原位胰腺癌小鼠模型的动态对比增强磁共振成像
Summary
The goal of this protocol is to apply dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) for orthotopic pancreatic tumor xenografts in mice. DCE-MRI is a non-invasive method to analyze microvasculature in a target tissue, and useful to assess vascular response in a tumor following a novel therapy.
Abstract
Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) has been limitedly used for orthotopic pancreatic tumor xenografts due to severe respiratory motion artifact in the abdominal area. Orthotopic tumor models offer advantages over subcutaneous ones, because those can reflect the primary tumor microenvironment affecting blood supply, neovascularization, and tumor cell invasion. We have recently established a protocol of DCE-MRI of orthotopic pancreatic tumor xenografts in mouse models by securing tumors with an orthogonally bent plastic board to prevent motion transfer from the chest region during imaging. The pressure by this board was localized on the abdominal area, and has not resulted in respiratory difficulty of the animals. This article demonstrates the detailed procedure of orthotopic pancreatic tumor modeling using small animals and DCE-MRI of the tumor xenografts. Quantification method of pharmacokinetic parameters in DCE-MRI is also introduced. The procedure described in this article will assist investigators to apply DCE-MRI for orthotopic gastrointestinal cancer mouse models.
Introduction
该方法的总的目标是要应用动态对比增强磁共振成像（DCE-MRI）对小鼠原位胰腺肿瘤异种移植物。 DCE-MRI是一种非侵入性的方法，通过监测MR对比的变化超过一定时间内注射后，以评估微脉管的目标组织。 DCE-MRI已经被用于诊断恶性肿瘤，并评估肿瘤对各种疗法1-4。定量DCE-MRI已经呈现高重复性5。定量的靶组织的磁共振造影剂的药代动力学参数，在注射造影剂前获得不同的时间点和T1地图获得的所有DCE-MR图像必须配准6。然而，由于在腹部呼吸和蠕动运动，定量的DCE-MRI已经具备了胃肠道肿瘤应用有限。
原位胰腺肿瘤模型已被用于评估胰腺肿瘤反应下的生物治疗和化疗7,8。原位肿瘤模型被认为是优于传统的皮下模型中，由于在原来的肿瘤部位的微环境被反射并由此人肿瘤对治疗的反应，可以更准确地预测。然而，小鼠胰腺位于腹部的左上象限，在小鼠中，以便定量的DCE-MRI的原位胰腺肿瘤异种移植物还未容易地实现。
我们已经建立了小鼠腹部肿瘤中的DCE-MRI的协议通过使用正交弯曲的塑料板，以防止从胸部区域9运动传递定影的肿瘤。通过这款主板所施加的压力是局部的腹部，并没有导致呼吸困难。一种自动化图像配准技术已经被验证为在自由呼吸模式腹部器官的DCE-MRI，但它执行effectivelY仅在目标地区缓慢移动，并定期10。动物的呼吸速率成像期间可变的，在腹部区域，以便物理约束将是必要的，以检索在原位胰腺肿瘤小鼠模型可靠的药物动力学参数。我们已经使用正交弯曲的塑料板DCE-MRI中11-13成功定量在原位胰腺肿瘤异种移植物的MR造影剂的药动学参数。在这里，我们提出了原位胰腺肿瘤模型的详细过程，对移植瘤小鼠和药代动力学参数量化的DCE-MRI。
Protocol
Representative Results
Discussion
我们已经介绍了原位胰腺肿瘤模型使用免疫缺陷小鼠，小鼠的DCE-MRI腹部肿瘤，以及其动力学参数量化的具体方法。在原位胰腺肿瘤模型中，必须将针插入胰尾时服用。如果成功的话，将细胞将被转移到胰头创建一个小疱。当施加一个垂直弯曲的塑料板，关键是要确认肿瘤位于下方板的上端。由于胰腺肿瘤附近至该膜片，所述基板也可以是不能够牢固地保持它，特别是当肿瘤大小小于5毫米的直径?…
Divulgations
The authors have nothing to disclose.
Acknowledgements
Authors thank Jeffrey Sellers to assist orthotopic pancreatic cancer mouse modeling. This work was supported by Research Initiative Pilot Awards from the Department of Radiology at UAB and NIH grants 2P30CA013148 and P50CA101955.
Materials
| Name of Material/ Equipment | Company | Catalog Number | Comments/Description |
| DMEM | Invitrogen | 11965-118 | |
| Fetal bovine serum | Harlan Laboratories | BT-9501 | |
| Betadine | Purdue products | 67618-153-01 | |
| 5-0 Prolene sutures | Ethicon | 8720H | |
| 9.4T MR scanner | Bruker Biospin Corporation | BioSpec 94/20 USR | |
| Gadoteridol | Bracco Diagnostics Inc | NDC 0270-1111-03 | |
| Micro-polyethelene tube | Strategic Applications, Inc | #PE-10-25 | |
| 30G blunt tip needle | Strategic Applications, Inc | 89134-194 | |
| Monitoring and gating system | SA instruments, Inc | Model 1030 | This is an MR compatiable system to measure resiratory rating and body temperature of small animals at the same time. |
| Syringe pump | New Era Pump Systems, Inc. | NE-1600 |
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