人胎儿雪旺氏细胞的体外培养及其纯化研究

本实验用酶消化法从孕１４～１９周人胎儿周围神经中分离培养雪旺氏细胞，结合差速贴壁和阿糖胞苷处理进行纯化，根据Ｓ－１００蛋白免疫细胞化学染色和形态学特征，分析不同时期雪旺氏细胞的纯化程度。实验结果显示：培养４ｄ，倒置相差显微镜下观察，雪旺氏细胞呈典型的双极或三极形，端对端或旋涡状排列，Ｓ－１００蛋白免疫细胞化学染色呈阳性反应，其比例约占９８％；在２～３周内，雪旺氏细胞的纯度维持在８５％～９０％；培养３５ｄ，雪旺氏细胞约占８０％；单纯采用阿糖胞苷或差速贴壁处理，培养３５ｄ，雪旺氏细胞约占７０％；原代培养９２ｄ，传代１１代细胞生长良好。实验结果表明，多种方法联合使用较单一方法所得的纯度高。本方法快速、简便，能为雪旺氏细胞作为移植材料提供足够的来源。     

乳鼠雪旺氏细胞的纯化培养研究

目的：获得高纯度的乳鼠雪旺氏细胞。方法：采用出生后３～５天乳鼠的坐骨、臂丛神经，植块法培养乳鼠雪旺氏细胞；并通过精细剥除神经外膜、组织块反复再植、低浓度胰酶快速消化、差速贴壁法的有机结合对雪旺氏细胞进行纯化；继用抗Ｓ－１００蛋白单抗通过间接免疫荧光法及ＡＢＣ法进行细胞鉴定。结果：首次植块获得的细胞经纯化后雪旺氏细胞可高达８５％以上，反复植块者可达９５％，甚至高达９８％。结论：本方法简单、稳定，所获得的雪旺氏细胞纯度高、数量大、受非实验因素影响小     

雪旺氏细胞源神经营养蛋白的125碘标记物制备与鉴定

雪旺氏细胞源神经营养蛋白（Ｓｃｈｗａｎｎ－ｃｅｌｄｅｒｉｖｅｄｎｅｕｔｒｏｐｈｉｃｐｒｏｔｅｉｎ,ＳＣＤＮＴＰ）是从雪旺氏细胞中提取的一种神经营养蛋白,分子量为５４×１０３,尤其对运动神经元有较强的营养支持和促进其损伤后修复作用［１］。但ＳＣＤＮＴ...     

雪旺氏细胞植入Dacron人造管修复周围神经缺损的实验研究

用自体或异体雪旺氏细胞植入Ｄａｃｒｏｎ管，移植修复大鼠坐骨神经缺损，术后７、１５、３０天取材进行光镜观察，见植入自体雪旺氏细胞组，再生轴突数与再生轴恢复率均优于不植入雪旺氏细胞组和异体雪旺氏细胞组，与自体神经全转回值组结果相近。实验表明：自体雪旺氏细胞植入到渗透作用好、无排斥反应的人造Ｄａｃｒｏｎ管中，同时加入自体血浆作营养支持物，对周围神经再生有较好的促进作用，可望有临床应用前景。     

LPS对大鼠雪旺氏细胞iNOS表达的影响

目的：探讨内毒素脂多糖（Lipopolysaccharide,LPS）对大鼠雪旺氏细胞（Schwann cells,Scs）诱导型一氧化氮合酶（Inducible nitric-oxide synthase,iNOS）基因表达及一氧化氮（Nitric oxide,NO）生成的影响。方法：用不同浓度（1、10、100μg/ml）和同一浓度不同时间（1、2、4、6小时）的LPS刺激雪旺氏细胞,分别用RT-PCR和亚硝酸盐含量测定观察细胞iNOS mRNA的表达量和细胞培养液中亚硝酸盐的水平,同时用免疫荧光细胞化学染色检测iNOS的细胞定位。结果：用LPS10μg/ml刺激2小时后,iNOS mRNA的表达增加,4小时表达活性最高。细胞上清中的亚硝酸盐含量高峰在6小时。免疫细胞化学证明LPS诱导雪旺氏细胞iNOS的表达定位在胞浆。结论：LPS可在转录水平上诱导雪旺氏细胞iNOS mRNA表达,促进NO的合成,提示雪旺氏细胞在周围神经系统炎症过程中可能发挥免疫调节作用。     

