神经节苷脂对脑缺氧缺血后新生大鼠海马CA1区 N-甲基-D-天门冬氨酸受体表达的影响

目的 研究新生大鼠缺氧缺血性脑损伤(HIBD)后海马区N-甲基-D-天门冬氨酸受体(NMDAR)及NMDARmRNA表达的变化和神经节苷脂(GM1)对其的影响。方法 建立HIBD模型。用免疫组化及原位杂交方法检测缺氧缺血(HI)和GM1干预后不同时间点NMDA受体I型亚单位(NR1)阳性细胞及NR1mRNA阳性细胞的表达。结果 HI后新生大鼠海马CA1区NR1及NR1mRNA表达增强,GM1可使其受体表达下调(P<0.05)。结论 GM1可使新生大鼠海马CA1区NR1及NR1mRNA表达下调,对新生大鼠缺氧缺血性脑损伤具有保护作用。     

Release of pig leukocytes during pig kidney perfusion and characterization of pig lymphocyte carbohydrate xenoantigens

The Galalpha1-3Gal (alphaGal) antigen is considered the main xenoantigen in the pig to human species combination but other porcine antigens have to be considered such as the swine lymphocyte antigen (SLA), the blood group A/O and the Hanganutziu-Deicher (H-D) antigens. The H-D antigens are N-glycolyl-neuraminic acid (NeuGc) terminated gangliosides that are widely distributed in mammalian species but absent in humans. Upon exposure to a vascularized pig organ, the human recipient can be immunized by direct interaction with the pig tissue or/and by transfer of tissue/cells from the organ into the recipient. In the present work, we describe the release of cells from porcine kidneys upon perfusion and the expression of glycolipid based alphaGal, blood group A/O and H-D antigens in pig lymphocytes. Pig kidneys were flushed with 20 ml of NaCl or Lidocain containing 5000 U heparin, and thereafter perfused with 3000-ml perfusion solution and the cells released were counted and examined microscopically. Neutral glycolipid and ganglioside fractions were extracted from purified pig lymphocytes. The extracted components were characterized by thin layer chromatography, degradation and mass spectrometry. The expression of alphaGal and H-D epitopes on cells released from pig kidneys and purified pig lymphocytes were studied by immune electron microscopy. A total amount of about 300 x 106 leukocytes, mainly lymphocytes were released in the perfusate from the kidneys, of which about 100 x 106 cells were eluated in the 600 to 2400 ml perfusate fraction. Immunelectron microscopical analysis with Griffonia simplicifolia isolectin B4 showed staining of pig leukocytes and other cells, morphologically similar to endothelial cells, released in the perfusate. The purified porcine lymphocytes contained 930 microg neutral glycolipid (4.2 microg/mg cell protein) of which 95% was glycolipids with one to four sugar residues. Immunostaining of the neutral glycolipid fractions revealed alphaGal terminated compounds migrating in the five and 10 to 12 sugar regions and blood group A compounds in the six and eight sugar regions. Two major gangliosides NeuGc-GM3 and NeuGc-GD3 were found in the pig lymphocytes. In a patient extracorporeally xenoperfused with a pig kidney, an increased staining of both alphaGal terminated structures as well as the H-D reactive gangliosides were found in the post-perfusion serum samples. In summary, leukocytes, mainly lymphocytes are released from pig kidneys during perfusion which may contribute to immunization of human xenograft recipients.     

神经节苷脂对大鼠脊髓损伤后微管相关蛋白-2表达的影响及意义

[目的]通过观察单唾液酸四己糖神经节苷脂(monosialotetrahexosyl gangliosides,GM-1)对于大鼠脊髓损伤(spinal cord injury,SCI)后微管相关蛋白-2(microtubule-associated protein 2,MAP-2)表达及运动功能恢复是否能够产生影响来探讨CM-1对大鼠脊髓损伤后神经细胞的保护作用及其机制.[方法]Wistar雌性大鼠66只(体重260～300 g),随机取6只作为正常对照组,余60只采用改良Allen's打击法于T9-11节段椎管制作大鼠急性SCI模型,并随机分为GM-1组(A组)和生理盐水对照组(B组)两组,每组各30只.分别于术后1、7、14、28、56 d采用Rivilin斜扳试验、改良Tarlov评分评价大鼠后肢运动功能恢复程度后处死取材,每组各时相点6只.以组织学和免疫荧光染色观察大鼠脊髓损伤的修复情况.[结果]术后7d起,Rivilin斜扳试验和Tarlov评分在A、B组间比较有显著性差异(P<0.0105),即A组功能恢复明显优于B组.术后56 d:HE染色示A组大鼠脊髓损伤处无明显空洞和瘢痕组织,有各种形态细胞形成,部分细胞有明显分化特征;B组脊髓断端被瘢痕组织填塞,可见大量炎性细胞和成纤维细胞浸润,并有较大脊髓空洞形成.免疫荧光染色发现,A组各时相点MAP-2表达呈阳性细胞数较B组高,差异有统计学意义(P <0.0105).[结论]SCI后,动物神经功能的恢复与MAP-2的表达呈一定的相关性;GM-1可通过增强脊髓损伤后MAP-2的表达来保护大鼠受损后脊髓的神经元.     

