Short time insulin treatment post burn improves elastic-collagen rearrangement and reepithelization

Abstract

Extensive burn may cause acute resistance to insulin, which accentuates hypermetabolism, impairs glucose metabolism, immune dysfunction and risks of sepsis. To minimize these effects, insulin is used as a treatment. The purpose was to analyze the collagen-elastic arrangement effects of insulin on the burned skin. Wistar rats were assigned in groups: control (C); control with insulin (C + I); scald burn injury (SBI); and SBI with insulin (SBI+ I). SBI were submitted to 45% total body surface area burn and the insulin-treated groups received insulin (5 UI/Kg/day) for 4 or 14 days (d). Insulin levels, glucose tolerance test and HOMA index were determined. The skin sections were analyzed for histophatological and morphoquantitative data. Histopathological findings showed increased reepithelization of SBI+ I and formation of a new muscle layer after 14 days. In the collagen-elastic arrangement, insulin for 4 days increased the volume fraction (Vv) of thin collagen and elastic fibers. After 14 days, independently of injury, insulin decreased the elastic fibers. Insulin was able to reverse damages in the collagen-elastic rearrangement and stimulate reepithelization after 4 days. Untreated scald-burned animals showed higher Vv of thick collagen after 4 days, while those treated had a higher Vv of thin collagen. The Vv of elastic fibers was increased in SBI+ I for 4 days. In conclusion, insulin treatment was able to stimulate reepithelization. It also reversed the damages to the collagen-elastic arrangement in the scald-burned group, improving the organization of thin collagen and increasing the Vv of elastic fibers in the injured group treated with insulin for a short time, that is, for 4 days.

Topical Insulin Modulates Inflammatory and Proliferative Phases of Burn-Wound Healing in Diabetes-Induced Rats

“…In a previous study, we reported that topical insulin increased Type I collagen fibers and improved organization and the rate of healing in second-degree burns (Azevedo et al, 2015). Our findings corroborate those of Baptista et al (2018), who observed that scald-burn injuries in diabetic animals improved after 4 days of topical insulin treatment (5 U/kg/day) due to the rearrangement of elastic−collagen fibers rearrangement and reepithelization of injured tissue. Taken together, these data confirm the capacity of topical insulin to modulate components of the extracellular matrix, leading to increased speed of wound closure.…”

“…Currently, it is among the promising treatments for burn wounds among patients with diabetes (Hrynyk & Neufeld, 2014; Lima et al, 2012; Oryan & Alemzadeh, 2017; Wu et al, 2009). Studies have shown that, compared to burn wounds in patients with diabetes not treated with insulin, those treated with insulin have faster closure with a diminished inflammatory phase, improved formation of granulation tissue, and collagen fibers organized in meshes in a characteristic pantographic pattern similar to healthy skin (Azevedo et al, 2015; Baptista et al, 2018; Hrynyk & Neufeld, 2014; Oryan & Alemzadeh, 2017). The mechanism by which insulin enhances the rate of wound healing in patients with diabetes, however, is not completely understood.…”

Insulin Modulates Myogenesis and Muscle Atrophy Resulting From Skin Scald Burn in Young Male Rats

“…Our research group found improvement in elastic-collagen rearrangement and reepithelization in short-term insulin treatment when comparing short-and long-term insulin treatments in burn-injured skin. 25 However, in this study, we investigated the effects of insulin treatment on a muscle distant from extensive burn lesion. Regarding experimental studies on extensive BIs and intensive insulin therapy, most authors studied short-term therapy acting in the acute postburn phase, ranging from 1 to 5 d. [30][31][32][33][34][35][36] Few Fig.…”

“…The insulin dosage used was chosen based on studies whose authors administered insulin treatment in euglycemic murine models. 24,25 Insulin-treated rats received 5% sucrose in drinking water to maintain euglycemia. 26 The weight and water and food intake of all animals were recorded every day since weaning, which included the days of adaptation in individual cages.…”

Downregulation of miR‑27b promotes skin wound healing in a rat model of scald burn by promoting fibroblast proliferation

“…Collagen is an extracellular fibrin that promotes the formation of the intracellular matrix and repair of damaged cell structures ( 31 ). Type I and III collagen are the major components of collagen in the ECM and serve a major role in wound healing ( 32 ). The results of the present study demonstrated that miR-27b inhibition significantly upregulated the mRNA and protein expression of collagen I and III in scalded skin tissues of rats and in BJ cells, which may be associated with the accelerated healing of scalded skin in rats.…”