Digital Planimetry for Assessing Wound Closure Kinetics in a Mouse Model

Summary

Wounds represent a global health challenge. This study developed a standardized photo booth utilizing digital planimetry to minimize wound measurement variability. Monitoring wounds in mice over 14 days revealed an initial increase in wound area and perimeter, followed by gradual closure. This methodology may aid in evaluating wound closure kinetics in pre-clinical models.

Abstract

Chronic wounds, due to their high prevalence, are a serious global health concern. Effective therapeutic strategies can significantly accelerate healing, thereby reducing the risk of complications and alleviating the economic burden on healthcare systems. Although numerous experimental studies have investigated wound healing, most rely on qualitative observations or quantitative direct measurements. The objective of this study was to standardize an indirect wound measurement method using digital planimetry, incorporating digital scaling and segmentation. This approach addresses the lack of detailed, step-by-step methodologies for accurate wound assessment. A photodocumentation booth was designed and constructed, and computer-assisted digital planimetry tools were employed to minimize variability in measurements of the wound area, perimeter, and the distance from the wound center to its edges. A circular traumatic wound (5 mm in diameter) was created on the dorsal midline at the shoulder blade level of male CD1 mice (n = 4, 10 weeks old, 30-35 g). Wound evolution was photodocumented for 14 days using the custom-designed photo booth, which controlled lighting conditions, focal distance, and subject positioning. Scaling and wound measurements were performed using segmentation in ImageJ software, and statistical analysis was conducted using statistical analysis software. The kinetics of wound closure showed a slight increase in wound size and perimeter between day 0 and day 2, followed by a gradual decrease until complete closure by day 14. The photodocumentation booth and computer-assisted digital planimetry enabled quantitative measurements with minimal variability. In conclusion, these tools provide a reliable and reproducible method for evaluating wound closure kinetics in pre-clinical models.

Introduction

Traumatic wound healing takes approximately 21 days and has a well-defined sequence of four distinct phases: (1) hemostasis, (2) inflammation, (3) proliferation, and (4) remodelling¹. If any phase of wound healing is prolonged, it can lead to the development of chronic wounds¹. Due to their high prevalence, potential complications², and significant economic burden, they are considered a global health problem.

Pre-clinical studies aim to achieve faster healing by promoting comprehensive wound re-epithelialization^3,4

Protocol

All experimental procedures involving laboratory mice were conducted in accordance with the ethical standards and regulations established in the Official Mexican Standard (NOM-062-ZOO-1999) for the handling and care of laboratory animals. The protocol was reviewed and approved by the Internal Committee for the Care and Use of Laboratory Animals (CICUAL) of the National Institute for Nuclear Research (ININ) under reference number CICUAL-01-23. Male CD1 mice (n = 4), 10 weeks old, with a body weight ranging from 28-32 g, w.......

Discussion

In pre-clinical models, quantitatively analyzing the evolution of traumatic wounds in pre-clinical models faces challenges due to factors like wound size, localized inflammatory response³⁴, location, and/or manipulation. Direct manual³⁶ and indirect digital^11,16,37,38 planimetry methods exist for these measurements. In contrast to studies using ma.......

Materials

Name	Company	Catalog Number	Comments
5 mm Biopsy Punch	MILTEX, USA	33-35	To mark the wound edges
Aluminum with polyethylene core	Alucobond,USA	Bright Silver 119	For the construction of the macroscopic Image Acquisition Booth
Camera Lens	Sony, Japan	SEL2470Z	To focus the images to photograph
Electrocautery	Bonart, USA	ART-E1	To eliminates bleeding points in the wound if present.
Hook and loop fastener strips	VELCRO
IBM SPSS Statistics Version 22	IBM Corporation, USA	https://www.ibm.com/analytics/spss-statistics	Used for statistical analysis of wound measurements, including area and perimeter data.
ImageJ Version 1.53t	National Institutes of Health, USA	https://imagej.nih.gov/ij/	Used for processing macroscopic images, including scaling, segmentation, and measurement of wound parameters.
Ketorolac	SIEGFRIED RHEIN, Mexico	493977	For postoperative pain management
Miltex Iris Scissors, 4-1/8" Curved	MILTEX, USA	V95-306	To cut the wound flap generated with the biopsy punch
RGB LED Light Tube	ANDOER, China	‎ B09F8RLMSY	To illuminate the Macroscopic Image Acquisition Booth
Semi profesional camera	Sony, Japan	DSC-HX300	To take the photos
Serrated Forceps	MILTEX, USA	V96-118	To hold the flap during the cut
Sevoflurane	Baxter, USA	AMX2L9117PR	For inhaled anaesthesia
Sodium Pentobarbital	Aranda, Mexico	734.448.001.212	For intraperitoneal anaesthesia
SolidWorks Version 2015	Dassault Systèmes, France	https://www.solidworks.com/	Used to design and create 3D models for constructing  accessories for the photodocumentation booth.
Surgical blades	HERGOM, Mexico	H10	To shave the hair in the area where the wound will be created
Transparent Adhesive Dressing	3M, USA	F51CA07	To cover the traumatic wound