Development of an Efficient Murine Tissue Expansion Model for Skin Regeneration Research

Summary

This research presents a practical and efficient protocol for establishing a continuous tissue expansion model in rats, thereby facilitating the mechanism investigation and technique advancement in skin regeneration.

Abstract

Skin regeneration is essential for the healing of various superficial wounds and can be promoted by mechanical stimulation. Tissue expansion is a widely used strategy to accelerate skin regeneration by controlled mechanical stretch; however, its clinical efficacy is often restricted by a mismatch between mechanical loading and the skin's regenerative capacity. To address this limitation, the development of a standardized animal model of tissue expansion is urgently required. In this study, we established a tissue expansion model in Sprague-Dawley rats. Following the dorsal implantation of a 10 mL tissue expander, 5 mL of saline was injected immediately after the surgery. After a two-week recovery period, animals underwent a regimen of twice-weekly saline injections (10 mL per session). The expansion kinetics exhibited a characteristic trend of rapid skin growth followed by a gradual deceleration. In the later stages, severe complications such as skin necrosis, tissue breakdown, and expander exposure were observed. This work establishes a reproducible preclinical framework that closely mimics the physiological and pathological processes of human tissue expansion, providing a foundational model to investigate regenerative mechanisms and optimize clinical protocols.

Introduction

Skin serves as the body's first line of defense, providing mechanical protection and preventing water loss, while also playing crucial roles in temperature regulation, external stimuli response, and immune regulation¹. Skin wounds are common in clinical practice, resulting from trauma, microbial infections, chemical damage, and surgical resection². While small wounds could heal with a normal appearance, large injuries generally leave behind a severe fibrotic scarring that impairs tissue function and may even become life-threatening³. Autologous full-thickness skin grafting is widely considered the....

Protocol

All animal procedures were approved by the Ethics Committee of Shanghai Ninth People's Hospital (No. SH9H-2025-A1673-1) and conducted in accordance with the National Institutes of Health Guide for the Care and Use of Laboratory Animals.

1. Preparation

1. Acclimatize all SD rats for 7 days prior to the study. House SD rats in an animal facility with a 12 h light/12 h dark cycle. Provide a standard wheat/soy-based diet and water ad libitum throughout the experiment.
2. Design 10 mL semicircle tissue expanders for experimental use (Figure 1A), which comprise an expansi....

Results

In this study, we established a standard protocol for a continuous tissue expansion model. After confirming the safety of the expander (Figure 1A), it was surgically implanted subcutaneously into the dorsal region of SD rats. Its inflating surface was positioned toward the skin. To prevent expander displacement, the connection point between the catheter and injection port was secured to the muscular fascia (Figure 1B). Following the twice-weekly saline injection.......

Discussion

Tissue expansion has emerged as a widely used technique to generate additional skin that closely resembles the neighboring healthy skin in terms of texture and color¹⁹. It has been applied in diverse clinical conditions, including scars repair, breast reconstruction, and reconstruction following the resection of body surface tumors²⁰. However, the long-term tissue expansion still remains a critical challenge, primarily due to exhausted skin regenerative capacity

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
CD31 antibody	Abcam Shanghai Trading Co.,Ltd	ab182981	IHC staining
Electron-beam irradiation instrument	Tongwei Xinda Technology (Jiangsu) Co,. Ltd	High-energy electron accelerator (10 MeV, 24 kW)	Sterilization
FITC-conjugated secondary antibody	Proteintech Group, Inc	SA0003-2	IHC staining
Graghpad Prism software	GraphPad Software	Version 10.0	Statistical analysis
Hematoxylin and Eosin Staining Kit	Beyotime Biotech Inc	C0105S	Histological staining
High-Precision 3D Scanner	SHINING 3D	EinScan Pro 2X V2	Area measurement
Image J software	National Institutes of Health	Version 1.54	Statistical analysis
Masson's Trichrome Staining Kit	Beyotime Biotech Inc	C0189S	Histological staining
Tissue expanders	Shanghai Winner Plastic surgery Products Co.,Ltd.	N/A	Special customization