Wound collagen accumulation in obese hyperglycemic mice

We used C57-BL ob/ob mice as a model to study wound healing in type II (adult-onset) diabetes. Planimetry was used to assess rate of closure in standard open skin wounds. In agreement with previous subcutaneous wound collagen-accumulation studies, closure was slower in the ob/ob mice. Subcutaneous implants were used to evaluate wound collagen accumulation. Weanling mice have collagen accumulation similar to lean littermates (mean 3.43 micrograms/cm vs. 3.46 micrograms/cm), but the same ob/ob animals had decreased wound collagen (mean 2.39 micrograms/cm vs. 3.02 micrograms/cm, P less than 0.04) when mature. Other ob/ob animals fed a restricted diet (and thus not obese) had normal collagen accumulation at the same age. Neither insulin nor diet restriction restored wound collagen accumulation in phenotypically obese mice. Because collagen accumulation is not improved by measures that control hyperglycemia (insulin and diet restriction) and the defect was seen only in phenotypically obese ob/ob mice, the decreased wound collagen accumulation may be due in part to structural changes in adipose tissue.