window chamber surgery in tumor cell injected mice for tumor growth visualization and imaging

小鼠的引导肿瘤接种和多模式成像

Tumor microvasculature is an important component of the tumor microenvironment that can be a target for therapy and a determinant of treatment response. In the preclinical setting, the microvasculature is typically studied using intravital microscopy in orthotopic or heterotopic window chamber animal models1,2. This has several advantages over histological studies since the imaging is done in live tissues and the tumor can be monitored longitudinally over several weeks or even months2,3. These studies can leverage the high-resolution imaging capabilities of intravital microscopy to study the delivery of therapeutics to the tumor4,5, the causes of treatment resistance6, and the response of the micro vessels to therapies such as antiangiogenic treatment7,8 and radiotherapy2,9.
Intravital microscopy clearly plays an important role in preclinical cancer research; however, how can tumor microenvironmental features be measured in the clinic? Microvascular information would be useful in the clinic for measuring blood supply and tumor cell hypoxia, which is important for determining treatment resistance in radiotherapy10, as well as the ability of the microvasculature to deliver chemotherapeutic agents to the surrounding tumor cells11. For example, in radiotherapy, spatial information on the structure and function of the tumor microvasculature may help personalize a patient&#39;s treatment plan by adjusting the fractionation schedule or by preferentially boosting the dose to avascular and likely hypoxic regions12.
Intravital microscopy can measure these important microvascular features since it has a very high resolution (&#956;m scale); however, its depth penetration into tissue is limited to several hundred microns or a few millimeters, at most making clinical implementation challenging. Indeed, there are some novel applications of intravital microscopy in the clinic13; however, these are still limited to examinations of near-surface level tissue such as the skin14 or mucosal/endothelial linings of various body cavities via flexible catheters/endoscopes15,16.
More commonly, the microvasculature is studied using imaging modalities such as CT17 or MRI18. These clinical imaging modalities can image to any depth within the body, but they have a much lower spatial resolution (mm scale). Thus, there is a need to bridge this resolution gap between preclinical intravital microscopy and clinical imaging modalities to bring high-resolution and detailed microvascular information into the clinic19. Several functional imaging methods have been developed to improve the microvascular imaging capabilities of clinical imaging modalities such as dynamic contrast-enhanced (DCE) MRI and CT20, and Intravoxel incoherent motion (IVIM) MRI21. However, these are model-based methods that provide indirect measurements of the microvasculature and thus, must be validated with appropriate &#34;ground truth&#34; measurements of the microvasculature19,22.
We have developed a dorsal skinfold window chamber (DSFC) tumor mouse model to bridge this gap between preclinical intravital microscopy and clinically applicable imaging modalities such as CT and MRI. The DSFC provides direct access to the tumor for high-resolution, intravital microscopy imaging through a glass window but also clinically applicable imaging such as MRI as it is made of MR-compatible materials (plastic and glass). Furthermore, an included MATLAB code performs multimodality 3D co-registration for direct spatial correlations between preclinical intravital microscopy and clinically applicable imaging modalities. Here we will describe the design and surgery to install the DSFC as well as the procedure to co-register intravital microscopy and clinically applicable imaging modalities.

作者聚焦：整合高分辨率活体成像和 MRI 以增强立体定向放射治疗计划

背侧皮褶窗室肿瘤小鼠模型在转化癌症研究中用于联合活体显微镜和磁共振成像

Preclinical intravital imaging has very high resolution, but limited depth penetration in the tissue, which makes it very good for preclinical imaging studies. On the other hand, MRI is much more clinically applicable and has a higher depth penetration, but very low spatial resolution. The goal of this study is to correlate these two modalities with each other in order to better translate our findings from preclinical intravital microscopy into the clinic via magnetic resonance imaging.Perfusion-sensitive imaging methods in MRI and biophotonics, including our optical coherence tomography and geography system, are revealing how the microvasculature impacts tumor response to hypofractionated radiotherapy. 3D printing is also aiding through cost-effective custom tool manufacturing, facilitating longitudinal studies. Finally, AI image analysis is facilitating the identification of novel radiotherapy predictive biomarkers.We've made several findings concerning the tumor response to hypofractionated radiotherapy, including more recently, the temporal kinetics of both radiobiologically significant and abstracted AI-derived tissue response metrics. Additionally, we have demonstrated the promise for multimodal imaging being performed more accurately, correlating both MRI, macroscopic and optical coherence tomography, microscopic, angiography-derived metrics. By extending the effective length of longitudinal studies, we may better identify predictive biomarkers for long-term tumor treatment response.Additionally, by improving robustness of co-registration between macroscopic clinically available imaging modalities and microscopic preclinical imaging modalities, we may enhance the translatability of our findings from benchtop to bedside. During a stereotactic body radiation therapy, high doses of radiation are delivering a reduced number of fractions. One potential radiobiological target associated with increased cell death in SVRT is the tumor microvasculature.By combining high-resolution optical angiography and MRI, we want to enable functional MRI microvascular imaging for patient-specific SVRT treatment planning and improved outcomes.

在肿瘤细胞注射小鼠中进行窗口室手术，用于肿瘤生长可视化和成像

首先，在高浓度液体消毒剂中对主窗室部件进行 12 分钟的消毒。然后浸泡在异丙醇中五分钟。在手术前一至三小时向肿瘤细胞注射的小鼠注射每公斤一毫克缓释丁丙诺啡。为了消毒，用7.5%聚维酮碘溶液擦洗麻醉和剃光的小鼠。用 70% 异丙醇清除消毒磨砂膏。将 10% 聚维酮碘溶液涂抹在皮肤上。最后，涂抹兽用眼部润滑剂以防止干燥。沿着脊柱提起小鼠的皮肤，并找到生长在其中一个侧向皮肤褶皱上的肿瘤。将背侧皮褶窗室（DSFC）的后框架置于框架内，使肿瘤位于框架内的中心。在 DSFC 和手术导板的顶部三个孔中添加三根缝合线，以固定后框架的位置。将三根针穿过 DSFC 的后框架插入包含垫片的孔中。使用手术记号笔，在皮肤上标记 DSFC 背框垫片的三个点。画一个直径为一厘米的圆圈，表示要去除的皮肤区域。在标记另外三个点后，剪开缝合线以去除针头和背架。使用手术微型剪刀从标记的圆圈中去除皮肤。然后放置临时缝合线，将窗室部件固定到皮肤上。用临时缝合线拧紧组件，然后通过孔将前框架插入皮肤下方。通过 DSFC 前后框架周边的孔放置永久性缝合线。取下临时缝合线后，将支撑夹固定在 DSFC 背架上。每公斤体重皮下注射5毫克美洛昔康给小鼠，以减轻疼痛和炎症。

window-chamber-surgery-tumor-cell-injected-mice-for-tumor-growth

Research

JoVE Journal

Cancer Research

Window Chamber Surgery in Tumor Cell Injected Mice for Tumor Growth Visualization and Imaging

A Dorsal Skinfold Window Chamber Tumor Mouse Model for Combined Intravital Microscopy and Magnetic Resonance Imaging in Translational Cancer Research

Preclinical intravital imaging such as microscopy and optical coherence tomography have proven to be valuable tools in cancer research for visualizing the ...

科研

癌症研究

Tumor Cells Inoculation in Mice Through Precise Landmarking and Injection Techniques

通过精确的定位和注射技术在小鼠中接种肿瘤细胞

Integrative Imaging Techniques for Tumor Analysis in Mice

用于小鼠肿瘤分析的综合成像技术