放的相关因子介导了细胞凋亡的发生。     

甲基苯丙胺致多巴胺能神经元毒性机制的研究进展

甲基苯丙胺属于苯丙胺类中枢兴奋剂,目前其滥用趋势严重。研究表明,甲基苯丙胺对动物及人类大脑纹状体多巴胺能神经元具有毒性作用。其毒性机制包括多巴胺信号转导影响和多巴胺的氧化作用、谷氨酸介导的兴奋性毒性作用、氧化应激和细胞因子的形成、线粒体功能紊乱、神经细胞凋亡、神经胶质细胞的活化以及高热等。但甲基苯丙胺对多巴胺能神经元的毒性机制并不完全清楚,本文结合文献对此进行综述,以期为相关研究提供参考。     

乌头碱中毒大鼠心肌酶的细胞化学研究——线粒体琥珀酸脱氢酶和细胞色素C氧化酶的超微结构定位

<正> 本文用细胞化学手段,对乌头碱中毒大鼠心肌线粒体的琥珀酸脱氢酶(SDH)、细胞色素C氧化酶(CCO)作超微结构定位,在电子显微镜下直接观乌头碱中毒后SDH、CCO的定位和活性的变化,发现乌头碱抑制了心肌大多数线粒体的SDH活性,并引起心肌线粒体CCO     

MDMA对原代培养乳鼠脑皮质神经元的损伤机制

目的探讨3,4-亚甲双氧甲基安非他明(MDMA)对原代培养乳鼠脑皮质神经元的损伤机制。方法应用ATP酶测试盒法、荧光分光光度法和高效液相色谱法,分别检测神经细胞线粒体内ATP酶活性、细胞培养上清液中去甲肾上腺素(NA)和多巴胺(DA)含量;电镜下观察MDMA对神经元细胞表面和内部超微结构的组织形态学影响。结果与正常对照组同步比较,培养8d后加入MDMA后继续培养1d,MDMA(50~2000μmol/L)组显示ATP酶活性剂量依赖性降低,但在加入MDMA的细胞培养上清中未检出NA和DA,MDMA(2000μmol/L)组观察到了显著的病理组织形态学改变。结论MDMA对原代培养乳鼠脑皮质神经元有直接损伤作用,该损伤作用非NA和DA介导,与抑制ATP酶活性密切相关。     

原发性脑干损伤神经元凋亡及caspase3的表达

目的观察原发性脑干损伤（PBSI）致死者脑干神经元凋亡及caspase3的表达情况,探讨其法医学意义。方法选择法医学检案中30例确定为原发性脑干损伤致死者脑干,按伤后不同存活时间（t≤5min、5min〈t≤15min、15min〈t≤1h、1h〈t≤24h）分为4组,以5例非脑干损伤死亡者脑干为对照组;分别运用常规HE、免疫组化和TUNEL染色检测中脑、桥脑及延脑重要核团内神经元凋亡及caspase3的表达情况。结果原发性脑干损伤后15min～24h出现明显神经元细胞凋亡（23.2%～35.9%）和caspase3阳性表达（28%～54%）,并呈现随损伤时间进行性增加的趋势,与对照组有显著性差异（P〈0.01）。结论原发性脑干损伤早期即出现神经元凋亡及caspase3表达增加,并随损伤时间的延长呈进行性增加,可据此辅助诊断原发性脑干损伤死亡。     

咖啡因对乳鼠脑皮质神经元凋亡的作用

目的考察咖啡因对乳鼠脑皮质神经元凋亡的作用。方法取出生后2-3d的乳鼠脑皮质神经元,在37℃、5%CO2、100%相对湿度的培养箱中培养7d后,分别加入终浓度为300μmol/L和1 000μmol/L的盐酸咖啡因培养液,继续培养6-36h后,流式细胞仪测定细胞内钙离子浓度、线粒体膜电位和细胞凋亡率,酶标仪测定Caspase-9的活性,电镜和Hoechst 33258荧光染色观察细胞的形态学改变。结果与正常组相比较,300μmol/L和1 000μmol/L盐酸咖啡因组在给药后6h的钙离子平均荧光强度明显增强（P〈0.05）,由正常值43.13±2.02分别增加到45.28±1.16和46.92±1.99;在给药后8h的线粒体膜电位下降最明显（P〈0.05）,由正常值443.58±11.77分别下降到289.53±16.47和165.14±14.72;在给药后10h的Caspase-9活性最高（P〈0.05）,由正常值1.00±0.000分别增加到5.33±1.02和8.33±0.92;在给药后36h的细胞凋亡率明显升高（P〈0.05）,由正常值4.94±1.74分别增加到15.98±2.03和18.70±2.09;在给药后24h荧光显微镜下见典型凋亡小体。结论咖啡因对乳鼠脑皮质神经元凋亡有促进作用。     

