Histology Scoring System for Murine Cutaneous Wounds

Abstract

Monitoring wound progression over time is a critical aspect for studies focused on in-depth molecular analysis or on evaluating the efficacy of potential novel therapies. Histopathological analysis of wound biopsies can provide significant insight into healing dynamics, yet there is no standardized and reproducible scoring system currently available. The purpose of this study was to develop and statistically validate a scoring system based on parameters in each phase of healing that can be easily and accurately assessed using either Hematoxylin & Eosin (H&E) or Masson's Trichrome (MT) staining. These parameters included re-epithelization, epithelial thickness index, keratinization, granulation tissue thickness, remodeling, and the scar elevation index. The initial phase of the study was to (1) optimize and clarify healing parameters to limit investigator bias and variability; (2) compare the consistency of parameters assessed using H&E versus MT staining. During the validation phase of this study, the accuracy and reproducibility of this scoring system was independently iterated upon and validated in four different types of murine skin wound models (Excisional; punch biopsy; pressure ulcers; burn wounds). A total of n = 54 histology sections were randomized, blinded, and assigned to two groups of independent investigators (n = 5 per group) for analysis. The sensitivity of each parameter (ranging between 80% and 95%) is reported with illustrations on the appropriate assessment method using ImageJ software. In the validated scoring system, the lowest score (score:0) is associated with an open/unhealed wound as is evident immediately and within the first day postinjury, whereas the highest score (score:12) is associated with a completely closed and healed wound without excessive scarring. This study defines and describes the minimum recommended criteria for assessing wound healing dynamics using the SPOT skin wound score. The acronym SPOT refers to the academic and scientific institutions that were involved in the development of the scoring system, namely

Topical Administration of a Marine Oil Rich in Pro-Resolving Lipid Mediators Accelerates Wound Healing in Diabetic db/db Mice through Angiogenesis and Macrophage Polarization

“…Parameters measured included the epithelial thickness, granulation tissue, maturation of collagenous tissue, and scar elevation index ( Table 2 ). A histology score to determine wound healing status was calculated as described in [ 44 ], which is based on different criteria using both quantitative and semi-quantitative measures, such as re-epithelization, angiogenesis, epithelial thickness, keratinization, granulation tissue formation, scar elevation index, and remodeling. We obtained a score of 5.8 ± 1.07 in control animals and 8.4 ± 0.92 in LIPINOVA ® -treated animals (* p < 0.05) ( Figure 4 D).…”

“…Because angiogenesis is detected in the last phases of the wound healing process [ 44 ], we measured vessel density at the wound sites by immunofluorescence, using an antibody to caveolin. Results showed that the number of vessels was significantly higher in the animals treated with LIPINOVA ® than in the saline-treated mice ( Figure 5 D,E), which fitted well with the results of the histology score (that included this parameter).…”

“…Inflammatory infiltrates of H&E-stained sections from the different treated groups and a histology score of wound healing was assessed by researchers blinded to the group categorization of the animals, as described in [ 44 ]. The scar elevation index was calculated measuring the dermal thickness at the site of the wound (DTW) or in healthy non-wounded (DTH) areas, as follows: (DTH-DTW)/DTW.…”

Himatanthus bracteatus-Composed In Situ Polymerizable Hydrogel for Wound Healing

“…Histopathological analysis of wound biopsies can bring interesting insights into healing dynamics [ 39 ], but to provide significant information on the healing progress it must properly include the basic components of the healing process, such as angiogenesis, inflammation, fibroplasia and connective tissue matrix restoration, wound contraction and remodeling, and epithelialization [ 40 ]. The scoring system used in the current work was designed in such a way that lower scores are associated with unhealed wounds, whereas higher scores are associated with completely closed and healed wounds without excessive scarring.…”

Antibacterial Activity of Syzygium aromaticum (Clove) Bud Oil and Its Interaction with Imipenem in Controlling Wound Infections in Rats Caused by Methicillin-Resistant Staphylococcus aureus

“…Inflammation is an early reaction to an injury, and it is mediated through various inflammatory cells that include macrophages, neutrophils, and plasma cells. However, the presence of inflammatory cells in the wounded tissue several days after wounding shows incomplete wound healing [ 54 ]. An increase in epidermal height and capillary number and a decrease in inflammatory cells after the clove oil treatment showed increased healing of wounds.The fast and rapid wound healing activity of clove oil may be due to the antioxidant and anti-inflammatory activities of its phytochemical contents in addition to its antibacterial effect, especially with respect to phenolic compounds [ 55 , 56 ].…”