实验性脑挫伤后caspase—1表达的研究

目的阐明不同程度及不同时间脑挫伤后caspase-1表达的变化。方法应用免疫组织化学染色、Western-blotting和RT-PCR方法对48例实验性脑挫伤大鼠的脑组织进行了检验,同时以3例非脑挫伤和3例假手术的脑组织做对照。结果脑挫伤后1h caspase-1即有表达,24-48h达高峰,挫伤后两周caspase-1阳性细胞仍维持较高水平。阳性细胞多集中于挫伤区及周围带皮质和脑实质内海马区,不同程度脑挫伤各组之间阳性细胞面积存在差异;损伤组caspase-1酶原裂解增加;损伤组caspase-1mRNA表达量明显高于对照组;不同程度脑挫伤组之间于各个时间段caspase-1mRNA表达未见差异。 结论 Caspase-1表达增加,可辅助诊断1h-14d的脑挫伤,并可根据caspase-1阳性细胞面积的变化来确定脑挫伤程度,同时对判断挫伤时间方面也有一定的价值。caspase-1参与脑挫伤后的神经细胞凋亡。     

大鼠脑挫伤后NF-κB表达的分子生物学研究

目的阐明不同程度及不同时间脑挫伤后NF-κB表达的变化。方法应用免疫组织化学染色、Westernblot和RT-PCR方法对48例不同程度实验性脑挫伤大鼠的脑组织进行了检验,同时以3例非脑挫伤和3例假手术大鼠的脑组织做对照。结果伤后1hNF-κB即有表达、24～48h达高峰,一周后停止表达。阳性细胞多集中于挫伤区及周围带皮质和脑实质内海马区;不同程度脑挫伤组之间于伤后各个时间段NF-κB表达无明显差异。结论本实验首次通过对不同程度脑损伤后NF-κB表达量的研究,找到其表达的时间性变化规律,对确定脑挫伤形成时间有意义,但不能作为判断脑挫伤程度的指标。     

大鼠不同程度脑挫伤后caspase-3表达的研究

目的阐明不同程度及不同时间脑挫伤后caspase-3表达的变化。方法应用免疫组织化学染色、Westernblot和RT-PCR方法对48例实验性脑挫伤大鼠的脑组织进行了检验,同时以3例非脑挫伤和3例假手术的脑组织做对照。结果伤后1hcaspase-3即有表达,24～48h达高峰,挫伤后14dcaspase-3仍维持较高水平。阳性细胞多集中于挫伤区及周围带皮质和脑实质内海马区,不同程度脑挫伤各组之间阳性细胞面积和灰度存在差异;损伤组caspase-3酶原裂解增加,不同程度脑挫伤各组之间存在一定的差异;损伤组cas鄄pase-3表达量明显高于对照组;不同程度脑挫伤组之间于各个时间段caspase-3mRNA表达未见差异。结论Caspase-3表达增加,可辅助诊断1h～14d的脑挫伤,caspase-3阳性细胞面积和灰度的变化及酶原裂解程度与脑挫伤程度有关。     

大鼠脑挫伤后caspase-3和HAX-1的表达

目的观察大鼠脑挫伤后半胱氨酸天冬氨酸蛋白酶3(caspase-3)和造血干细胞特异性相关结合蛋白-1(HCLS1-associated protein X-1,HAX-1)在损伤后不同时段的表达规律,探索损伤时间推断的新方法。方法建立成年SD雄性大鼠脑挫伤模型,随机分为脑挫伤后2 h、6 h、12 h、1 d、3 d、7 d组,假手术组和正常组。采用Western印迹法检测大鼠脑挫伤后caspase-3和HAX-1的蛋白表达。采用激光共聚焦显微镜检测技术对脑挫伤后HAX-1阳性细胞数和TUNEL染色细胞数进行观察。结果脑挫伤后,随着损伤时间的延长,caspase-3表达逐渐增强,3 d达到峰值,以后逐渐下降,7 d仍高水平表达(P<0.05)。HAX-1阳性细胞表达在伤后开始升高,6 h表达强度最高(P<0.05),12 h后逐渐下降,伤后3 d几乎测不到。TUNEL染色细胞数在伤后2 h明显增加,伤后3 d数量最多,此后逐渐减少,7 d仍维持较高水平(P<0.05)。结论大鼠脑挫伤后caspase-3、HAX-1的表达有时序性变化,可能成为脑损伤时间推断的新依据。     

