Full-thickness splinted skin wound healing models in db/db and heterozygous mice: Implications for wound healing impairment
s The excisional dorsal full‐thickness skin wound model with or without splinting is widely utilized in wound healing studies using diabetic or normal mice. However, the effects of splinting on dermal wound healing have not been fully characterized, and there are limited data on the direct compariso...
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| Published in | Wound repair and regeneration Vol. 22; no. 3; pp. 368 - 380 |
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| Main Authors | , , , , , , , , , |
| Format | Journal Article |
| Language | English |
| Published |
United States
Blackwell Publishing Ltd
01.05.2014
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| Subjects | |
| Online Access | Get full text |
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| Summary: | s
The excisional dorsal full‐thickness skin wound model with or without splinting is widely utilized in wound healing studies using diabetic or normal mice. However, the effects of splinting on dermal wound healing have not been fully characterized, and there are limited data on the direct comparison of wound parameters in the splinted model between diabetic and normal mice. We compared full‐thickness excisional dermal wound healing in db/db and heterozygous mice by investigating the effects of splinting, semi‐occlusive dressing, and poly(ethylene glycol) treatment. Two 8‐mm full‐thickness wounds were made with or without splinting in db/db and heterozygous mice. Body weights, splint maintenance, wound contraction, wound closure, and histopathological parameters including reepithelialization, wound bed collagen deposition, and inflammation were compared between groups. Our results show that silicone splint application effectively reduced wound contraction in heterozygous and db/db mice. Splinted wounds, as opposed to nonsplinted wounds, exhibited no significant differences in wound closure between heterozygous and db/db mice. Finally, polyethylene glycol and the noncontact dressing had no significant effect on wound healing in heterozygous or db/db mice. We believe these findings will help investigators in selection of the appropriate wound model and data interpretation with fully defined parameters. |
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| Bibliography: | National Institute of Health - No. RC2AR058971 Figure S1. Schematics of splinted-covered (A), nonsplinted-covered (B), and nonsplinted-uncovered (C) wounds in mice and photographs of a splinted-covered wound (D) and a nonsplinted-uncovered wound (E) in diabetic mice on day 6. We attempted to make the location of wounds (red circles) identical in all mice. In the splinted groups, silicone splints (orange donuts in A) were affixed with adhesive and eight interrupted sutures (black lines in A). In the nonsplinted-covered groups, silicone o-rings (orange donuts in B) were fixed with an interrupted suture (a black line in B). In covered groups, a trimmed plastic cover slip was placed on top of the splint/o-ring (blue squares in A, B), and a semi-occlusive dressing was applied circumferentially around the trunk of the animal (pale blue part in A, B). Area wound closure was calculated as original wound area on day 0-area open wound on day "X" (area inside inner red circumferential circle in D). Area wound contraction was calculated as original wound area on day 0-area including open wound and new epithelium on day "X" (area inside area inside outer blue circumferential circle in D). Uncovered wounds could not be traced because the wound edges and new epithelium were covered by eschars (E). Figure S2. Measurement of the epithelial gap (blue line in A), reepithelialization (red lines in A), and fibrovascular dermal proliferation for a nonsplinted-covered wound bed of a db/db mouse (B and C) treated with PEG for 10 days and harvested 11 days after wounding. (A) The epithelial gap was defined as the distance between the advancing edges of keratinocyte migration measured in millimeters. Length of reepithelialization was defined as the length of the layer of proliferating and migrating keratinocytes covering the wound area. This value was obtained by measuring the distance between the free edge of the keratinocyte layer and the base where the cells were still associated with native, nonaffected dermal tissue. The final value was the sum of distance in millimeters of both sides. Bar = 500 μm. (B) The wound bed area was outlined (red lines), and it comprises a preset depth of 0.75 mm (this is the average experimental wound depth) and the borders between preexisting dermal collagen (*) and newly formed collagen. (C) Under polarized light, the bright collagen fibers of the wound bed are automatically measured by the software, and the final data are expressed as a percentage of the outlined wound area. Diabetic mouse skin, Picrosirius red stain. Bar = 500 μm. Figure S3. Quantification of types of collagen deposited in the wound bed of db/db mice and heterozygous mice. Low magnification image of the wound of a splinted wound in a db/db mice (A) and a splinted wound in a heterozygous mice (C). (B and D) Higher magnification of the doted squares on A and C, respectively. Note the predominance of red-yellow-orange (type I collagen) fibers on A and B and increased deposition of green (type III collagen) fibers on C and D. Borders of the wound bed (arrows). Picrosirius-red stain under polarized light. A and C, Bars = 1 mm. B and D, Bars = 200 μm. Figure S4. Kaplan-Meier survival curves for splint maintenance. Data were compared between heterozygous and db/db mice with experimental conditions of (A) splinted-covered with PEG treatment, (B) splinted-covered without treatment. No statistical significance was observed between heterozygous and db/db mice (p = 0.54 between PEG-treated groups: A; p = 0.18 between untreated groups: B). When the splint status met our criteria of "splint success" until euthanasia on day 11, 11 was entered as the day of splint failure, and the data were processed as "censored." Figure S5. Relative fluorescence expression of MMP 2 and 9 in three representative samples selected based on epithelial gap and collagen content. Immunohistochemical analyses were performed on wound bed samples from day 11. Data are comparisons between heterozygous and db/db mice across (A) splinted-covered, (B) nonsplinted-covered, (C) nonsplinted-uncovered groups. No significant differences were observed. ArticleID:WRR12172 istex:C27DA019DB9AEF35FB5C7DDF368628F0D4337E92 ark:/67375/WNG-4N8RPZ7Q-D ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 1067-1927 1524-475X |
| DOI: | 10.1111/wrr.12172 |