脂多糖对大鼠多巴胺能神经元毒性作用的研究

目的　建立新的帕金森病 (Parkinson’sdisease ,PD)动物模型 ,探讨其发病机制。方法　在大鼠脑黑质(substantianigra ,SN)内注射脂多糖 (Lipopolysaccharide ,LPS)后 ,按大鼠不同存活期用高效液相色谱 (HPLC)来测定脑内多巴胺 (Dopamine,DA)及其代谢产物的含量 ;用免疫组化法观察酪氨酸羟化酶 (Tyrosinehydroxylase ,TH)阳性神经细胞、小胶质细胞的形态及数量变化。结果　DA及其代谢产物的含量在LPS注射侧随时间不同有不同程度下降 ,于第 14天达到最低 (P <0 0 1) ;注射侧黑质TH阳性神经元可以达到全部消失 ,该处可见大量被激活并有形态改变的小胶质细胞。结论　LPS可导致大鼠黑质多巴胺能神经元的损害     

Lactacystin诱导帕金森病大鼠黑质胶质细胞的变化

目的观察蛋白酶体抑制剂Lactacystin诱导大鼠黑质胶质细胞的变化、炎性介质NF-κB的表达。方法采用立体定向术将蛋白酶体抑制剂Lactacystin 10μg注射至大鼠黑质部位,免疫组织化学法观察黑质区多巴胺(DA)能神经元、小胶质细胞、星形胶质细胞的变化,炎性介质核转录因子κB(NF-κB)的表达。结果注射Lactacystin 3周,阿朴吗啡腹腔注射后出现典型旋转行为;8周后实验组大鼠损毁侧黑质酪氨酸羟化酶(TH)阳性细胞数明显减少,黑质小胶质细胞及星形胶质细胞的数量均增加,NF-κB表达增强。结论蛋白酶体抑制剂Lactacystin能激活大鼠黑质小胶质细胞及星形胶质细胞,诱导炎性介质表达。     

脂多糖LPS诱导的神经炎症对小鼠认知功能的影响及相关机制分析

为研究脂多糖(lipopolysaccharide,LPS)对小鼠认知功能的影响,本研究将18只C57BL/6小鼠随机分为两组,即正常对照组和LPS处理组,每组各9只小鼠。在腹腔注射LPS 24 h后行水迷宫实验检测小鼠行为学变化。此外,本研究采用Western blotting和免疫组化检测小鼠脑内小胶质细胞特异性标记物离子通道相关钙衔接蛋白(ionized calcium binding adapter,IBA1)的表达,TUNEL凋亡法检测小鼠脑内神经元凋亡情况。实验结果发现LPS处理后小鼠认知功能下降。Western blotting和免疫组化结果均提示LPS处理后小鼠脑中IBA1表达量增加,小胶质细胞激活;TUNEL提示LPS处理后小鼠脑内出现大量凋亡神经元,由此推断LPS可能通过激活小胶质细胞,扩大神经炎症反应,增加神经元凋亡导致小鼠认知功能下降。     

灵芝提取物通过抑制小胶质细胞激活保护多巴胺能神经元

近来的研究表明,神经炎症在帕金森病(Parkinson’sdisease,PD)的发病过程中起着重要的作用,因此通过抑制神经炎症而保护黑质多巴胺能神经元可能是一种具有潜力的治疗策略。本研究组前期的临床试验表明,灵芝(Ganoderma lucidum,GL)具有潜在的神经保护作用,可能通过抗炎及免疫调节机制发挥其保护作用。本研究在神经元-小胶质细胞共培养的模型中观察了GL的神经保护作用,并探讨其可能的保护机制。小胶质细胞单独或与MES23.5多巴胺能神经细胞共培养,脂多糖(lipopolysaccharide,LPS,0.25μg/mL)孵育24h作为阳性对照,试验组分别加入GL提取物(50~400μg/mL)和/或MPP+处理的MES23.5细胞膜碎片(150μg/mL);检测小胶质细胞激活情况及其产生的有害因子和MES23.5细胞[3H]DA摄取能力。结果显示,LPS或MPP+损伤的MES23.5膜碎片均可激活小胶质细胞。同时,GL提取物可以显著降低小胶质细胞源性炎症因子和细胞毒性因子(NO、TNF-α、L-1β)的产生,并呈一定的浓度依赖性;并同样可以下调TNF-α和L-1β mRNA水平的表达。此外,GL还可明显对抗由小胶质细胞激活和MPP+介导的多巴胺能神经细胞[3H]DA摄取抑制。以上结果提示,GL主要通过抑制小胶质细胞激活,减少其神经毒性因子的释放而保护多巴胺能神经细胞。GL可能成为治疗PD的潜在药物。     

