我们描述了一个体外测定模型囊附着, 第一步胎盘形成。该协议展示了小鼠 allantoides 在固定化α4β1整合素上的解剖和外植体培养。尿附件是在预定的时间点显微镜下评估的。
胎盘对哺乳动物胚胎的生长发育至关重要。由于这个原因, 许多基因的改变和环境的侮辱, 扰乱胎盘的发展或功能可能导致早孕损失的小鼠和人类。然而, 简单的体外检测对胎盘形成的潜在影响是缺乏的。在这里, 我们的重点是建模的第一步和关键步骤的胎盘形成, 其中包括附着的尿的绒毛膜。我们描述了一种快速评估囊外植体附着在固定化α4β1整合素上的方法, 它是一种 chorio 模拟的基底。这种体外方法可以对不同连续时间点的多个尿的附着和扩散行为进行定性评估。该协议可用于调查有针对性的小鼠突变, 药物, 或各种环境因素的影响, 已与妊娠并发症或胎儿损失的尿附着在前体内。
胎盘在子宫环境中的胚胎生长发育是必不可少的。它构成了胎儿和母体循环之间的氧气、代谢物和养分交换的界面, 也是内分泌和免疫器官的功能。任何内生或外源性侮辱, 损害胎盘发育可能导致宫内发育迟缓, 胎儿的损失, 或怀孕并发症, 在小鼠和人类的1。虽然导致胎盘生理异常的靶向小鼠突变的数量继续增加2, 但目前在小鼠基因组信息学 (凡陀) 网站上列出的219种基因型是 (http://www.informatics.jax.org/vocab/mp_ontology/MP:0010038), 许多这些表型从机械的角度看不清楚。除了基因改变, 小分子药物, 单克隆抗体, 毒素, 病原体, 过量代谢物, 或各种环境因子可能影响胎盘发育和功能3,4,5,6,7. 然而, 简单的体外分析了胎盘发育中的模型关键步骤是稀缺的。
小鼠胎盘发育在早期妊娠开始, 当尿 (脐带的发育前体) 从胚的后端出现, 作为一个芽, 生长向绒毛膜的8。Chorioadhesive 细胞在囊芽的外层斡旋在绒毛膜 (囊 “融合”) 的表面上的附着和传播尿。绒毛膜随后折叠成绒毛进入其中尿的血管生长形成迷宫, 内部胎盘层在那里营养和氧气被交换在严密并列的母体血液窦和胚胎血管之间9 ,10。
尿对绒毛膜的附着是迷宫形成的初始和关键步骤, 而这一过程中的缺陷是妊娠1中最常见的胚胎致死原因之一。虽然已经描述了许多鼠标突变体, 但囊附件无法出现在10, 并且凡陀数据库当前列出了108个以异常囊融合为特征的鼠标突变体 (http://www.informatics.jax.org/vocab/mp_ontology/MP:0002824), 血管细胞黏附分子之间的相互作用 molecule-1 (VCAM-1, 表达囊胚层) 和α4β1整合素 (表达在绒毛膜皮, 这是派生自外胚层) 似乎是必不可少的囊附件和融合11,12,13。全芒野型胚的免疫组织化学染色表明, VCAM-1 在囊茎远端2/3 处以大约胚胎日 (E) 7.513 (1-4 节阶段) 表达, 其表达仍然高在囊附件和-融合11,12期间。囊附着于绒毛膜的失败通常通过子宫芽的组织学分析来检测。然而, 尿大小是生理上高度可变的在之间, 甚至在同一发育阶段的凋落物14, 和尿只能附加到绒毛膜当它已经达到足够的大小, 使身体接触。反射这自然可变性, 囊附件发生在 ~ e 8.0 和 e 9.0在子宫内, 并且一个统计地可靠评估这个过程由组织学是依赖于分析许多conceptuses 在适当的发育阶段获得足够的标本。
在这里, 我们描述一种方法来评估囊附件前子宫, 不太依赖于尿大小。我们展示了小鼠胚胎的解剖和他们的 allantoides 从怀孕的老鼠的子宫〜8天后 coitum (dpc; dpc 0.5 指定阴道插头的检测), 并随后培养尿外植体的固定α4β1整合.该方法能够对多尿外植体在不同的连续时间点上的附着和扩展行为进行快速、实用的评价。该协议可用于筛选目标突变、药物或各种环境因素对尿附着体的影响ex 体内。
在血清的存在, 这是一个丰富的来源, pro-adhesive 细胞外基质分子, 如纤维连接蛋白, 尿植体将欣然附加到各种塑料, 玻璃, 或过滤表面9,16。因此, 如果进行的试验的目的是专门研究基因修饰或任何其他治疗对固定化α4β1尿附着的影响, 就必须阻止非特异性结合位点 (例如, 用牛血清白蛋白) 涂层后的表面与整合素和前孵化与含血清的媒体。
<p class="jo…The authors have nothing to disclose.
