Murine Model of Thoracic Aortic Dissection Induced by Oral β-Aminopropionitrile and Subcutaneous Angiotensin II Infusion

Summary

This protocol provides a detailed, step-by-step procedure for the induction of thoracic aortic dissection in mice. Specifically, it includes the precise calculation of the required doses of β-aminopropionitrile and angiotensin II, the procedure for osmotic pump filling, and the implantation technique of the osmotic pump.

Abstract

Thoracic aortic dissection (TAD) is a highly fatal cardiovascular disease that lacks efficient medical treatment. Replication of animal models of TAD pathophysiology is essential for studying the intrinsic mechanisms of TAD. The widely used TAD model induced by β-aminopropionitrile (BAPN, an irreversible and orally active lysyl oxidase inhibitor) in mice has the limitation of an inconsistent success rate. This protocol describes in detail a reported modified murine model of TAD induced by oral BAPN combined with subcutaneous angiotensin II (Ang II) infusion. After four weeks of BAPN administration followed by 24 h of Ang II infusion, a murine model with characteristics similar to human TAD was reliably induced, and the success rate of TAD model construction was significantly improved. Oral BAPN inhibits the cross-linking of elastin and collagen, resulting in the destruction of the aortic wall structure and inducing aortic dilation and dissection formation to a certain extent. The subsequent induction of Ang II further exacerbates the degeneration of the aortic wall, thereby promoting the occurrence of TAD. Consequently, the combination of BAPN and Ang II represents a refined approach to constructing a murine TAD model, offering a valuable tool to explore the pathogenesis and potential therapeutic approaches for TAD.

Introduction

Thoracic aortic dissection (TAD) is a serious aortic disease caused by an intimal tear due to bleeding within the wall of the thoracic aorta, resulting in separation of the aortic wall layers, blood entering the media of the aortic wall, forming a false lumen, and causing pressure on the true lumen^1,2,3. Epidemiologic studies suggest that the incidence of TAD is between 7 and 9 cases per 100,000 people per year⁴. At present, it is believed that the pathogenesis of TAD is caused by the abnormal structure and hemodynamics of the aortic media, and factors....

Protocol

Animal protocols were approved by the Institutional Animal Care and Use Committee of Tianjin Medical University (Approval Number TMUaMEC 2022036). Three-week-old C57BL/6J male mice were used in this study. Details of the reagents and equipment used are listed in the Table of Materials.

1. Animal maintenance and grouping

1. Raise the mice on standard maintenance chow. Use three-week-old mice for this study.
2. Randomly assign the mice to the control group (Control), the oral BAPN group (BAPN), the oral BAPN and saline infusion group (BAPN + Saline), and the oral BAPN and Ang II infusion group (BAPN + Ang II) ....

Results

A total of 70 male C57BL/6J mice, aged 3 weeks, were included in this study and randomly assigned to four groups: Control (n = 10), BAPN (n = 20), BAPN + Saline (n = 20), and BAPN + Ang II (n = 20). In the BAPN group, 11 out of 20 mice developed thoracic aortic dissection (TAD) 28 days after BAPN administration, with 4 mice dying from aortic rupture. In the BAPN + Saline group, 12 out of 20 mice developed TAD, with 4 deaths due to rupture. Notably, in the BAPN + Ang II group, all 20 mice .......

Discussion

Due to the limited understanding of life-threatening thoracic aortic dissection (TAD), the establishment of stable animal models is essential for exploring the molecular mechanisms underlying TAD onset and progression. β-Aminopropionitrile (BAPN), a lysyl oxidase inhibitor, is widely used in rodent models of TAD because it disrupts the cross-linking of collagen and elastin, thereby weakening the aortic wall and increasing its susceptibility to mechanical stress¹³. However, BAPN administration.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
3-Aminopropionitrile Fumarate salt	Sigma-Aldrich	A3134
Analytical balance	Radwag	AS 220.R2
Anesthesia Machine	Shanghai Renyi Biological Technology Co. Ltd.	MSS-3
Angiotensin II	MCE	HY-13948
C57BL/6J Male Mice	GemPharmatech	N000013
Chow Diet	Sibeifu Beijing Biotechnology Co. Ltd	SPF-F02-002
Electrothermal constant temperature water tank	Yiheng Technical Co. Ltd.	DK-8D
EVG Staining Kit	Solarbio	G1590
GraphPad Prism	Graphpad	Ver 10.0.2
H&E Staining Kit	Servicebio	G1076
Hemostat	Shinva Medical Instrument Co. Ltd.	ZH240RN
Isoflurane	RWD	R510-22-10
Microtube	Axygen Scientific, Inc.	MCT-150-C
Needle forcep	Shinva Medical Instrument Co. Ltd.	ZM234R/RN/RB
Osmotic pump	Alzet	1003D
Paraformaldehyde	Servicebio	G1101
PBS, 1x	Servicebio	G4202
Saline	Servicebio	G4702
Scalpel	Shinva Medical Instrument Co. Ltd.	ZB084R/RN
Scissor	Shinva Medical Instrument Co. Ltd.	ZC480RN/RB/RNj/RNh
Stereo microscope	Leica	EZ4
Suture	Jinhuan Medical Supplies Co. Ltd.	F604
Tweezer	Shinva Medical Instrument Co. Ltd.	ZO022RB