大鼠创伤性脑损伤后Bcl-2及Fas-L的表达

目的 观察大鼠创伤性脑损伤后,脑组织中Bcl-2及Fas-L不同时间的表达变化,探讨其与脑损伤经过时间的关系。方法 自由落体法制作大鼠脑创伤模型,在伤后不同时间处死动物并取材后,进行Bcl-2、Fas-L免疫组织化学(SP法)和HE染色观察;图像处理大鼠脑挫伤后不同时间Bcl-2及Fas-L免疫反应阳性细胞并进行统计学分析。结果 染色阳性细胞主要分布在挫伤灶的周围。Bcl-2在伤后30min即有阳性表达,后逐渐加深;至伤后4h达高峰,然后随时间延长,阳性细胞染色强度逐渐减弱。脑挫伤后30min,损伤灶的周围即出现Fas-L阳性表达,随后呈缓慢增长;从伤后4h,Fas-L阳性反应的程度及数量逐渐显著增加。结论 脑挫伤后Bcl-2和Fas-L的表达在伤后不同时间,呈现一定的规律性变化。     

大鼠局灶性脑挫伤后Homer蛋白表达变化

目的 观察局灶性脑挫伤后Homer蛋白表达的变化规律,探讨其表达变化与损伤时间的相关性.方法 建立大鼠钝力性局灶性脑挫伤模型,应用免疫组织化学技术和Western印迹法观察脑损伤后不同时间脑组织中Homer蛋白表达的变化.结果 对照组、假手术组及伤后0.5h组脑组织中有少量Homer蛋白染色阳性细胞,伤后3h组脑组织H...     

大鼠脑挫伤后微管相关蛋白2 mRNA表达变化

目的观察大鼠脑挫伤后脑组织中微管相关蛋白2（microtubule associated protein 2,MAP-2）mRNA表达变化,探讨其时序性变化与脑损伤时间的相关性。方法参照Feeney法建立大鼠右顶叶脑挫伤模型,应用实时定量PCR技术检测挫伤区脑组织MAP-2 mRNA的表达情况。结果对照组大鼠脑组织内有低水平的MAP-2 mRNA表达;伤后1h,挫伤灶脑组织MAP-2 mRNA表达较正常对照组下降,伤后6 h降至最低;12 h～14 d逐渐增高,至14 d时仍维持在高表达水平。结论脑挫伤后MAP-2 mRNA的表达规律,在法医学实践中可以作为脑损伤时间推断的新方法之一。     

HSP70表达与脑挫伤经过时间的关系

目的观察大鼠脑挫伤后不同时间内HSP70蛋白表达的变化关系,探讨其与脑损伤时间的关系。方法应用免疫组织化学染色观察自由落体撞击大鼠脑挫伤后HSP70蛋白在伤后不同时间(0.5h、6h、12h、24h、3d、7d、14d、28d)表达情况。结果0.5h伤侧皮质挫伤灶周围HSP70阳性细胞表达开始增强,12h达高峰,24h降至较低,3d又再次升高,以后逐渐下降,28d恢复至正常对照组水平。结论HSP70免疫组化染色可以作为法医学推断早期脑损伤时间的敏感性指标之一;HSP70可作为判断脑损伤是否存在及区分生前和死后脑损伤的重要标志。     