成年小鼠氯胺酮慢性中毒后脑细胞凋亡

目的研究不同持续时间和剂量下氯胺酮慢性中毒对成年小鼠脑细胞凋亡发生的影响。方法氯胺酮按不同剂量(4、10、20、30mg/kg)每周2次于成年小鼠尾静脉注射,建立小鼠氯胺酮滥用慢性中毒模型,氯胺酮连续注射1、2、4、8、12周后处死。采用透射电镜进行细胞凋亡的定性检测,以Caspase-3免疫荧光染色法和脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling,TUNEL)定量检测凋亡细胞数,推断凋亡发生的时间,并统计分析实验结果。结果氯胺酮染毒1周后,在透射电镜下见到脑组织海马及纹状体区域有明显的神经元凋亡,并持续至8周后;染毒1周可见Caspase-3高表达,4周后呈持续低水平表达;染毒1周后可见TUNEL阳性细胞较对照组明显增加,4周时仍处于高水平表达。结论氯胺酮尾静脉注射可致成年小鼠神经元凋亡。     

Fas-L在大鼠脑液压冲击伤后的表达

目的为探讨轻型闭合性颅脑损伤的病理诊断及损伤时间推断依据。方法通过建立大鼠脑液压冲击伤模型,用免疫组化染色方法与图像分析技术分别检测大鼠轻型闭合性颅脑损伤后15,30min,1,3,6,12h,1,4,7,14d以及正常对照组与手术对照组大鼠大脑皮质、丘脑、海马等部位Fas-L的表达。结果发现伤后1hFas-L开始在大脑皮质及海马出现表达,随时间增加表达逐渐增强,伤后3hFas-L表达显著增加,伤后12h达高峰,损伤4d后Fas-L表达逐渐减弱,14d基本恢复正常。本研究证明,Fas-L介导的细胞凋亡不仅出现于脑损伤邻近,在远离损伤部位的脑组织亦有Fas-L介导的细胞凋亡发生。结论Fas-L表达可望为轻型闭合性颅脑损伤早期诊断提供依据;根据Fas-L阳性表达的变化规律可作为脑损伤时间推测的指标之一。     

海洛因诱导大脑神经元凋亡的研究

目的观察海洛因有无直接诱导培养大脑神经元凋亡的作用。方法神经元培养取自SD大鼠妊娠的胎鼠大脑皮质,培养7d后分别用不同浓度的海洛因(纯度80%)处理大脑神经元24h。用FDA法分析细胞存活率,Hoechst 33258荧光染色后观察凋亡的形态学改变,再用DNA琼脂糖凝胶电泳分析凋亡的生化特征。结果海洛因可剂量依赖性地降低神经元的存活率;荧光显微镜可见细胞核染为高亮蓝色的典型凋亡小体,其细胞核明显固缩、凝聚和断裂,且随海洛因剂量的增加,出现凋亡小体的细胞明显增多;不同浓度的海洛因处理大脑神经元,电泳图谱显示清晰的DNA梯带。结论海洛因可直接诱导大鼠大脑皮质神经元凋亡。     

大鼠乌头碱中毒心肌酶的细胞化学研究(Ⅱ)——线粒体细胞色素C氧化酶(CCO)的定位

作者通过大鼠乌头碱中毒心肌线粒体 CCO 的超微结构定位,观察到乌头碱引起 CCO 的定位紊乱。由于损害程度不同,出现三种情况:(1)CCO 失去在线粒体嵴膜和内膜上的定位,酶反应产物呈自由扩散状态,酶反应强度对照组有所增强或相似;(2)CCO 失去在线粒体嵴膜和内膜上的定位,酶反应强度较对照组明显减弱;(3)在同一线粒体中部分保持 CCO 的嵴膜、内膜定位,部分失去 CCO 在嵴膜和内膜上的定位。实验结果表明,乌头碱干扰了心肌细胞呼吸链的电子传递,抑制氧化磷酸化的正常进行,导致心肌能量代谢障碍。     

