坐骨神经外植块对脊神经节的感觉神经元高亲和力神经生长因子受体表达的影响

用细胞培养及trkA免疫组化染色方法，观察了坐骨神经外植块及巨噬细胞和雪旺氏细胞条件培养基对胚鼠脊神经节感觉神经元高亲和力神经生长因子受体表达的影响。结果显示：各组感觉神经元均产生免疫阳性反应，雪旺氏细胞条件培养基和巨噬细胞条件培养组免疫反应强度与对照组相同，联合培养组免疫反应为强阳性，与巨噬细胞条件培养组相比差别高度显著（P＜0.005）。免疫反应阳性神经元可分为2类：一类形状为圆形或椭圆形，另一类为多角形。实验组神经元和非神经元生长状况明显优于对照组。本研究结果提示：坐骨神经的溃变轴突有促进脊神经节内感觉神经元trkA表达的作用;雪旺细胞条件培养和巨噬细胞条件培养组的某些因子可直接或间接地维持感觉神经元的生存，但不促进其trkA的表达。     

Alumina particles influence the interactions of cocultured osteoblasts and macrophages.

The purpose of the current study was to evaluate the effects of alumina particles on secretion of several cytokines involved in bone resorption in cocultures of macrophages and osteoblasts. To distinguish the contribution of each individual cell type, we have established a heterologous in vitro system that makes use of mouse J774 cells and primary cultured human osteoblasts. J744 cells decreased the production of TNF-alpha when they were cocultured with osteoblasts. Treatment of J744 cells with alumina particles increased TNF-alpha secretion, but the induction was lower when cells were cocultured with osteoblasts. Secretion of IL-6 by J744 cells was very low, and increased in the presence of osteoblasts. Alumina particles were only able to stimulate the release of IL-6 by J744 cells when cells were cocultured with osteoblasts. On the other hand, incubation of osteoblasts with alumina particles enhanced the release of IL-6 and GM-CSF. Coculturing osteoblasts with J744 cells induced them to release IL-6 and GM-CSF, and treatment with alumina further increased the secretion of both mediators by osteoblasts. According to these in vitro results, it seems rather plausible that alumina particles are able to initiate an inflammatory response in vivo.     

牙齿再生的研究

牙齿再生的研究是国内外学者们十分关注的课题，构建有生物活性的组织工程化牙齿一直是该项研究的热点所在。本文就牙齿再生的研究手段、研究策略等方面的最新进展进行综述，并对牙齿组织工程研究当前所面临的主要问题展开讨论。     

Structure and function of long-lived olfactory organotypic cultures from postnatal mice

The first synapse in the olfactory pathway mediates a significant transfer of information given the restricted association of specific olfactory receptor neurons with specific glomeruli in the olfactory bulb. To understand better how this connection is made and what the functional capacities of the participating cells are, we created a long-lived culture system composed of olfactory epithelium and olfactory bulb tissues. Using the roller tube method of culturing, we grew epithelium-bulb cocultures, explanted from 1-4-day-old Swiss Webster mice, on Aclar for periods ranging from 18 hr to 68 days. The explants flattened so that in some areas the culture was only a few cells thick, making individual cells distinguishable. From 107 cultures studied, we identified the following cell types by expression of specific markers (oldest culture expressing marker, days in vitro, DIV): olfactory receptor neurons (neural cell adhesion molecule, 42 DIV); mature receptor neurons (olfactory marker protein, 28 DIV); postmitotic olfactory receptor neurons and olfactory bulb neurons (beta-tubulin, 68 DIV); astrocytes (glial fibrillary acidic protein, glutamate/aspartate transporter, 68 DIV); olfactory horizontal basal cells (cytokeratin, 22 DIV). Neuronal processes formed glomeruli in 2-4-week-old cultures. We also recorded electro-olfactography responses to puffs of vapor collected over an odorant mixture containing ethyl butyrate, eugenol, (+) carvone, and (-) carvone from cultures as old as 21 DIV. These features of our olfactory culture system make this model useful for studying properties of immature and mature olfactory receptor neurons, pathfinding strategies of receptor axons, and mechanisms of information transfer in the olfactory glomerulus.     

