确定小鼠肝脏中的胆汁密度
Summary
我们提出了一种相当简单和敏感的方法,用于准确定量小鼠肝脏中的胆管密度。该方法有助于确定遗传和环境修饰剂的影响,以及潜在疗法在胆汁疾病小鼠模型中的有效性。
Abstract
老鼠被广泛用作研究胆汁疾病的模型。为了评估胆汁系统的发展和功能,使用了各种技术,包括血清化学、组织学分析和特定标记物的免疫染色。虽然这些技术可以提供有关胆汁系统的重要信息,但它们通常不能显示整个肝脏胆管 (BD) 发育缺陷的完整情况。部分原因在于小鼠肝脏能够强大的能力排出胆汁,即使在胆汁发育有显著损害的动物中也是如此。在这里,我们提出了一个简单的方法,以计算与每个门户静脉 (PV) 相关的 D 的平均数量,这些部分涵盖突变/转基因小鼠的所有叶。在这种方法中,肝脏以立体的方式安装和分割,以方便各种基因型和实验条件之间的比较。BD通过细胞角素染色胆汁的光学显微镜进行识别,然后除以肝脏部分的PV总数。例如,我们展示了这种方法如何能够清楚地区分野生型小鼠和Alagille综合征的小鼠模型。这里介绍的方法不能替代可视化胆汁树三维结构的技术。然而,它提供了一种简单而直接的方法,定量评估BD的发展和小鼠的导管反应形成程度。
Introduction
胆汁树是哺乳动物肝脏的关键部分,允许胆汁从肝细胞进入肠道。内肝胆管(BDs)是由胆囊形成,通过Notch和TGF+信号1,2与双电位肝细胞区分。正确规范和承诺胆汁及其组装成成熟的BD对肝胆内树的发展至关重要。随着肝脏在发育过程中或器官再生时生长,胆汁系统需要沿着肝脏发展,以确保适当的胆汁排水。此外,一些综合和非合成性疾病导致肝内3的缺乏。此外,一些急性和慢性肝病引起所谓的肝脏导管反应,这些反应被定义为存在大量细胞,这些细胞表示胆道标记,但不一定来自胆道细胞或形式专利BD4.在多系统紊乱阿拉吉勒综合征(ALGS),单体不全的诺奇配体锯齿1(JAG1)导致不良的BD形成和胆汁症5,6。我们的实验室最近证明,以前生成的Jag1杂物小鼠线7是ALGS 8中BD贫乏的动物模型。在这个ALGS的小鼠模型中,胆小板仍然存在。然而,他们未能承诺纳入成熟的专利BD8。因此,在BD缺乏模型中分析肝脏需要的不仅仅是胆汁的明显存在或缺乏。准确评估成熟性BD在肝脏中存在的程度非常重要。
在解剖病理学中,有公认的定量方法来评估BD是否存在9。例如,对人类患者ALGS的研究通常通过分析每个肝脏活检至少10个门户血管9,10来量化BD到门户静脉(PV)比率。分析形状和整体存在或缺乏专利的BD,结合血清化学,可以提供关于小鼠11,12,13的BD发展的宝贵信息。然而,小鼠可能失去大量的BD,只有血清胆红素水平8略有增加。因此,一种定量方法,评估每个PV存在的BD数量,可以提供更直接的测量在小鼠的BD不足程度。在最近的一份报告中,我们量化了所有肝瓣中每PV的BD数,并报告Jag1+/+动物8的BD与PV比显著下降。在分析过程中,我们注意到,尽管炎症反应和管道反应的程度有显著差异,但BD与PV比并没有表现出太大的变异性8。此外,对BD与PV比的量化使我们能够证明,在Jag1+/+动物中去除一个糖基转移酶基因Poglut1副本可以显著改善其BD不足8。在Jag1+/+背景下,血管平滑肌细胞中Poglut1的有条件损失会导致 BD 数量逐渐增加,这是适度的 (20-30%)在P7,但在成人8变得突出。再次,这项技术允许我们证明,即使在P7,这些动物的BD密度的增加是统计显著。值得注意的是,通过树脂铸造分析,也验证了4个月大时这种基因型的BD密度增加。8这些观察和其他报告测量了不同ALGS小鼠模型14、15的BD密度,这促使我们把这种方法纳入我们的整体策略,以分析各种突变体中的胆汁缺陷和转基因小鼠。
在这里,我们详细介绍了一个简单的技术,可用于检查小鼠肝脏疾病模型中的BD缺乏程度(图1)。在此方法中,与胆小球菌标记物 (CK) 8 和 CK19 (下到广谱 CK, wsCK) 共同染色用于可视化小鼠肝脏中的 BD 和未合并的胆汁。对α平滑肌活动蛋白(αSMA)的抗体被添加到染色中,以标记血管。系统分析涵盖所有肝叶的一节中的BD与PV比,确保对每种基因型分析大量的PV。由于我们的方法依赖于在二维图像中量化 BD 和 PV,因此它不适合研究给定突变对胆汁树的 3D 结构的影响或小胆管的完整性。然而,它为调查人员提供了一个简单而客观的策略,以评估小鼠的胆汁发育情况。
Protocol
Representative Results
Discussion
小鼠BD发育与修复分析是研究胆囊性疾病发病机制和机理的重要工具。此外,新疗法的发展部分取决于建立可重复的,最好是可量化的表型。小鼠模型中的电流表示通常涉及血清化学、肝脏信息学和细胞类型特定标记物的免疫染色。虽然这些技术产生了关于胆管系统的结构和功能的宝贵信息,但它们不能直接测量给定基因操作对发育系统数量的影响。在解剖病理学中,通过分析活检第9…