雌激素对6-羟基多巴胺损伤黑质多巴胺能神经元的保护作用

本研究以P50听觉诱发电位(P50 auditory evoked potential, P50)和酪氨酸羟化酶(tyrosine hydroxylase, TH)阳性细胞计数作为黑质功能和形态学指标,动态追踪研究雌激素对6-羟基多巴胺(6-hydroxydopamine, 6-OHDA)损伤黑质多巴胺(dopamine, DA)能神经元的作用.将大鼠分为4组:(1)正常雌性大鼠对照组;(2)单纯帕金森氏病(Parkinson's disease, PD)模型组;(3)双侧去卵巢PD模型组;(4)去卵巢回补3d雌激素的PD模型组.在大鼠清醒和安静的生理状态下连续14d记录黑质的P50,并检测黑质TH 细胞数目的变化.结果显示:单纯PD模型大鼠黑质P50的T/C值较正常雌鼠降低40.60%(P<0.01),其损伤侧黑质TH 细胞数目减少64.74%(P<0.01);去卵巢PD模型大鼠黑质P50的T/C值较单纯PD模型大鼠进一步降低45.88%(P<0.01),同时其黑质TH 细胞数目值也进一步减少57.26%(P<0.01),表明急性缺乏生理水平性腺雌激素将增大6-OHDA损伤黑质DA能神经元的程度,同时使黑质的感觉门控(sensory gating, SG)功能明显受损;去卵巢后回补3d生理剂量雌激素,可明显改善大鼠黑质的SG功能,提高TH 细胞数量(与去卵巢PD模型大鼠比较,P<0.01),其黑质损伤程度与单纯PD模型大鼠相当.以上结果提示,生理水平的雌激素具有提高黑质DA能神经元对伤害性刺激耐受性的神经保护作用.缺乏性腺源性的雌激素时,及时给予生理剂量的雌激素可以减轻神经毒素6-OHDA对黑质DA能神经元结构和功能的损伤.     

百草枯和代森锰所致帕金森病小鼠黑质GFAP的表达变化

目的:研究联合应用百草枯(Paraquat,PQ)和代森锰(Maneb,MB)对帕金森病(Parkinson′s disease,PD)小鼠脑黑质神经胶质原纤维酸性蛋白质(Glial fibrillary acldic protein,GFAP)的表达变化。方法:PQ/MB建立C57BL/6J小鼠PD模型,利用免疫组化方法观察不同时间点小鼠黑质区酪氨酸羟化酶(Tyrosine hydroxylase,TH)和GFAP表达变化及相互关系。结果:模型组黑质致密部(Substantial nigra pars compacta,SNpc)区残留的TH阳性神经元呈进行性下降趋势,显著低于对照组的相应时间点(P＜0．01),黑质区星形胶质细胞反应性增多并呈现明显活化状态。结论:PO/MB能诱导小鼠产生渐进性且不可逆的PD样改变,星形胶质细胞可能参与多巴胺能神经元的病理损伤过程。     

星形胶质细胞在MPTP帕金森小鼠脑内的变化研究

目的：研究神经毒素1-甲基-4-苯基-1,2,3,6-四氢吡啶（1-methy-4-phenyl-1,2,3,6-tetrahy-dropyridine,MPTP）对小鼠脑内星形胶质细胞及肿瘤坏死因子-α（Tunlomecrosis factor alpha,TNF-α）的影响,了解MPTP致帕金森病发病机制。方法：将神经毒素MPTP注入C57BL／6小鼠腹腔内,制备帕金森病动物模型。观察注药后小鼠行为学变化,免疫组化检测各时间点多巴胺能神经元缺失和星形胶质细胞增生与激活情况,以及TNF-α表达水平的变化。结果：MPTP组黑质多巴胺（dopamine,DA）能神经元的数量随注射天数增加而持续减少,星形胶质细胞数量明显增高,GFAP及TNF-α在模型组黑质内有中强阳性表达,与对照组相比差异有统计学意义（P〈0．05）。结论：MPTP可诱导星形胶质细胞的激活和增生,启动脑内炎症反应而介导DA神经元死亡。     