Uniform distribution and similar turnover rates of individual gangliosides along axons of retinal ganglion cells in the chicken

In 5-month-old chickens, an intracranial injection of N-[³H]acetylmannosamine led to a labelling of all optic lobe ganglioside species in a fashion parallelling the relative ganglioside distribution. In contrast, after an intraocular injection of the same precursor, the optic nerve and the optic lobe connected to the injected eye, possessed an exceptionally high labelling of GD1a (in comparison with GD1a-sialic acid), and only negligible incorporation of radioactivity into the myelin-specific GM4 and into a fraction migrating close to GM1. Subtracting both these very low labelling fractions from the total gave a percentage distribution of ganglioside sialic acid which now corresponded well to the distribution of radioactivity along the whole optic nerve, including the region of nerve terminals in the optic lobe. This pattern of ganglioside labelling, which indicates that GD1a carries about 60% of total ganglioside sialic acid of retinal ganglion cell axons, did not change remarkably during post-hatching development up to 5 months. Long-time incorporation studies revealed similar turnover rates of the main retinal ganglion cell gangliosides. The average half-lives were 34 (GD1a), 35 (GQ1b), 36.3 (GT1b) and 38.5 days (GD3). The findings suggest that the retinal ganglion cell axons and their presynaptic terminals possess a similar ganglioside pattern, characterized by a high content of GD1a.     

鼠神经生长因子联合神经节苷脂治疗新生儿缺氧缺血性脑病的Meta-分析

目的 系统评价鼠神经生长因子联合神经节苷脂治疗新生儿缺氧缺血性脑病（HIE）的疗效和安全性。方法 计算机检索中国期刊全文数据库（CNKI）、维普中文科技期刊全文数据库（VIP）、中国生物医学文献数据库（CBM）、万方数据库、PubMed、EMbase等数据库,收集鼠神经生长因子联合神经节苷脂治疗新生儿HIE的随机对照研究,提取资料并评价质量后,采用RevMan 5.1软件进行Meta-分析。结果 共纳入8篇文献,716例患儿;Meta-分析结果显示,与单用神经节苷脂比较,鼠神经生长因子联合神经节苷脂：显著提高临床有效率[RR=1.32,95%CI（1.22,1.43）,P<0.01]和NBNA评分[MD=4.00,95%CI（3.54,4.46）,P<0.01];显著缩短意识恢复时间[MD=-1.74,95%CI（-2.44,-1.04）,P<0.01]、惊厥消失时间[MD=-1.47,95%CI（-1.88,-1.06）,P<0.01]、肌张力恢复时间[MD=-2.73,95%CI（-3.19,-2.28）,P<0.01]和反射恢复时间[MD=-2.57,95%CI（-3.32,-1.82）,P<0.01];显著降低血清神经元特异性烯醇化酶（NSE）[MD=-5.04,95%CI（-6.26,-3.82）,P<0.01]和血管内皮生长因子（VEGF）[MD=-29.63,95%CI（-33.11,-26.16）,P<0.01];显著提高智力发育指数（MDI）[MD=8.87,95%CI（7.92,9.82）,P<0.01]和心理运动发育指数（PDI）[MD=9.89,95%CI（8.52,11.27）,P<0.01]。结论 鼠神经生长因子联合神经节苷脂对新生儿HIE受损脑神经元及神经胶质细胞神经元功能具有协同修复作用,与协同降低血清NSE和VEGF水平有关。     

Air Pollutant Sulfur Dioxide-induced Alterations on the Levels of Lipids,Lipid Peroxidation and Lipase Activity in Various Regions of the Rat Brain

Abstract: The exposure of rats to SO₂ (10 p.p.m.) for one hour daily for 30 days caused depletion of total lipids in all brain areas. The contents of phospholipid were elevated in cerebellum and brain stem, but were depleted in cerebral hemisphere. Cholesterol levels showed an increase in various brain regions. On the other hand, gangliosides were increased in cerebellum and brain stem, but were decreased in cerebral hemisphere. Interestingly, cholesterol/phospholipid ratio was increased in different regions of the brain. Lipase activity was elevated in cerebral hemisphere. Lipid peroxidation showed marked increment in whole brain and in all the brain areas studied. The results suggest that SO₂-exposure induces degradation of lipids. Interestingly, the lipid contents are affected differentially in the various parts of the brain.     

Ganglioside composition and histology of a spontaneous metastatic brain tumour in the VM mouse.