Declarações
The authors have nothing to disclose.
Acknowledgements
作者感谢美国国家卫生研究院(R01 GM084135和R01 DK109982)的支持,来自德克萨斯州医疗中心消化疾病中心的试点/可行性奖,由NIH P30 DK56338颁发,阿拉吉勒综合征加速器奖来自医学基金会
Materials
| Isothesia (Isoflurane) | Henry Schein | 11695-6776-2 | |
| Desiccator | Bel-Art | 16-800-552 | |
| 10% PFA | Electron Microscopy Sciences | 15712 | |
| 50mL tube | ThermoScientific | 339653 | |
| 70% Ethanol | Decon Laboratories | 2401 | |
| 95% Ethanol | Decon Laboratories | 2801 | |
| 100% Ethanol | Decon Laboratories | 2701 | |
| HistoChoice | VWR Life Sciences | H103-4L | clearing agent |
| Omnisette Tissue Cassette | Fisher HealthCare | 15-197-710E | |
| Macrosette | Simport | M512 | |
| Paraplast X-TRA | McCormick Scientific | 39503002 | Parrafin |
| Tissue Mold | Fisher Scientific | 62528-32 | |
| Microtome | Microm | HM 325 | |
| Superfrost Plus Microscope Slides | Fisher Scientific | 12-550-15 | |
| Xylene | Fisher Scientific | C8H10 | |
| Tris-Based Antigen Retrieval | Vector Laboratories | H-3301 | |
| Pressure Cooker | Instant Pot | Lux Mini | |
| Mini Pap Pen | Life Technologies | 8877 | |
| Polyoxyethylene 20 Sorbitan Monolaurate (Tween-20) | J.T. Baker | X251-07 | |
| Octyl Phenol Ethoxylate (Triton-X-100) | J.T. Baker | X198-07 | |
| Normal Goat Serum | Jackson Immunoresearch | 005-000-121 | |
| anti-CK8 | Developmental Studies Hybridoma Bank | TROMA-I | Antibody Registry ID AB531826 |
| anti-CK19 | Developmental Studies Hybridoma Bank | TROMA-III | Antibody Registry ID AB2133570 |
| anti-αSMA | Sigma Aldrich | A2547, Clone 1A4 | |
| anti-rat-Alexa488 | ThermoFisher | A21208 | |
| anti-mouse-Cy5 | Jackson Immunoresearch | 715-175-151 | |
| DAPI | Vector Laboratories | H-1000 | |
| 22×50 micro cover glass | VWR Life Sciences | 48393 059 | |
| Fluorescence Microscope | Leica | DMI6000 B | |
| Kimwipes | Kimtech Science | 05511 | |
| VECTASHIELD | Vector Laboratories | H-1000 | Antifade Mounting Medium |
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