Induction of Right Ventricular Failure by Pulmonary Artery Constriction and Evaluation of Right Ventricular Function in Mice

Summary

Here, we provide a useful approach for studying the mechanism of right ventricular failure. A more convenient and efficient approach to pulmonary artery constriction is established using surgical instruments made inhouse. In addition, methods to evaluate the quality of this approach by echocardiography and catheterization are provided.

Abstract

The mechanism of right ventricular failure (RVF) requires clarification due to the uniqueness, high morbidity, high mortality, and refractory nature of RVF. Previous rat models imitating RVF progression have been described. Compared with rats, mice are more accessible, economical, and widely used in animal experiments. We developed a pulmonary artery constriction (PAC) approach which is comprised of banding the pulmonary trunk in mice to induce right ventricular (RV) hypertrophy. A special surgical latch needle was designed that allows for easier separation of the aorta and the pulmonary trunk. In our experiments, the use of this fabricated latch needle reduced the risk of arteriorrhexis and improved the surgical success rate to 90%. We used different padding needle diameters to precisely create quantitative constriction, which can induce different degrees of RV hypertrophy. We quantified the degree of constriction by evaluating the blood flow velocity of the PA, which was measured by noninvasive transthoracic echocardiography. RV function was precisely evaluated by right heart catheterization at 8 weeks after surgery. The surgical instruments made inhouse were composed of common materials using a simple process that is easy to master. Therefore, the PAC approach described here is easy to imitate using instruments made in the lab and can be widely used in other labs. This study presents a modified PAC approach that has a higher success rate than other models and an 8-week postsurgery survival rate of 97.8%. This PAC approach provides a useful technique for studying the mechanism of RVF and will enable an increased understanding of RVF.

Introduction

RV dysfunction (RVD), defined here as evidence of an abnormal RV structure or function, is associated with poor clinical outcomes. RVF, as the end stage of RV function, is a clinical syndrome with signs and symptoms of heart failure that result from progressive RVD¹. With differences in structure and physiological function, left ventricular (LV) failure and RVF have different pathophysiological mechanisms. A few independent pathophysiological mechanisms in RVF have been reported, including overexpression of β2-adrenergic receptor signaling², inflammation³, transverse tubule remodeling, and Ca....

Access restricted. Please log in or start a trial to view this content.

Protocol

All procedures were performed in accordance with institutional guidelines for animal research, which conform to the Guide for the Care and Use of Laboratory Animals published by the US National Institutes of Health (NIH Publication No. 85-23, revised in 1996). C57BL/6 male mice (8-10 weeks old, weighing 20-25 g) were provided by the Animal Center of South Medical University. After arrival, the mice were housed under a 12/12 h dark/light cycle, with sufficient food and water.

1. Preparation of the surgical instruments and fabrication of the needles

1. Prepare the sterile surgical instruments (Figure 1A)....

Access restricted. Please log in or start a trial to view this content.

Results

In this study, mice were randomly assigned to the PAC group (n = 9) or the sham operation group (n = 10). Echocardiography was performed at 1, 4, and 8 weeks after the surgery. Eight weeks after surgery, following the last echocardiography and catheterization assessments, the mice were euthanized, and their hearts were harvested for a morphological and histological assessment.

Pulmonary trunk constriction cause.......

Access restricted. Please log in or start a trial to view this content.

Discussion

Pathological increases in RV filling pressures result in a leftward shift of the septum, which can alter the LV geometry²¹. These changes contribute to reduced cardiac output and LV ejection fraction (LVEF), which can cause a hemodynamic disorder of the circulatory system²². Therefore, an efficient, stable, and economical model for studying the mechanism of RVF is valuable.

We developed a more effective and highly reproducible approach to PAC usi.......

Access restricted. Please log in or start a trial to view this content.

Materials

Name	Company	Catalog Number	Comments
ALC-V8S ventilator	SHANGHAI  ALCOTT  BIOTECH  CO	ALC-V8S	Assist ventilation
Animal Mini Ventilator	Haverd	Type 845	Assist ventilation
Animal ultrasound system VEVO2100	Visual Sonic	VEVO2100	Echocardiography
Cold light illuminator	Olympus	ILD-2	Light
Heat pad- thermostatic surgical system (ALC-HTP-S1)	SHANGHAI  ALCOTT  BIOTECH  CO	ALC-HTP-S1	Heating
Isoflurane	RWD life science	R510-22	Inhalant anaesthesia
Matrx VIP 3000 Isofurane Vaporizer	Midmark Corporation	VIP 3000	Anesthetization
Medical braided silk suture (6-0)	Shanghai Pudong Jinhuan Medical Supplies Co.	6-0	Ligation
Medical nylon suture (5-0)	Ningbo Medical Needle Co.	5-0	Suture
Millar Catheter (1.0 F)	AD instruments	1.0F	For right heart catheterization
Pentobarbital sodium salt	Merck	25MG	Anesthetization
PowerLab multi-Directional physiological Recording System	AD instruments	4/35	Record the result of right heart catheterization
Precision electronic balance	Denver Instrument	TB-114	Weighing sensor
Self-made latch needle			Separate the aorta and pulmonary trunk
Self-made padding needle			Constriction
Self-made tracheal intubation			Tracheal intubation
Small animal microsurgery equipment	Napox	MA-65	Surgical instruments
Transmission Gel	Guang Gong pai	250ML	Echocardiography
Veet hair removal cream	Reckitt Benchiser	RQ/B 33 Type 2	Remove hair of mice
Vertical automatic electrothermal pressure steam sterilizer	Hefei Huatai Medical Equipment Co.	LX-B50L	Auto clean the surgical instruments
Vertical small animal surgery microscope	Yihua Optical Instrument	Y-HX-4A	For right heart catheterization