这项工作得到了德意志 Forschungsgemeinschaft SFB688 (对司法部) 的支持。
C57BL/6J wildtype mice | The Jackson Laboratory | Stock No: 000664 | |
70 % (v/v) Ethanol | VWR International | 930031006 | |
Standard pattern forceps | Fine Science Tools | 11000-12 | Forceps used to open the abdominal cavity. |
Micro dissecting forceps | Fine Science Tools | 11254-20 | Dumont # 5 medical biology forcepts with fine, sharp tip. |
Fine scissors | Fine Science Tools | 14094-11 | Straight blades. |
Spring scissors | Fine Science Tools | 15012-12 | Noyes spring scissors with 14 mm blades for the dissection of uterus buds. |
Microspoon | Carl Roth | AT18.1 | 5 mm Spoon diameter. |
Microtiter plates | ibidi | 81501 | We use uncoated, sterile angiogenesis slides (internal volume 50 µL) with a hydrophobic surface that is not tissue-culture treated to reduce non-a4b1-mediated binding to plastic. |
10 cm dish | Nunc | 150350 | Sterile tissue culture dishes. |
3.5 cm dish | Nunc | 150288 | Sterile tissue culture dishes. |
Large orifice pipette tips | Biozym | VT0140X | Low binding pipette tips, 200 µL. |
a4b1 integrin | R&D Systems | 6054-A4 | Murine a4b1 integrin recombinantly expressed and purified from a Chinese hamster ovary cell line. |
Dulbecco's Phosphate Buffered Saline (PBS) | Sigma Aldrich | D8537 | Without Ca2+ and Mg2+. |
Dulbecco’s Modified Eagle Medium (DMEM) | PAN Biotech | P04-03600 | The formulation contains 4.5 g/L glucose, 110 mg/L sodium pyruvate and 3.7 g/L NaHCO3 but no L-glutamine, which is added separately. |
Penicillin/Streptomycin | Gibco (ThermoFisher Scientific) | 15140-122 | 100 x (10,000 U/mL Penicillin and 10,000 µg/mL streptomycin) stock solution. Prepare and store aliquots at -20 °C to avoid freeze/thaw. |
L-Glutamine | PAN Biotech | P04-80100 | 100 x (200 mM) Stock solution. Prepare and store aliquots at -20 °C to avoid freeze/thaw. |
Fetal bovine serum | Biochrom | S 0115 | We use heat-inactivated FBS (heated to 56 °C for 30 min with mixing to inactivate complement). |
Bovine serum albumin (BSA) | Sigma Aldrich | A7030 | We use protease- and fatty acid-free albumin. Prepare a 0.1 % (w/v) solution in DMEM. Sterile filter the solution through a disposable cell culture filter with a 0.22 µm pore size and low protein-binding membrane, and store aliquots at -20 °C. |
para-Formaldehyde | Carl Roth | 0335.2 | To make a formaldehyde solution in PBS, weigh para-formaldehyde powder in a ventilated hood, and add it to PBS preheated to ca. 60 °C in a beaker on a stir plate. Add 1 N NaOH dropwise until solution clears. Let solution cool to room temperature, and filter through 0.22 mm filter syringe. Adjust pH with diluted HCl to ca. 6.9, and adjust to final volume with PBS. We aliquot and freeze the solution, but it can also be stored at 4 °C for approximately four weeks. |
Triton X-100 | Sigma Aldrich | X100 | Use wide-orifice pipette tips to handle undiluted Triton X-100. |
Normal goat serum | Sigma Aldrich | G9023 | To block non-specific binding of antibodies in immunofluorescence analyses. |
a-CD31 Antibodies | BD Biosciences | 550274 | Purified rat anti-mouse monoclonal antibodies, clone MEC 13.3. |
Secondary goat anti-rat antibodies | Thermo Fisher | A-11006 | Goat anti-rat IgG (heavy and light chains), cross-adsorbed, fluorescently labeled with Alexa Fluor 488. Other fluorescent labels are also possible. |
Mowiol 4-88 | Sigma Aldrich | 81381 | Mounting medium for cytochemistry. MW ~31,000 |
Labovert | Leitz | Labovert | Inverted phase contrast microscope equipped with a 4 x and 10 x objective for somite pair counting. Other phase contrast microscopes (such as those that are routinely used in tissue culture) are also suitable. |
M80 | Leica Microsystems | M80 | Stereomicroscope with 8 : 1 zoom range (yielding a magnification between 7.5 x and 60 x) for embryo and allantois dissection. |
DM4000B | Leica Microsystems | DM4000B | Microscope system for histology with LED illumination. We use HCX PL FLUOTAR 5 x/0.15 and HC PL FLUOTAR 10 x/0.30 objectives. Other microscopes equipped phase contrast and fluorescence optics can be used to score allantois attachment. |
Digital camera | JVC | KY-F75U | 3-CCD digital capture camera attached to the DM4000B LED microscope. We use Diskus software (Hilgers) to operate both the microscope and the camera. |
Confocal microscope | Leica Microsystems | SP5 | Confocal microscope for higher-resolution imaging of endothelia in the vascular plexus of allantois explants. Immunofluorescence images were taken with a 40 x objective. |