Bone marrow stromal cells enhance differentiation of cocultured neurosphere cells and promote regeneration of injured spinal cord

Transplantation of bone marrow stromal cells (MSCs) has been regarded as a potential approach for promoting nerve regeneration. In the present study, we investigated the influence of MSCs on spinal cord neurosphere cells in vitro and on the regeneration of injured spinal cord in vivo by grafting. MSCs from adult rats were cocultured with fetal spinal cord-derived neurosphere cells by either cell mixing or making monolayered-feeder cultures. In the mixed cell cultures, neuroshpere cells were stimulated to develop extensive processes. In the monolayered-feeder cultures, numerous processes from neurosphere cells appeared to be attracted to MSCs. In an in vivo experiment, grafted MSCs promoted the regeneration of injured spinal cord by enhancing tissue repair of the lesion, leaving apparently smaller cavities than in controls. Although the number of grafted MSCs gradually decreased, some treated animals showed remarkable functional recovery. These results suggest that MSCs might have profound effects on the differentiation of neurosphere cells and be able to promote regeneration of the spinal cord by means of grafting.     

Clinical Assisted Reproduction: An Analysis of Spontaneous Hatching in a Human Endometrial Epithelial Coculture System: Is Assisted Hatching Justified?

Purpose: To evaluate spontaneous embryo hatching in an endometrial epithelial coculture system, and compare it with cases where coculture was performed because of maternal age, previous repeated implantation failures, or both. To clarify in which cases assisted hatching would be appropriate.Methods: Individual human embryos were cocultured on an endometrial epithelial cell monolayer until Day 6.Results: Blastocyst hatching rate at Day 6, depending on maternal age, was 9.1% (age <37 years) and 3.4% (age 37 years). However, blastocyst hatching rates depending on number of previous IVF failures were similar.Conclusions: Maternal age and previous implantation failures are factors affecting the ability of human embryos to reach the blastocyst stage in coculture. However, assisted hatching is not justified in these populations because of the absence of hatching rate differences between blastocysts obtained from these two groups and the control group.     

心肌细胞共培养诱导骨髓间充质干细胞向心肌样细胞分化

目的在体外以新生大鼠心肌细胞（CM）与骨髓间充质干细胞（MSCs）共同培养的方式模拟心肌微环境,研究MSCs分化为心肌细胞的机制。方法分离大鼠MSCs在体外培养纯化后进行细胞标记,将已标记的MSCs分别与搏动的CM、停止搏动的CM以及心肌细胞条件培养液混合培养。分别在共培养后第4、5天用免疫荧光染色检测MSCs细胞中的心肌特异性肌钙蛋白T（Troponin T）。结果与搏动的CM共培养后第4天MSCs出现自发收缩,与CM同步搏动并表达Troponin T,而在抑制心肌细胞搏动或缺乏与心肌直接接触的情况下MSCs未出现上述变化。结论说明在与CM直接接触的前提下,CM对MSCs的机械牵拉刺激为诱导MSCs分化为心肌细胞的必须条件。单纯的心肌细胞条件培养液则非关键因素。了解MSCs分化为心肌细胞的机制对于寻找适宜的细胞移植条件有重要指导意义。     

脂肪间充质干细胞对J774.1细胞的免疫调控

背景：近期研究发现脂肪间充质干细胞针对T细胞、B细胞和树突状细胞均有抑制免疫反应的能力,但对于其是否可以对巨噬细胞起到相应的免疫调控能力还不清楚。目的：观察脂肪间充质干细胞与J774.1细胞共培养后白细胞介素6和肿瘤坏死因子α的表达方法：将脂肪间充质干细胞按照2×10^7孔分别接种于transwel 的上层小室和24孔板中,再利用含1 mg/L脂多糖的培养液重悬J774.1细胞,将J774.1细胞接种到含脂肪间充质干细胞的transwel 下层小室和24孔板中,同时设立未激活J774.1细胞阴性对照组和脂多糖激活J774.1阳性对照组。培养48 h收集细胞样,提取RNA样本,荧光定量PCR法检测白细胞介素6、肿瘤坏死因子αmRNA 水平。 结果与结论：相对于单纯脂多糖激活的阳性对照组J774.1细胞,脂肪间充质干细胞与J774.1细胞的接触型混合培养可以明显降低J774.1细胞的白细胞介素6和肿瘤坏死因子α的表达量,而非接触共培养组中,只有白细胞介素6 mRNA 水平发生了明显的降低。以上结果表明脂肪间充质干细胞具有抑制脂多糖激活 J774.1细胞的免疫反应的能力。