Glycosphingolipid abnormalities have long been implicated in tumour malignancy and metastasis. Gangliosides are a family of sialic acid-containing glycosphingolipids that modulate cell-cell and cell-matrix interactions. Histology and ganglioside composition were examined in a natural brain tumour of the VM mouse strain. The tumour is distinguished from other metastatic tumour models because it arose spontaneously and metastasizes to several organs including brain and spinal cord after subcutaneous inoculation of tumour tissue in the flank. By electron microscopy, the tumour consisted of cells (15 to 20 microm in diameter) that had slightly indented nuclei and scant cytoplasm. The presence of smooth membranes with an absence of junctional complexes was a characteristic ultrastructural feature. No positive immunostaining was found for glial or neuronal markers. The total ganglioside sialic acid content of the subcutaneously grown tumour was low (12.6 +/- 0.9 microg per 100 mg dry wt, n = 6 separate tumours) and about 70% of this was in the form of N-glycolylneuraminic acid. In contrast, the ganglioside content of the cultured VM tumour cells was high (248.4 +/- 4.4 microg, n = 3) and consisted almost exclusively of N-acetylneuraminic acid. The ganglioside pattern of the tumour grown subcutaneously was complex, while GM3, GM2, GM1, and GD1a were the major gangliosides in the cultured tumour cells. This tumour will be a useful natural model for evaluating the role of gangliosides and other glycolipids in tumour cell invasion and metastasis.     

不同膜脂对米氏凯伦藻溶血毒素致溶血作用的影响

目的研究不同膜脂对米氏凯伦藻溶血作用的影响。方法于反应体系中加入外源性卵磷脂、鞘磷脂、L-α-磷脂酸、胆固醇和神经节苷脂等5种膜脂,观察其对米氏凯伦藻溶血毒素活性的影响;分析溶血毒素对不同动物红细胞的溶血活性,比色法测定不同动物红细胞膜中神经节苷脂的总量。结果 5种膜脂中,只有神经节苷脂对溶血活性具有显著的抑制作用(P<0.05)。加入神经节苷脂10min后,其溶血活性仅为16.05%,而对照组为35.65%。兔红细胞对毒素最为敏感,溶血百分数明显高于相应大鼠(P<0.05)和美国红鱼(P<0.01);兔、大鼠和美国红鱼每克冻干红细胞膜上脂结合唾液酸(LBSA)的量分别为672.08、585.97和431.52μg/g,兔红细胞膜上LBSA量显著高于大鼠和美国红鱼(P<0.05)。结论外源神经节苷脂可显著抑制米氏凯伦藻溶血毒素的活性,不同动物红细胞对毒素的敏感性与其红细胞膜上神经节苷脂的量呈明显相关。     

新生鼠缺氧缺血性脑损伤凋亡基因的变化及神经节苷酯的治疗作用

【目的】探讨新生大鼠缺氧缺血性脑损伤(hypoxic-ischemia brain damage，HIBD)后Bcl-2、Bax基因表达与细胞凋亡的关系及神经节苷酯(gangliosides，GM1)对其的影响。【方法】建立新生鼠HIBD动物模型，用TUNEL法和免疫组化法观察缺氧缺血和GMI干预后不同时间点细胞凋亡情况及凋亡基因Bcl-2、Bax的变化。【结果】缺氧缺血组随时间延长脑组织中Bcl-2、Bax的表达增加，Bcl-2／Bax的比值下降，同时凋亡细胞数增加，表明Bcl-2、Bax两者比值的降低促进凋亡的发生。GM1干预组Bcl-2表达增加显著，降低了Bax的表达，凋亡细胞减少。【结论】GM1可能通过改变凋亡基因的表达而抑制神经细胞的凋亡过程。     

肝细胞癌变时神经节苷脂对转铁蛋白受体介导的内吞作用的影响

目的：研究肝细胞癌变时神经节苷脂ＧＭ３和ＧＤ３的变化对转铁蛋白受体介导的内吞作用的影响及其在促进肝癌生长中所起的作用。方法：采用放射性核素标记配体受体结合法，及洗脱法测定转铁蛋白与其受体的结合以及转铁蛋白受体介导的内吞作用；用ＭＴＴ比色法测定细胞生长情况。结果：（１）ＧＭ３抑制肝癌细胞的生长，ＧＤ３则促进肝癌细胞的生长；（２）这种影响与转铁蛋白对细胞的作用直接相关；（３）此相关作用不是通过影响转铁蛋白与其受体的结合，而是通过影响转铁蛋白受体介导的内吞作用而实现的。结论：肝细胞癌变时神经节苷脂组成的变化能明显加快转铁蛋白受体介导的内吞作用，增加肝癌细胞对转铁蛋白的摄取，从而促进肝癌细胞的生长与增殖。