Postmortem changes in cytochrome c oxidase activity in various organs of the rat and in human heart

Cytochrome c oxidase (COX), a mitochondrial enzyme, is inactivated by cyanide or carbon monoxide (CO) intoxication. To test whether cytochrome c has potential as an indicator of these toxins in cadavers, we measured COX activity in the main organs of the rat, and in the human heart, at various times after death. Each tissue sample or organ was homogenized and the COX activity in the mitochondrial fraction was measured using ferrous cytochrome c as the substrate. COX activity was significantly higher in rat brain, heart and kidney than in lung and liver from 0 to 4 days after death. The loss of COX activity was significantly slower in the brain and heart than in the lung, liver and kidney. Most importantly, COX activity correlated with the time-since-death for each of the rat organs we tested (r2=0.70-0.95), but for the human heart (r2=0.47). It may be possible that COX activity is likely to be a useful indicator of the time-since-death, and is worth pursuing as an indicator of the tissue cyanide and CO content.     

A DNA-based approach for the forensic identification of Asiatic black bear (Ursus thibetanus) in a traditional Asian medicine

Attempts to prevent illegal trade in bile and gallbladders from Asiatic black bears, Ursus thibetanus, are hampered by difficulties associated with identifying such items. We extracted DNA from bile crystals of unknown species origin and generated partial cytochrome b (cyt b) sequences using either universal primers (positioned in conserved regions of cyt b), or primers designed on existing U. thibetanus sequences (UT). Species origin was determined by aligning resolved sequences to reference sequence data. The universal primers were unsuitable for U. thibetanus identification when multiple species templates were present in the samples. The UT primers amplified U. thibetanus DNA from all sample extracts, including those containing mixed species templates. The amplified fragment can distinguish U. thibetanus from the most closely related species, U. americanus, a distinct advantage of DNA sequencing over the methods currently used to analyze suspected U. thibetanus bile.     

线粒体DNA的研究进展及其法医学应用

线粒体DNA(mitochondrialDNA,mtDNA)是存在于细胞质内的环状DNA。它的存在早在三十多年前就有人提出。如今,关于线粒体的研究领域是生物医学中发展最快的学科之一。它的发展基于一些很基本且有趣的问题的提出,这些问题主要是关于线粒体是如何进化,如何产生能量。另外,在疾病中线粒体基因如何发生突变、细胞凋亡如何受到它的调节、以及衰老如何对线粒体DNA发生影响等问题都有待解答,而且对这些问题的探讨将会对诸如人类学、法医学以及疾病的治疗有很大的用途。     

Potential definition of the time of death from autolytic myocardial cells: a morphometric study

Morphometric methods and transmission electron microscopy were used to quantify modifications occurring in the mitochondria of dog myocardium during the first four hours of autolysis. Myocardial fragments were obtained from the outer free wall of the left ventricle, during anesthesia (control-zero) and at 15, 45, 120, and 240 min after cardiac arrest, maintaining the heart "in situ" at 22 degrees C. During the 240 min of autolysis, the main parameters evaluated showed: (a) a decrease in the number of mitochondria from 0.31 to 0.12 per micron 3 of cytoplasm. The decrease over the first 45 min reached 50% of the initial value; (b) an increase in mitochondrial volume, three times greater after the first 45 min (from 0.92 to 2.68 micron 3) and four times greater after 240 min (from 0.92 to 3.79 micron 3); (c) an increase in mitochondrial outer membrane surface area from 5.51 to 12.54 micron 2; (d) an increase in the surface area of individual mitochondria inner membrane and cristae from 27.60 to 56.96 micron 2. The progressive nature of the alterations and the difference in the numerically expressed values allow correlation with the time of somatic death. The authors emphasize the need for further studies in order to complement the present study.     