体外培养人胎儿雪旺氏细胞的增殖及其细胞动力学研究

新鲜和液氮保存3个月的人胎儿雪旺氏细胞体外培养8天,细胞数量增加一倍,培养液中加入二丁基环磷酸腺苷和牛脑垂体浸出液,细胞增倍时间缩短近一倍.流式细胞计测定结果显示,培养早期,S期、G2+M期细胞所占比例<5%,随着培养时间的延长,其比例逐渐增加,第6天达高峰,环磷酸腺苷和垂体浸出液作用3天,S期、G2期+M期比例达15%.实验结果表明:人胎儿雪旺氏细胞在体外增殖缓慢,环磷酸腺苷和垂体浸出液能刺激雪旺氏细胞分裂;冷冻复苏后的雪旺氏细胞其生长特征以及对环磷酸腺苷和垂体浸出液的反应与新鲜细胞相同.     

雪旺氏细胞在周围神经损伤修复中的作用

雪旺氏细胞是周围神经系统特有的一种细胞，由Schwann氏(1839)首先发现并命名。多年研究表明，雪旺氏细胞在周围神经修复中起着功能性的角色，是周围神经微环境的重要成分，促进轴突生长的重要因素。Fansa等发现，将体外培养的雪旺氏细胞植入去细胞成分的骨路肌桥接鼠坐骨神经缺损，显促进了神经再生。wejdner等，实验证明将雪     

LPS对大鼠雪旺氏细胞TNF-α合成和释放的影响

目的：探讨内毒素脂多糖（lipopolysaccharide,LPS）的诱导作用对大鼠雪旺氏细胞肿瘤坏死因子α（tumor nec-rosis factor-α,TNF-α）的表达。方法：不同浓度,不同时间用LPS刺激雪旺氏细胞,用酶联免疫吸附实验（ELISA）分别检测细胞胞液和上清中分泌的TNF-α的表达量,同时用间接免疫荧光细胞化学染色检测TNF-α的细胞定位。结果：用LPS10μg/ml刺激后2小时能显著促进雪旺氏细胞浆内TNF-α的表达,同时也检测到培养液上清中有TNF-α的释放。结论：细菌的致病因子LPS的诱导确能促进雪旺氏细胞高效表达和分泌TNF-α,从而为雪旺氏细胞作为免疫活性细胞在周围神经系统中发挥免疫调节作用提供初步依据。     

体外培养人胎儿雪旺氏细胞的增殖及其细菌动力学研究

新鲜和液氮保存３个月的人胎儿雪旺氏细胞体外培养８天。细胞数量增加一倍，培养液中加入二丁基环磷酸腺苷和牛脑垂直体出液，细胞增倍时间缩短近一倍。流式细胞计测定结果显示，培养早期，Ｓ期，Ｇ２＋Ｍ期细胞所占比例〈５％，随着培养时间的处长，其比例逐渐增加，第６天达高峰，环磷酸腺苷和垂体浸出液作用３天，Ｓ期，Ｇ２期＋Ｍ期比例达１５％。     

抗人活化B淋巴细胞单克隆抗体制备及鉴定

自儿童手术摘除的新鲜扁桃体分离人Ｂ淋巴细胞，经ＰＭＡ（佛波醇）激活后得到人活化Ｂ淋巴细胞，用于免疫ＢＡＢＬ／Ｃ小鼠后，取免疫小鼠之脾细胞与小鼠骨髓瘤细胞ＳＰ２／０融合，融合后细胞于含ＨＡＴ－ＩＭＤＭ完全培养基的２％甲基纤维素半固体培养基选择生长，经细胞酶联免疫吸附（ＣＥＬＩＳＡ）筛选间接免疫荧光流式细胞仪鉴定，获培养上清对活化Ｂ细胞及３Ｄ５细胞株细胞反应阳性，而Ｊｕｒｋａｔ细胞株细胞反应阴必的杂交     

Cryopreservation of cytological specimens for immunocytochemistry.

