An Apical Resection Model in the Adult Xenopus tropicalis Heart

Summary

Xenopus tropicalis is an ideal model for regenerative research as many of its organs possess a remarkable regenerative capacity. Here, we present a method for constructing a heart injury model in X. tropicalis via apex resection.

Abstract

It is known that in adult mammals, the heart has lost its regenerative capacity, making heart failure one of the leading causes of death worldwide. Previous research has demonstrated the regenerative ability of the heart of the adult Xenopus tropicalis, an anuran amphibian with a diploid genome and a close evolutionary relationship with mammals. Additionally, studies have shown that following ventricular apex resection, the heart can regenerate without scarring in X. tropicalis. Consequently, these previous results suggest that X. tropicalis is an appropriate alternative vertebrate model for the study of adult heart regeneration. A surgical model of cardiac regeneration in the adult X. tropicalis is presented herein. Briefly, the frogs were anesthetized and fixed; then, a small incision was made with iridectomy scissors, penetrating the skin and pericardium. Gentle pressure was applied to the ventricle, and the apex of the ventricle was then cut out with scissors. Cardiac injury and regeneration were confirmed by histology at 7-30 days post resection (dpr). This protocol established an apical resection model in adult X. tropicalis, which can be employed to elucidate the mechanisms of adult heart regeneration.

Introduction

Heart failure has been a leading cause of mortality worldwide in recent years. Since 2000, the number of deaths due to heart failure has been increasing over time. More than 9 million people died from cardiomyopathy in 2019, which accounted for 16% of the total number of mortalities globally¹. Due to the loss of the regenerative capacity of the heart in adult mammals, in some cases, there are not enough cardiomyocytes to maintain the contraction functions in the heart, which affects heart function and contributes to abnormal ventricular remodeling and heart failure^2,3

Protocol

All the experimental protocols related to X. tropicalis were approved by the Jinan University Animal Care Committee.

1. Surgery

1. Preoperative preparation: Keep ready ophthalmic scissors, ophthalmic forceps, needle forceps, absorbent balls, filter paper, and surgical sutures/needles for apex resection in the hearts of X. tropicalis. Refer to the Table of Materials for detailed information. Before use, sterilize all the surg.......

Discussion

Apical resection, which involves the surgical amputation of the apex of the heart, has been described in zebrafish and mice^6,18; however, this has not been described in X. tropicalis. This report describes a credible model of cardiac injury and demonstrates that the heart of adult X. tropicalis can fully regenerate after apical resection without scarring. However, some shortcomings need to be improved, and certain details need attention.

Materials

Name	Company	Catalog Number	Comments
Acetic acid	GHTECH	64-19-7-500ml
Acid Alcohol Fast Differentiation Solution	Beyotime	C0163M
Acid Fuchsin	aladdin	A104916
Alcohol Soluble Eosin Y Stainin Solution	Servicebio	G1001-500ML
BioReagent	Beyotime	ST2600-100g
Ethanol absolute	Guangzhou Chemical Reagent Factory	HB15-GR-0.5L
Hematoxylin Stain Solution	Servicebio	G1004-500ML
Neutral balsam	Solarbio	G8590
Operating Scissors	Prosperich	HC-JZ-YK-Z-10cm
Paraffins	Leica	39601095
Para-formaldehyde Fixative	Servicebio	G1101-500ML
Phosphate Buffered Saline (PBS) powder	Servicebio	G0002-2L
Phosphomolybdic acid hydrate	Macklin	P815551
Stereo microscope	Leica
surgical forceps	ChangZhou	zfq-11-btjw
Surgical Suture	HUAYON	18-5140
Tricaine	Macklin
Xylene	Guangzhou Chemical Reagent Factory	IC02-AR-0.5L