大鼠钝力性脑挫伤后PSD-95的表达

目的检测脑挫伤修复过程中突触后致密蛋白(postsynaptic density protein 95,PSD-95)的表达,探讨其变化规律与损伤时间的相关性。方法雄性SD大鼠50只,随机分为8个实验组,1个对照组,每组5只。制作大鼠脑挫伤模型,于伤后3、6、12h和3、5、7、10d取脑组织,应用免疫组织化学技术和免疫蛋白印迹(Western blot)方法检测脑挫伤后不同时间脑组织中PSD-95的表达变化。结果对照组脑组织仅有少量PSD-95阳性细胞;实验组中,伤后3h、6h组脑组织出现较多PSD-95阳性细胞,12h组阳性细胞数量持续升高,伤后1d阳性细胞数下降,5d后又升高并达到高峰,7d、10d恢复;计算阳性率,统计分析结果显示,阳性细胞数与相邻上组比较,存在显著性差异。Western blot结果:挫伤后,3～12h表达量上升,1d下降,随后又逐步上升,5d达到高峰,7d、10d下降;应用Fluorchem V2.0 Stand Alone软件获取感光条带的平均灰度值,经统计分析,各组与相邻上组比较,存在显著性差异。结论大鼠脑损伤后损伤周边区PSD-95呈现升高→下降→再升高→再下降的表达规律,对损伤时间推断有一定的参考意义。     

大鼠脑挫伤后基质金属蛋白酶3的表达

目的 检测脑挫伤修复过程中基质金属蛋白酶3(matrix metalloproteinase-3,MMP-3)的表达,探讨其表达规律与损伤时间的相关性.方法 将大鼠分成对照组、假手术组和脑挫伤组.应用免疫组织化学技术和蛋白质印迹(Western blot)方法检测脑挫伤后不同时间脑组织中MMP-3的表达变化. 结果免疫组化结果:对照组及假手术组脑组织未见MMP-3阳性染色;伤后6h组脑组织出现MMP-3阳性染色,此后24h内染色逐渐增强,伤后5 d阳性细胞数及染色强度均达高峰,随之下降,伤后14d仍有少量MMP-3表达.Western blot结果:对照组及假手术组脑组织未见MMP-3阳性染色;挫伤后6h组出现MMP-3表达,随后表达量逐渐上升,5d达到高峰,以后逐渐下降,14d仍有表达.结论 大鼠脑挫伤修复过程中MMP-3的表达呈时序性变化规律,可望用于脑挫伤时间的推断.     

The study on expression of NF-kappaB in experimental brain contusion in rats

OBJECTIVE: To investigate the expression of NF-kappaB in different post-traumatic intervals and severity of brain injury. METHODS: Fifty-four brain tissue samples of slight (n=24), moderate (n=24) brain injury, sham (n=3) and control (n=3) of rat were examined by immunohistochemical staining, westernblot and RT-PCR. RESULTS: Up-regulating of NF-kappaB expression was found in tissues from traumatic brain injury compared with controls in early 1 hour after TBI, and reached peak at 24h and 48h and disappeared after 7 days. The expression of NF-kappaB mRNA has association with contusion severity. CONCLUSION: NF-kappaB may benefit to the estimation of posttraumatic intervals of brain injury.     

大鼠脑外伤后溶酶体酶Cathepsin—B和D的表达

目的研究大鼠脑外伤后溶酶体酶cathepsin-B和-D是否被激活及其不同时段表达变化,阐述其与凋亡执行因子caspase-3表达的关系,并探讨对脑外伤诊断及形成时间的意义。方法采用自由落体打击法建立脑外伤动物模型,并对模型及对照样本进行免疫荧光、双标和激光共聚焦检测,结果用SPSS10.0软件处理。结果脑外伤后1hcathepsin-B表达即增加,4～8d达高峰,脑外伤后32d仍处于高表达水平;cathepsin-D的表达于脑外伤后12h增加,4～8d达高峰,32d的表达仍然高于12h的表达水平。脑外伤初期,cathepsin-B和-D阳性细胞与caspase-3阳性细胞重叠较少,脑外伤后6h开始增加,32d仍然有很多阳性细胞重叠。结论脑外伤后cathepsin-B和-D被激活,其激活在脑外伤早期可能抑制细胞凋亡执行因子caspase-3的激活,之后(6h后)则与caspase-3起协同作用,共同促进细胞死亡;cathepsin-B和-D表达的时程变化对于脑外伤的法医学诊断和中晚期的时间推断有参考意义。     