A method has been established for storage and preservation of cytological specimens in liquid nitrogen and further processing for immunocytochemistry as smears prepared from thawed cells or cryo-sections of frozen cell pellets. For the experiments cultured cells of a T-lymphoblastic leukemia cell line (ATCC CCL 119) and blood cells of the buffy coat of healthy humans were treated with a cryo-solution (fetal calf serum +5% dimethylsulfoxid) and after freezing stored in liquid nitrogen. Alternatively, cells preincubated with cryo-solution followed by suspension in fetal calf serum without cryo-additive were frozen and stored in liquid nitrogen for the production of cryo-sections. Indirect immunofluorescence and alkaline phosphatase--antialkaline phosphatase based immunoreactions were performed for the decoration of various surface antigens with a panel of monoclonal antibodies. All immunoreactions were repeated at least three times and the stored cell preparations were investigated after different periods of storage (up to four months). The immunoreactions of fresh cells in suspension (which were used as controls) were comparable with those of cryopreserved cells, e.g. cells on smears after thawing and on cryo-sections of cell pellets. The strongest immunoreactions were achieved on fixed cryo-sections. The maintenance of cell morphology of smears from cryopreserved cells was slightly better than of cells from cryo-sections. In our hands the preparation of cell pellets, which are suitable for the storage in liquid nitrogen and the production of cryosections, is a very useful method for immunocytochemical investigations of cytological specimens especially in situations where immunoreactions cannot be performed on fresh material.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of freeze/thawing process on cryopreserved equine umbilical cord blood-derived mesenchymal stem cells

The use of mesenchymal stem cells (MSCs)-derived equine umbilical cord blood in cell grafts transplantation is advantageous; therefore, preservation of these cells is of utmost importance in repair therapies. To evaluate the viability ratio of the MSCs obtained from equine umbilical cord blood after cryopreservation, umbilical cord blood obtained from nine 46–48-week-old foals were purified for harvesting MCs. The purified cells were frozen from the first to tenth passages and stored in liquid nitrogen. After thawing, the cell viability was assessed through trypan blue staining procedure. The highest viability (>80%) ratio was observed with the cells derived from the first passage in 1 and 8?weeks after cryopreservation. However, the viability of cells was dependent on the passage used for cryopreservation. Results in this study demonstrated that equine umbilical cord blood stem cells could successfully be frozen and stored in liquid nitrogen for 8?weeks without significant change in the characterization of the cells cryopreserved as regards their viability, growth ability, and differentiation potential.     

冷冻预处理温度对胎兔许旺细胞活性的影响

背景：许旺细胞作为周围神经损伤修复的重要桥接材料,其活性对临床修复周围神经损伤成功与否具有重要影响。 目的：观察不同维持温度冷冻预处理超深低温保存对胎兔许旺细胞活性的影响。 方法：设计胎兔许旺细胞冷冻维持温度为-30~-70 ℃,每间隔-5 ℃为一组,以10%二甲基亚砜为低温保护剂,对胎兔许旺细胞进行上述温度冷冻预处理,液氮中保存48 h,快速复温后继续培养48 h,透射电镜观察细胞超微结构改变,MTT法和³H-TdR掺入法检测细胞活性。 结果与结论：透射电镜下见-45 ℃处理的细胞超微结构良好,其余各温度组细胞均出现细胞器肿胀、坏死等轻重不同的冷冻损伤表现。MTT法和³H-TdR检测结果均显示-45 ℃冷冻预处理对许旺细胞的生长抑制率最低,分别为(3.83±0.56)%、(4.41±0.71)%,和其余各温度组之间相比,差异有显著性意义(P < 0.05)。提示-45 ℃是胎兔许旺细胞冷冻预处理的最佳维持温度值,对细胞活性影响最小,可较好保持其生物学活性。     

Cryopreservation,survival and function of intrastriatal fetal mesencephalic grafts in a rat model of Parkinson's disease

