Use of insulin-like growth factor in the healing of open wounds in diabetic and non-diabetic rats

ABSTRACT

To analyze the effects of application of 1% and 3% insulin-like growth factor I (IGF-1) cream on the process of wound healing in induced skin lesions in diabetic and non-diabetic rats and evaluate its effect on expression of myofibroblasts. METHODS: Ninety-six Wistar adult male rats were divided into six groups, with 16 rats in each group, as follows group 1 non-diabetic, untreated; group 2 non-diabetic, treated with 1% IGF-1 cream; group 3 non-diabetic, treated with 3% IGF-1 cream; group 4 diabetic, untreated; group 5 diabetic, treated with 1% IGF-1 cream; and group 6 diabetic, treated with 3% IGF-1 cream. In groups 4, 5, and 6, diabetes was induced by intravenous injection of alloxan. After diabetes had been induced, animals were mantained for 3 months. The experimental procedure consisted of the creation of a circular incision of 0.9 mm in diameter using a metal punch. Following this, wounds were treated daily according to the assigned treatment regimen. Groups 2 and 5 were treated with 1% IGF-1 cream, groups 3 and 6 with 3% IGF-1 cream, and groups 1 and 4 and the untreated groups with 0.9% saline solution. From each group, samples from 4 rats were taken at three, seven, 14, and 21 days after the injury. Samples were fixed in 10% formalin to prepare slides for histological analysis. Slides stained with hematoxylin-eosin (H&E) and Masson were observed vascular proliferation, mononuclear cells, polymorphonuclear cells, fibroblast proliferation, re-epithelialization, and collagen fibers. This study analyzed the expression of α-smooth muscle actin using specific antibodies to correlate the temporal expression of α-smooth muscle-specific actin (α-SM actin), a molecular marker for myofibroblast transformation. RESULTS: Macroscopic observation of wounds showed a more rapid re-epithelialization of wounds treated with IGF. Regarding acute inflammatory reactions, the results of the analysis of vascular.