急性乙醇中毒鼠心肌电镜细胞化学观察

以胞嘧啶单核苷酸酶（CMP）作为溶酶体的细胞代学标志酶，观察急性乙醇中毒鼠心肌细胞溶酶体和线粒体被溶酶体降解的形态变化；结果显示；多数线粒体肿胀，部分外膜溶解、破损，嵴断裂、溶解、消失，被溶酶体包围、侵入，形成空泡；肌原纤维也有不同程度损伤。作者推断：急性乙醇中毒时，线粒体的病理性损伤是造成心肌和传导系功能障碍的重要原因。     

Age estimation using cytochrome c oxidase activity analysis

Recently, in the field of forensic medicine the number of unidentified cadavers has increased due to mass disasters and international terrorism. In addition to the conventional anthropological methods, a simple and precise method to estimate the age of these unidentified cadavers to assist in the personal identification is necessary. On the other hand, many researchers have reported that mitochondrial respiratory activity decreases with aging because of the production of reactive oxidative species in the process of ATP generation. Therefore, it may be possible for us to estimate human age by analyzing mitochondrial activity. In this report we attempted to analyze cytochrome c oxidase (CCO) activity, and the amount of protein and mRNA expression in various aged rats. The age of human subjects was estimated through the analysis of human CCO activity from 28 actual forensic cases. The CCO activity, the amount of protein and the mRNA expression increased in the 3rd week and decreased afterwards in rats. Furthermore, human CCO activity was decreased gradually with aging. Therefore, CCO activity analysis may be useful for age estimation in forensic cases.     

Validation of Ultrastructural Analysis of Mitochondrial Deposits in Cardiomyocytes as a Method of Detecting Early Acute Myocardial Infarction in Humans*

Abstract: In the present study, ultrastructural analysis of mitochondrial deposits (black dots within mitochondria) as a method for the detection of early acute myocardial infarction (AMI) was evaluated. In 24 patients with AMI and six controls, analysis was performed in the heart of infarcted patients and noninfarcted controls. In the infarction area in lactate dehydrogenase (LDH)‐diagnosed AMI, the percentage of positive mitochondria was significantly higher compared to corresponding heart tissue in control patients and compared to noninfarcted areas within these patients. Also in patients with a clinically diagnosed AMI but no LDH decoloration, a significant higher percentage of positive mitochondria was found in the left ventricle compared to controls and noninfarcted areas. In patients with AMI, an increase in mitochondria with deposits was found in the infarction area compared to controls and noninfarcted tissue within the same patient, suggesting that electron microscopical changes in mitochondria can be used for the diagnosis of AMI less than 3 h old.     

Multiplex amplification of mitochondrial DNA for human and species identification in forensic evaluation

We describe a method combining in a single-round polymerase chain reaction amplifications of both cytochrome b and hypervariable D-loop mitochondrial DNA allowing species determination and individual human identification. Following the amplification step, amplicons are first screened on an agarose gel. The presence of only one band indicates that the sample is nonhuman, while the presence of two bands indicates a human origin. Subsequent DNA sequencing of the hypervariable D-loop region DNA allows for individual human identification as the presence of cytochrome b fragment does not interfere with the analysis. Similarly, further species determination on the basis of the phylogenetically variable cytochrome b gene is possible by sequencing of the cytochrome b DNA fragment.     

Identification of DNA of human origin based on amplification of human-specific mitochondrial cytochrome b region

Species-specific differences in a non-polymorphic region of the mitochondrial cytochrome b gene appear to be large enough to allow human-specific amplification of forensic DNA samples. We therefore developed a PCR-based method using newly designed primers to amplify a 157-bp portion of the human mitochondrial cytochrome b gene. The forward and reverse primers were designed to hybridize to regions of the human mitochondrial cytochrome b gene with sequences differing from those of chimpanzee by 26% (7 bp/27 bp) and 26% (6 bp/23 bp), respectively. Using this primer pair, we successfully amplified DNA extracted from blood samples of 48 healthy adults. All these human samples produced a single band of the expected size on agarose gel electrophoresis, and the sequence of the single band was shown to be identical to that of the target region (157 bp) by sequence analysis. On the other hand, no visible bands were amplified from DNA extracted from blood samples of animals including non-human primates (chimpanzee, gorilla, Japanese monkey, crab-eating monkey) and other species (cow, pig, dog, goat, rat, chicken and tuna). Thus, DNA producing a single band following PCR amplification using this primer pair can be reasonably interpreted as being of human origin. In addition, aged biological specimens comprising bloodstains, hair shafts and bones were successfully identified as being of human origin, illustrating the applicability of the present method to forensic specimens.