Validation of a Model for the Study of Multiple Wounds in the Diabetic Mouse (db/db)

Abstract

The genetically diabetic db/db mouse exhibits symptoms that resemble human type 2 diabetes mellitus, demonstrates delayed wound healing, and has been used extensively as a model to study the role of therapeutic topical reagents in wound healing. The purpose of the authors' study was to validate an excisional wound model using a 6-mm biopsy punch to create four full-thickness dorsal wounds on a single db/db mouse. Factors considered in developing the db/db wound model include reproducibility of size and shape of wounds, the effect of semiocclusive dressings, comparison with littermate controls (db/-), clinical versus histologic evidence of wound closure, and cross-contamination of wounds with topically applied reagents. The size of wounds was larger, with less variation in the db/db mice (31.11 +/- 3.76 mm2) versus db/- mice (23.64 +/- 4.78 mm2). Wounds on db/db mice that were covered with a semiocclusive dressing healed significantly more slowly (mean, 27.75 days) than wounds not covered with the dressing (mean, 13 days; p < 0.001), suggesting the dressings may splint the wounds open. As expected, wounds healed more slowly on db/db mice than db/- mice (covered wounds, 27.75 days versus 11.86 days, p < 0.001; wounds not covered, 13 days versus 11.75 days, p = 0.39). Covered wounds, thought to be closed by clinical examination, were confirmed closed by histology only 62 percent of the time in the db/db and 100 percent of the time in the db/- mice. Topical application of blue histologic dye or soluble biotinylated laminin 5 to one of the four wounds did not spread locally and contaminate adjacent wounds. Multiple, uniform, 6-mm wounds in db/db mice heal in a relatively short time, decrease the number of animals needed for each study, and allow each animal to serve as its own control. The db/db diabetic mouse appears to be an excellent model of delayed wound healing, particularly for studying factors related to epithelial migration.

Blockade of TSP1-Dependent TGF-β Activity Reduces Renal Injury and Proteinuria in a Murine Model of Diabetic Nephropathy

“…63,67 To address the effect of long-term LSKL therapy on other TGF-␤-mediated functions in diabetes, we studied dermal wound healing in a well-established model of diabetic wound healing in type 2 diabetic mice. 44 TGF-␤ signaling is known to be impaired in diabetic skin wounds, resulting in reduced macrophage chemoattraction, angiogenesis, and extracellular matrix deposition with accelerated reepithelialization. 68,69 Treatment of diabetic wounds with active TGF-␤ normalizes wound healing.…”

“…The wounds were covered with the semiocclusive dressing until harvest to decrease tissue contraction and better assess reepithelialization. 44 There were no differences in the rate of wound closure more than 22 days after wounding in mice receiving i.p. injections of either LSKL or saline or s.c. nonimmune IgG ( Figure 8A).…”

“…44 Mice male (BKS.Cg-m ϩ/ϩ Lepr db /J), (db/db) at approximately 10 weeks of age were anesthetized, the skin was cleaned, and hair on the dorsal skin was removed. Under sterile conditions, two 4-mm-diameter circular, full-thickness wounds, 2 cm apart, were generated on the back of each mouse at the same craniocaudal level using a dermal punch (Acuderm Inc., Fort Lauderdale, FL).…”

Heparin-binding domain of fibrin(ogen) binds growth factors and promotes tissue repair when incorporated within a synthetic matrix

“…We then evaluated the synthetic matrix in vivo. We used the db/db mouse, which is a genetic mouse model of diabetes that provides a well-established and clinically relevant experimental system of impaired wound healing (22,23). We treated full-thickness back skin wounds of these mice with GFs (FGF-2 and PlGF-2, 200 ng of each) delivered by a fibrin matrix or by the fibrin-mimetic matrix.…”

Topical application of laminin-332 to diabetic mouse wounds

“…Genetically diabetic (db/db) mice have been used extensively as a model to study wound healing as it relates to diabetes mellitus and the role of therapeutic topical reagents in wound healing (4)(5)(6)(7). The db/db mice have an autosomal recessive mutation that results in defective leptin receptors in the hypothalamus.…”