Establishing a mouse model of lung metastases using ultrasound-guided right heart ventricle injection

Abstract

We report a technique to generate a murine model of lung metastases by selectively injecting tumor cells into the right heart ventricle under ultrasound guidance. First, we describe cell preparation and reference animal preparation as previously described. We then detail the technique using a previously described 3D-printed instrument stabilization device. Finally, we describe tumor growth surveillance using bioluminescent imaging. For complete details on the use and execution of this protocol, please refer to Labora et al.¹.

Keywords: Cancer; Model Organisms.

Graphical abstract

Figure 1

Suggested extent of hair removal prior to ultrasound imaging

Figure 2

Appropriately mounted MicroScan Transducer (ultrasound probe) within the Vevo Imaging Station (A) MicroScan Transducer (ultrasound probe). (B) Transducer mounting system. (C) Animal physiological monitoring and maneuvering system.

Figure 3

Appropriately mounted and positioned needle stabilization device (A) Mounted ultrasound probe. (B) Needle stabilization device mounted in correct orientation on ultrasound probe. Note that ultrasound probe indicator snuggly fits into notch within needle stabilization device.

Figure 4

Mouse appropriately secured to imaging platform with paper tape

Figure 5

Suggested positioning of the platform for cardiac imaging

Figure 6

Short axis cardiac window with labeled anatomic landmarks

Figure 7

Image of loaded syringe stabilization device

Figure 8

Ultrasound image of needle positioned within the right ventricle

Figure 9

Representative BLI imaging of C57BL/6 mice injected with 1 × 10⁶ B16F10-luc cells from 2 to 12 days post-injection Bars denote 1 cm.

Figure 10

Representative BLI imaging of C57BL/6 mice injected with 1 × 10⁶ B16F10-luc cells per mouse at experimental endpoint (12 days post-injection) alongside harvested lungs demonstrating pigmented metastatic lesions Bars denote 1 cm.

Figure 11

Representative BLI imaging of C57BL/6 mice injected with 1 × 10⁶ CGF3R-L3-luc cells per mouse from 3 to 14 days post-injection alongside harvested lungs demonstrating cystic metastatic lesions at experimental endpoint (day 14) Bars denote 1 cm. White outline highlights examples of cystic metastatic lesions within lung tissue.

Figure 12

Representative BLI imaging of C57BL/6 mice injected with 1 × 10⁶ CGF3R-L3-luc cells per mouse at experimental endpoint (14 days post-injection) alongside harvested lungs demonstrating cystic metastatic lesions Bars denote 1 cm. White outline highlights examples of cystic metastatic lesions within lung tissue.

Figure 13

Example of boot shaped BLI signal resulting from intracardiac injection along with necropsy photo This mouse was injected with 1 × 10⁶ B16F10-luc cells per mouse. Arrows showing mediastinal tumor burden. Bar denotes 1 cm.

Figure 14

Representative BLI imaging of C57BL/6 mice injected with 1 × 10⁶ B16F10-luc cells from 2 to 12 days post injection Mice were injected using either the standard tail vein technique (left) or ultrasound-guided right ventricle (US-RV) technique (right). Bars denote 1 cm.

Figure 15

Example of possible positioning strategies to obtain an ideal injection window

Figure 16

Representative image demonstrating the different patterns of metastatic engraftment seen with left ventricular vs. right ventricular injection C57BL/6 mice were injected with 1 × 10⁶ B16F10-luc cells per mouse. BLI imaging was performed at 8 days post-injection. Bars denote 1 cm.