Summary In the present study we quantitatively assessed to what extent freeze-storage at liquid nitrogen temperature influences the survival and function of fetal mesencephalic grafts in the dopamine-depleted rat striatum. Ventral mesencephalic (VM) tissue was dissected from rat fetuses and stored overnight in a preservative medium at 4 °C (hibernation). It was grafted intrastriatally either as a fresh cell suspension or was frozen as tissue fragments or as a cell suspension after stepwise incubation in ascending concentrations of dimethyl-sulphoxide. Following a cryopreservation interval of 80 days in liquid nitrogen, the frozen samples were rapidly thawed, rinsed, and grafted. Cellular viabilities of graft cell suspensions, as assessed by ethidium bromide/acridine orange staining, were decreased from 90% in fresh tissue to 38-35% in frozen and thawed tissue. Amphetamine-induced turning behavior at 6 weeks post-grafting was significantly attenuated in hosts that had received fresh grafts or grafts that were frozen as tissue fragments. Tyrosine hydroxylase-(TH-) immunocytochemistry of recipient brains revealed significant decreases in TH-positive graft cell numbers in rats grafted with cryopreserved tissue (38–42% of fresh tissue). Moreover, the dye exclusion viability of thawed VM tissue was found to accurately predict the subsequent graft survival. There was no difference with respect to graft cell numbers between the two freezing methods employed, though block storage seems to be more simple from a practical point of view. The present study indicates that freezing in liquid nitrogen may be a feasible method for long-term storage of fetal neural tissue for grafting, although a marked decrease in graft survival and function of cryopreserved tissue must be taken into account.Present address: Dept. of Medical Physiology     

Survivability of rabbit amniotic fluid-derived mesenchymal stem cells post slow-freezing or vitrification

This work aimed to evaluate the effect of two distinct cryopreservation procedures - conventional slow-freezing and vitrification, on survivability and mesenchymal marker expression stability of rabbit amniotic fluid-derived mesenchymal stem cells (rAF-MSCs). Cells at passage 2 were slowly frozen, using 10% of dimethylsulfoxide, or vitrified, using 40% of ethylene glycol, 0.5 M sucrose and 18% Ficoll 70. After three months storage in liquid nitrogen, viability, chromosomal stability, ultrastructure, surface and intracellular marker expression and differentiation potential of cells were evaluated immediately post-thawing/warming and after additional culture for 48–72 h. Our results showed decreased (P ≤ 0.05) viability of cells post-thawing/warming. However, after additional culture, the viability was similar to those in fresh counterparts in both cryopreserved groups. Increase (P ≤ 0.05) in the population doubling time of vitrified cells was observed, while doubling time of slow-frozen cells remained similar to non-cryopreserved cells. No changes in karyotype (chromosomal numbers) were observed in frozen/vitrified AF-MSCs, and histological staining confirmed similar differentiation potential of fresh and frozen/vitrified cells. Analysis of mesenchymal marker expression by qPCR showed that both cryopreservation approaches significantly affected expression of CD73 and CD90 surface markers. These changes were not detected using flow cytometry. In summary, the conventional slow-freezing and vitrification are reliable and effective approaches for the cryopreservation of rabbit AF-MSCs. Nevertheless, our study confirmed affected expression of some mesenchymal markers following cryopreservation.     

T-cell subset analysis of cryopreserved human peripheral blood mononuclear cells

A criticism of current techniques for monitoring changes in T-cell subset numbers over extended periods in individuals with disease states in which such changes might provide insight is the fact that serial samples taken are usually analysed fresh and therefore not in the same assay. To try to overcome this problem we have stored peripheral blood mononuclear cells frozen in liquid nitrogen and thence examined their ability to form sheep red blood cell (E) rosettes and to label with OK monoclonal antibodies. Results obtained show that cell viabilities following freezing and T-cell subset analysis of E-rosette positive cells are no different when fresh or frozen and subsequently thawed peripheral blood mononuclear cells are used.     

Plaque-forming cell response of pokeweed mitogen stimulated frozen human lymphocytes

The plaque-forming cell (PFC) response of pokeweed mitogen (PWM) activated fresh or frozen human peripheral blood lymphocytes (PBL) was monitored by the protein A hemolytic plaque assay. Fresh PBL and PBL stored in nitrogen for 7 days to 8 years were tested. On the basis of our preliminary results we conclude that cryopreserved cells secrete the same amounts of immunoglobulin (Ig) as freshly prepared cells.     

