ABSTRACT Purpose: To compare four commercially available hydrogel formulations in the healing of partial thickness burns experimentally induced in rats. Methods: Wistar rats were used, and after the burn wound induction they were divided into the following treatment groups: G1) NaCl 0.9%; G2) 1% silver sulfadiazine; G3) Debrigel™; G4) Safgel™; G5) Dersani™; G6) Solosite™. The animals were followed during seven, 14 and 30 days after the injury induction. Morphometric, macroscopic and microscopic evaluations were performed. Results: The treatment with Dersani™ induced better results during the inflammatory and proliferative phases of the healing process (p<0.05). The animals treated with Safgel™ presented better scaring in the remodeling phase (p<0.05), and the treatment with Dersani™ and Solosite™ induced greater wound closure (p<0.05). Conclusions: The hydrogel-based dressings presented beneficial outcomes in the healing of burn wounds experimentally induced in rats due to their ability in maintain the humidity of the wound, in removing the exudate, in promoting cell migration and collagen production during the different phases of the healing process.

ABSTRACT Purpose: To evaluate the morphometric, macroscopic and microscopic aspects of experimentally induced partial-thickness burns in rats treated with different silver-based dressings. Methods: Wistar rats were used, divided into six treatments: saline (NaCl 0.9%); silver sulfadiazine 1%; Silvercel; Mepilex Ag; Aquacel Ag and Acticoat. The animals were monitored daily and euthanized at 7, 14 and 30 days after injury induction (DAI). Results: At 7 DAI, necrosis/crust was greater in control, silver sulfadiazine and Mepilex Ag treatments, granulation tissue was induced by Aquacel Ag, polymorphonuclear infiltrate (PMN) infiltration was intensified by Mepilex Ag; mononuclear infiltrate (MN) infiltration and angiogenesis were increased by Silvercel. At 14 DAI, hemorrhage was decreased by Silvercel and Mepilex Ag, PMN infiltration increased by Acticoat. At 30 DAI, angiogenesis was greater in the Acticoat treatment and fibroblasts were increased by Acticoat and Mepilex Ag. Collagen was induced at 14 DAI by silver sulfadiazine and Aquacel Ag and, at 30 DAI, by silver sulfadiazine and Silvercel treatments. Conclusions: Silvercel and Acticoat presented better results than the other products. However, all the dressings were better than the control at some point during the process, and may contribute to the healing of partial thickness burns. Silvercel and Aquacel Ag treatments induced better cosmetic outcomes regarding wound closure and scarring.

ABSTRACT Purpose This study aimed to elaborate a hydrogel constituted by carboxymethyl chitosan (CMC), hyaluronic acid (HA) and silver (Ag) and to evaluate its healing effect on partial-thickness burn wounds experimentally induced in rats. Methods CMC was obtained by chitosan reacting with monochloroacetic acid. The carboxymethylation was confirmed by Fourier-transform infrared spectroscopy and hydrogen nuclear magnetic resonance (NMR). Scanning electron microscopy was used to determine the morphologicalcharacteristics of chitosan and CMC. After the experimental burn wound induction, the animals (n = 126) were treated with different CMC formulations, had their occlusive dressings changed daily and were followed through 7, 14 and 30 days. Morphometric, macroscopic and microscopic aspects and collagen quantification were evaluated. Results Significative wound contraction, granulation tissue formation, inflammatory infiltration and collagen fibers deposit throughout different phases of the healing process were observed in the CMC hydrogels treated groups. Conclusions The results showed that, in the initial phase of the healing process, the most adequate product was the CMC/HA/Ag association, while in the other phases the CMC/HA association was the best one to promote the healing of burn wounds.