Treatment of experimentally induced partial-thickness burns in rats with different silver-impregnated dressings

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.

Figure 1. Macroscopic aspects of partial thickness burn wounds experimentally induced in Wistar rats treated with silver-based dressings through 7 days.

Figure 2. Macroscopic aspects of partial thickness burn wounds experimentally induced in Wistar rats treated with silver-based dressings through 14 days.

Figure 3. Macroscopic aspects of partial thickness burn wounds experimentally induced in Wistar rats treated with silver-based dressings through 30 days.

Figure 4. Microscopic aspects of partial thickness burn wounds experimentally induced in Wistar rats and treated with silver-based dressings 7 DAI, scale bar = 200 μm.

Figure 5. Microscopic aspects of partial thickness burn wounds experimentally induced in Wistar rats and treated with silver-based dressings 7 DAI, scale bar = 50 μm.

Figure 6. Microscopic aspects of partial thickness burn wounds experimentally induced in Wistar rats and treated with silver-based dressings 14 DAI, scale bar = 200 μm.

Figure 7. Microscopic aspects of partial thickness burn wounds experimentally induced in Wistar rats and treated with silver-based dressings 14 DAI, scale bar = 50 μm.

Figure 8. Microscopic aspects of partial thickness burn wounds experimentally induced in Wistar rats and treated with silver-based dressings 30 DAI, scale bar = 200 μm.

Figure 9. Microscopic aspects of partial thickness burn wounds experimentally induced in Wistar rats and treated with silver-based dressings 7 DAI, scale bar = 50 μm.

Figure 10. Collagen fibers deposition in partial thickness burn wounds experimentally induced in Wistar rats and treated with silver-based dressings 7 DAI. Type I collagen fibers are shown in red and type III collagen fibers are shown in green.

Figure 11. Collagen fibers deposition in partial thickness burn wounds experimentally induced in Wistar rats and treated with silver-based dressings 14 DAI. Type I collagen fibers are shown in red and type III collagen fibers are shown in green.

Figure 12. Collagen fibers deposition in partial thickness burn wounds experimentally induced in Wistar rats and treated with silver-based dressings 30 DAI. Type I collagen fibers are shown in red and type III collagen fibers areshown in green.