Comparative Study of the Effects of Topically Used Insulin and Simvastatin on Thermal Induced Burn in Diabetic Albino Rats

Abstract
Background: Diabetic wound healing is a major compli-cation that may be delayed or impaired. This is resulting from abnormalities in inflammatory and oxidative stress responses, impaired growth factors production, angiogenic responses and collagen deposition.
Aim of the Work: The aim of this work was to investigate and compare possible effects of topical insulin and simvastatin on the tissue repair capacity, their anti-inflammatory and anti-oxidant effects.
Material and Methods: Sixty male Wister Albino rats were divided into 5 equal groups, group1 normal burned received vehicle, group 2 diabetic burned received vehicle, group 3 diabetic burned received insulin in vehicle, group 4 diabetic burned received simvastatin in vehicle and group 5 diabetic burned received insulin in saline all applied topically. At certain end recording points (3rd, 7th, 14th and 21st days post burning) wound contraction percentage % was calculated and serum tumor necrosis factor-a (TNF-a), blood reduced glutathione and serum malonaldialdehyde (MDA) levels were estimated and dissected burn specimens were prepared for histopathological and immunohistochemical staining for VEGF and a-SMA.
Results: Insulin and simvastatin produced more than satisfactory results evidenced by significant improvement in the whole studied parameters.
Conclusion: Insulin and simvastatin have anti–inflamma-tory, antioxidant and angiogenic effects improving the healing properties. Although they both in vehicle exhibited similar effectiveness in regard the investigated parameters, they exhibited superiority over insulin in saline.