Myelinated, but not unmyelinated axons, reversibly down-regulate N-CAM in Schwann cells

Summary There is evidence from chicks and mice that N-CAM expression in Schwann cells is subject to significant regulation during development and following injury. In the present work, rat sciatic nerve and immunohistochemical methods have been used to study developmental and injury-related modulation of N-CAM in Schwann cells, using cell type specific markers to identify different Schwann cell populations, and cell counting to quantify their size. The study has sought to determine unambiguously whether immature Schwann cells in developing nerves and denervated Schwann cells in injured adult nerves express surface N-CAM, and has investigated the temporal relationship between the gradual loss of surface N-CAM and the differentiation of myelin-forming Schwann cells, monitored by the sequential appearance of the glycolipid galactocerebroside and the myelin-specific protein P₀. Further points examined are whether this down-regulation of N-CAM is rapidly reversible following loss of axonal contact, and whether N-CAM reappearance in Schwann cells depends on protein synthesis.In nerves from 17- to 18-day embryos, 90% of the Schwann cells, identified with Ran-1 antibodies, expressed surface N-CAM. In nerves from newborn rats many cells are in the early stage of myelin synthesis and therefore express galactocerebroside, although they have not yet acquired P₀. Suspension staining of dissociated cells from this nerve showed that 92% of the galactocerebroside-positive cells were also N-CAM positive. In suspension staining of nerves from 5-day, 10-day and adult rats, P₀-positive cells were essentially N-CAM negative. If, however, cells from 10-day nerves were placed in culture and immunostained after, 3, 6, 9 and 24 h, N-CAM appeared in the P₀-positive cells that had formed myelinin vivo. The percentage of P₀-positive cells that also expressed N-CAM at these time points was 10, 28, 56 and 92%, respectively. Cell division was not a prerequisite for N-CAM reappearance which was, however, blocked by cycloheximide, an inhibitor of protein synthesis. Schwann cells in transected adult sciatic nerves in which regeneration was prevented, expressed surface N-CAM 2 months after injury, indicating that in the absence of axonal contact Schwann cells express N-CAM indefinitely.The results indicate that in myelin-forming Schwann cells N-CAM synthesis is continuously suppressed by ongoing axonal signals. Thus axon-Schwann cell signals are involved not only in up-regulation but also in reversible down-regulation of Schwann cell molecules.     

Nitroblue tetrazolium (NBT) activity in human leucocytes after freezing

Human peripheral blood leucocytes (neutrophil-rich) were collected either with heparin or acid citrate dextrose, frozen with dimethyl sulphoxide at a controlled rate, stored in liquid nitrogen at--196 degrees C and reconstituted with a solution containing dextran. After reconstitution, 20.2% of cells (in absolute numbers 1 in 5 fresh cells) showed a strongly positive nitroblue tetrazolium (NBT) reaction. The quantitative NBT test confirmed the synthesis of formazan/10(6) reconstituted neutrophilsa s15% of the fresh capacity. A slow titration reconstitution method for cells did not improve the functional capacity of thawed leucocytes as judged by the NBT test. When comparing anticoagulants, heparin increased the post-reconstitution cell yields after freezing and increased the absolute number of reconstituted cells capable of developing a positive NBT reaction.     

感觉神经和运动神经Schwann细胞的培养研究

为了建立应用于神经组织工程的感觉神经和运动神经的 Schwann细胞的体外培养方法 ,采用联合酶消化法对 SD乳鼠后根神经和股神经运动支的 Schwann细胞进行了培养 ,并经抗 S10 0荧光染色鉴定和双抗体夹心间接 Elisa法测量两种 Schwann细胞培养基中 NGF的表达。结果表明 ,两种培养细胞经荧光染色证明均为 Schwann细胞 ,细胞纯度均超过 95 % ,光镜观察未见形态学差异 ,但 NGF的表达量和表达模式均有显著性差别 (P<0 .0 5 )。提示 ,本实验方法可以获得高纯度的感觉神经和运动神经的 Schwann细胞 ,两者的生物学功能有一定差异。