创伤性脑损伤大鼠水通道蛋白4表达变化及法医学意义

目的观察大鼠颅脑损伤后不同时间内水通道蛋白4（AQP4）mRNA表达的变化，探讨AQP4在脑损伤经过时间推断中的意义。方法利用液压冲击法制作不同程度大鼠颅脑损伤模型，在伤后不同时间（0．5、2、6、12、24、48、72h），应用RT-PCR法检测脑组织AQP4 mRNA表达，同时以非损伤组做对照。结果不同程度颅脑损伤后0．5h脑组织AQP4 mRNA表达均开始上调（P〈0．01），6、12h依次增高，24h达到高峰，差异均有统计学意义（P〈0．01），72h时仍维持较高水平（P〈0．01）；0．5h时轻度、中度、重度脑损伤时AQP4 mRNA的表达差异两两之间无统计学意义（P〉0．05），2、6、12、24、48、72h轻度、中度、重度脑损伤时AQP4 mRNA的表达差异两两之间有统计学意义（P〈0．01）。结论颅脑损伤后AQP4 mRNA呈现出时序性变化，其变化规律可望成为法医学推断早期脑损伤时间的指标之一。     

Quantitative immunohistochemical analysis of human brain basic fibroblast growth factor, glial fibrillary acidic protein and single-stranded DNA expressions following traumatic brain injury

Previous studies demonstrated the healing process after traumatic brain injury (TBI), usually at the site or in the area adjacent to the injury, in connection with wound timing. However, the whole brain condition after TBI has not been elucidated clearly. In the present study, we investigated immunohistochemistry of the basic fibroblast growth factor (bFGF), glial fibrillary acidic protein (GFAP) and single-stranded DNA (ssDNA) in the parietal lobe and hippocampus distant from the primary injury site in forensic autopsy cases of TBI (n=174). Characteristic findings were detected with regard to brain compression signs and survival time (ST). Peracute deaths (n=22) had a lower GFAP positivity in the parietal white matter. Fatalities without a brain compression sign (parahippocampal herniation/Duret hemorrhage; n=53) had a lower brain weight without glial loss; however, GFAP positivity in the parietal white matter was decreased during ST of <12h, and glial bFGF positivity was increased at each site in deaths after 12h to 3 days, followed by a delayed neuronal loss after 3 days. Fatalities with a brain compression sign (n=78) showed a higher brain weight, and gradual glial and neuronal losses with an early increase of glial bFGF positivity in the parietal cerebral cortex (ST <0.5h). This was followed by an increase of glial bFGF positivity in other sites (ST, 6-24h), and final decreases of glial bFGF and GFAP positivities with increased neuronal ssDNA positivity in the parietal lobe and hippocampus (ST >3 days), which were detected in earlier deaths despite decompressive craniectomy (ST, 12-60h; n=21). These observations suggest that the combined use of bFGF, GFAP and ssDNA immunohistochemistry can be used to evaluate the severity of damage and response of brain after TBI.     

大鼠实验性脑挫伤后不同时间脑apoE的表达

目的观察大鼠实验性脑挫伤后脑内apoE蛋白变化的时空性规律。方法采用自由落体撞击法致大鼠脑挫伤模型,观察伤后不同时间(0.5h、2h、6h、12h、24h、3d、7d、14d)apoE蛋白的变化,并用计算机图像分析技术作定量统计分析。结果伤后0.5h组脑皮质神经元apoE出现阳性表达,3d达到高峰,随后下降;伤后0.5h组在海马出现apoE强阳性反应,CA1区在伤后3d达到高峰,而CA2~CA4区在24h达到高峰,随后逐渐下降,伤后海马apoE表达以CA1区最强。结论挫伤后apoE时空性变化规律可作为脑损伤时间推断、早期诊断及生前伤和死后伤鉴别的一个新的参考指标。     

