engleski

Excisional wound healing in db/db mice

Introduction: Animal models for impair wound healing are helpful in preclinical testing to assess activity of potent new wound healing agents. Genetically diabetic mice (db/db mice) are most used animal model for impaired-healing, since wound healing in these animals is markedly delayed when compared with non-diabetic littermates. Healing impairment is characterized by delayed cellular infiltration and granulation tissue formation, reduced angiogenesis, decreased collagen and its organization. Full thickness excisional wounds are model for evaluation of contraction and re-epithelialisation of the wounds. In contrast to normal mice, contraction is a minor mechanism of wound healing in db/db mice. Instead, epithelialization plays a major role in wound closure. In present study we demonstrated an objective, precise and reproducible means for monitoring skin wound closure and the effects of therapeutic measures by simply adapting existing computerized technologies. Materials and Methods: Female db/db mice (C57Bl/Ks inbred strain of mice with a single gene mutation inherited as an autosomal allele on chromosome 4, linkage group VIII, with complete penetrance) and female C57Bl/6 mice were obtained from &laquo ; ; ; ; Charles River&raquo ; ; ; ; , Belgium. Experimental animals were treated in accordance with the criteria outlined in the PHS Policy on Human Care and Use of Laboratory Animals and the Guide for the care and Use of Laboratory Animals. Using a modification of the technique, described by Denon et al. The wounds were treated topically with Regranex (Jansen-Cilag) or carbopool gel and compared with non-treated wounds. During the 18 days healing period, wound closure was documented with a digital camera (Olympus C-2040 Zoom, Olympus Optical Co., Ltd, Japan) on day 0, 1, 3, 6, 9, 13 and 18. Images were analyzed using LEICA QWin Image Processing and Analysis System (Leica Imaging System Ltd, UK) software by tracing the wound margin with a fine resolution computer mouse and calculating pixel area. Measurements were performed in duplicate and mean values of consecutive tracing were computed and expressed as percentage of closure from original wound or of wound measured on day 3. Analyses of variance (proc ANOVA in SAS/Stat) and Dunnet test were performed. Level of significance was α = 0, 05. Graphical presentation of data was done in form of Box-Whisker plots. Results: The rate of wound retraction was more pronounced in treated animals, especially in diabetic mice treated with Regranex. There was a marked difference in wound sizes between the animals within the same group, particularly in C57Bl/6 mice. It has been noticed that non-diabetic animals are much more agitated in comparison with diabetic animals, and, therefore, more often cause an extra trauma of the wound tissue by scraping the wound. Nevertheless, in C57Bl/6 mice, most of the wounds were closed within 13 days, and in db/db mice within 18 days. Diabetic animals treated with carbopol gel had the same decrease of wound areas as non-treated diabetic mice throughout the whole experiment. Diabetic animals treated with Regranex had reduced rate of decrease of wound area in comparison with non-treated diabetic mice throughout the whole experiment, and especially on day 13. Conclusion: Wounds in db/db mice heal more slowly than do wounds in C57Bl/6 mice. Healing effects of Regranex seem to be reduced as the consequence of its irritating properties. Carbopol gel interferes with the process of wound healing only in the first three days after the wound induction by increasing the rate of wound retraction. Afterwards it has no effect on the rate of wound contraction.

wound healing; db/db mice

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