猫视网膜多巴胺能神经元的形态和发育

本文报道用酪氨酸羟化酶(TH)免疫细胞化学方法研究猫生后发育期多巴胺(DA)能神经元的形态和发育。TH阳性反应的DA能神经元在生后第一天(P_1)的视网膜中已经出现。按形态学特征——胞体大小、形状、突起分层,以及免疫反应强度可分为THⅠ型和THⅡ型两类。THⅠ型是大的强阳性反应的DA能细胞,包括通常DA能无长突细胞、移位DA能无长突细胞和DA能类网间细胞。它们随发育年龄增长逐渐成熟。THⅡ型是小的弱阳性反应的DA能细胞,不随年龄而生长发育,相反在开眼(P_(7-10))后细胞数量明显下降,至P_(30)时完全消失。开眼后,THⅠ细胞除胞体增大外树突发育特别迅速。它们的胞体直径从11.8μm(P_1时)增大至14.2μm(P_(30)时),相应的树突野和分枝交叉也明显增加。P_1时,树突分枝少而直,末端有许多生长锥。在中央网膜的树突有棘状附属物。至P_(13)时生长锥减少,许多分枝交叉形成简单的网状,同时树突“棘”完全消失,可能发展为环的一部份。至P_(30)时,树突分枝在内网从层的外层形成复杂的网络,其间有无数与杆型AⅡ无长突细胞构成突触联系的环形结构,相似于成年者。在生后发育过程中,开眼后适宜光照对THⅠ细胞成熟的影响以及神经递质变化的可能性,我们在文中进行了讨论。     

6-OHDA制备的帕金森病大鼠黑质神经元的超微结构改变

目的观察6-羟多巴胺(6-OHDA)单侧注射制备的帕金森病(PD)大鼠多巴胺(DA)能神经元的超微结构改变。方法单侧微量注射6-OHDA制备PD大鼠模型,用免疫荧光组织化学方法观察正常侧与6-OHDA注射侧黑质酪氨酸羟化酶(TH)阳性神经细胞及神经纤维的变化;并利用免疫电镜技术观察大鼠正常侧与注射侧黑质致密部DA能神经元的超微结构。结果免疫荧光法显示注射侧黑质致密部TH阳性细胞数和网状部TH阳性纤维面积与正常侧的百分比平均值分别为21.83%,23.19%。免疫电镜显示:TH免疫反应阳性产物表达于PD大鼠正常侧DA能神经元的高尔基复合体质膜面及胞质内,电子密度较高,注射侧很少见或几乎未见,且注射侧线粒体嵴有不同程度的溶解,呈空泡样变或髓样变,粗面内质网脱颗粒。结论6-OHDA可引起DA能神经元发生凋亡的超微结构改变。     

帕金森病大鼠模型中脑腹侧被盖区多巴胺能神经元改变及c-Jun蛋白表达

目的探讨帕金森病(Parkinson disease,PD)大鼠模型中脑腹侧被盖区(ventral tegmental area,VTA)多巴胺能神经元的改变及其c-Jun蛋白表达情况,探讨其可能机制。方法应用6-羟基多巴胺(6-hydroxydopamine,6-OHDA)单侧一点注射大鼠黑质致密区(substantia nigra compacta,SNc),特异性毁损DA能神经元;术后1d、7d、14d、21d腹腔注射阿朴吗啡(apomorphine,APO)诱发行为学观察、电镜、尼氏染色观察中脑VTA神经元的改变,免疫组织化学ABC观察其DA能神经元酪氨酸羟化酶(tyrosine hydroxylase,TH)及c-Jun的改变并进行图像分析,Western blot观察c-Jun蛋白表达。结果APO诱发PD大鼠模型异常旋转行为,尼氏染色及电镜见PD大鼠中脑VTA有神经细胞肿胀、坏死等变化,VTA TH阳性(TH )神经元数量减少,形态学改变。APO诱导的旋转实验≥7转/min,VTA毁损侧c-Jun表达。结论中脑VTA DA能神经参与PD模型大鼠的改变;APO能诱导6-OHDA PD模型大鼠的旋转行为,其强弱可能与TH 神经元数量直接相关;c-Jun表达与DA能神经元毁损程度有一定的关系。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.