小鼠脑外伤后Apelin-13对自噬相关蛋白表达的影响

目的观察Apelin-13对小鼠脑外伤（Traumaticbraininjury,TBI）自噬相关蛋白的影响,并初步探讨其对小鼠脑外伤后自噬相关蛋白调节的作用机制。方法取健康雄性CD-1小鼠,随机分为假手术（sham）组、生理盐水（sa-line）组、Apelin-13组。Apelin-13组和saline组在建立脑外伤模型前10min,分别注射Apelin-13（0．3μg／g）或等量生理盐水于侧脑室,然后利用Western-Blot检测脑外伤后24h、48h组大脑皮质自噬相关蛋白LC3、P62、Beclin-1和Bcl-2等的表达情况。结果与sham组相比,在脑外伤后24h、48h,saline组自噬相关蛋白LC3-Ⅱ／LC3-Ⅰ比值,Beclin-1的蛋白表达均被显著上调（P〈0．01）;同时Bcl-2、P62的蛋白表达水平被显著下调。然而,与saline组相比,Apelin-13组可显著下调自噬相关蛋白LC3-Ⅱ／LC3-Ⅰ比值和Beclin-1的蛋白表达水平（P〈0．01）;同时显著上调Bcl-2和P62的表达水平;亦明显降低Beclin-1／Bcl-2的比值。结论Apelin-13可以明显抑制脑外伤后小鼠大脑皮质细胞的自噬活性,这一作用可能是通过调节Beclin-1、Bcl-2蛋白表达水平来实现的。     

Could NF-kappaB and caspase-3 be markers for estimation of post-interval of human traumatic brain injury?

BACKGROUND: Previous studies in a rat model showed expressions of caspase-3 (p20) and NF-kappaB (p65) in different time after TBI. We test the activation changes of caspase-3 and NF-kappaB of human specimen after traumatic brain injury (TBI) in this study to see whether they could be markers to estimate post-intervals of TBI for forensic practice. MATERIAL AND METHODS: Caspase-3 (p20) and NF-kappaB (p65) immunohistochemical staining were performed on 39 TBI specimens (dead from TBI) and eight controls (dead from none TBI reasons) grouped 0, 12, 24, 48, 72, 168, 264 and 480 h. Positive cells were counted and image analysis techniques were used to determine the morphological changes in each group. RESULTS: Immunohistochemical analysis showed a marked induction of caspase-3 (p20) in every injured group compared with normal controls; each positive group has it's morphological character with variant positive cell count. NF-kappaB (p65) did not showed markedly change compared with normal controls until 168 h after TBI and almost all nerve cells were stained by NF-kappaB (p65) in 264 and 480 h groups. CONCLUSION: NF-kappaB (p65) could contribute to estimate delayed death cases after TBI for forensic applications. Caspase-3 (p20) estimating post-TBI intervals are dubious but could suggest TBI exists.     

The expression of excitatory amino acid transporter 2 in traumatic brain injury

It is well recognized that glutamate is the major excitatory neurotransmitter, which is removed from the synaptic cleft by excitatory amino acid transporter 2 (EAAT2) located on the perisynaptic astrocytes and that neuronal death has been associated with an increased extracellular glutamate concentration. In this study, we have immunohistochemically demonstrated the expression of EAAT2 protein in the human brain after traumatic brain injury (TBI). The EAAT2 expression patterns can be divided into three types: continuous and highly extensive staining (E); continuous but sporadic staining (M); and sporadic pattern staining (S). In six of the nine short survival cases studied (1 h to 1 day), continuous and highly extensive staining for EAAT2 (E type) was observed in the ipsilateral cerebral cortex. On the other hand, we were able to demonstrate weak staining (S and M types) in 5 of the 7 long survival cases (> or =1 day) and in 12 of the 14 very short survival cases (<1 h) studied. Similar findings were obtained in the contralateral cerebral cortex and also in the ipsilateral hippocampus. In addition, positive staining for glial fibrillary acidic protein was detected around the cerebral contusion, but the EAAT2-positive expression was not observed in the same region for all of the six short and long survival cases (> or =1 h) after TBI. These findings clearly showed the differences in EAAT2 expression in the cerebral cortex according to the survival time and severity of cerebral contusion after TBI. Therefore, we emphasized that EAAT2 might play an important role in contributing to extracellular glutamate concentrations and secondary brain injury after TBI.