Date Published: July 03, 2020
Publisher: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia
Author(s): Adriana Yuriko Koga, Julio César Felix, Rodrigo Gomes Marques Silvestre, Leandro Cavalcante Lipinski, Bruna Carletto, Fernanda Alexia Kawahara, Airton Vicente Pereira.
To develop a new wound dressing composed of alginate and Aloe vera gel and cross-linked with zinc ions.
The aloe-alginate film was characterized using scanning electron microscopy (SEM), swelling profile, mechanical properties, polysaccharide content and X-ray diffraction (XRD). Thirty Wistar rats were divided in two groups a) treated with aloe-alginate film and b) control (treated with sterile gauze). Wound contraction measurements and hystological analysis were performed on 7th, 14th and 21st days after wound surgery.
The aloe-alginate film presented adequated mechanical resistance and malleability for application as wound dressing. There was no statistical difference in wound contraction between two groups. Histological assay demonstrated that aloe-alginate film presented anti-inflammatory activity, stimulated angiogenesis on proliferative phase and a more significant increased in collagen type I fibers and decreased type III fibers which promoted a mature scar formation when compared to control.
The aloe-alginate film showed adequate physicochemical characteristics for wound dressing applications. The in vivo assay demonstrated that aloe-alginate film enhanced the healing process of incisional skin wounds.
Chronic wounds such as diabetic ulcers, pressure ulcers and venous ulcers affect the quality of life of patients and have a great economic and social impact. The cost increases with the population aging and the incidence of chronic diseases like obesity and diabetes1 .
SEM analysis was performed using a MIRA3 LM, Tescan Orsay Holdingn electron microscope. Prior to analysis, the film samples (cross-linked and non-cross-linked films) were covered with a thin layer of gold by spraying and disposing of a maximum distance to avoid damage to the surface. All the samples were examined using an accelerating voltage of 10 kV.
X-ray diffraction of cross-linked and non-cross-linked aloe-alginate films was performed using an Ultima IV/Rigaku. A scanning rate of 5°/min and range of 3-90° were applied at room temperature.
All the experiments were approved by the Ethics Committee on Animal Experimentation of UEPG, registry number 041/2017. Thirty male Wistar rats (250 g) were divided into the following two groups (n=15): (a) aloe-alginate film and (b) control (sterile gauze). The rats were anesthetized with an i.p. injection of ketamine (40 mg/kg) and xylazine (5 mg/kg).
Tissue of wounds were collected on 7th, 14th, and 21st days and included in paraffin. The tissues samples were cut at a thickness of 3 μm and stained with hematoxylin-eosin. Inflammatory changes and angiogenesis were then observed in three fields under 40 times magnification using a conventional light microscope Olympus. The images were captured using cellSens Standard software. Cell counter image J software was used to count inflammatory cells and blood vessels.
The statistical analysis was performed using analysis of variance (ANOVA) for multiple comparisons, followed by Tukey’s test with a confidence interval of 95% (p ≤0.05).
Aloe vera ( Aloe barbadensis Miller) is a popular medicinal plant for wound healing. Aloe gel contains about 98% of water and polysaccharides constitute 55% of dry matter15 . Acemannan, the major polysaccharide extracted from Aloe vera gel, can stimulate macrophages activation and promote the release of cytokines from fibroblasts16 . The beneficial properties of acemannan in wound healing have been reported17 .
Aloe-alginate film presented adequate physicochemical characteristics for application as wound dressing. The new aloe-alginate film cross-linked with zinc chloride modulated inflammatory phase, increased angiogenesis on proliferative phase and collagen type I suggesting that aloe gel combined with zinc ions contributed to the wound healing process and a better scar formation.