The incorporation of Brazilian propolis into collagen-based dressing films improves dermal burn healing

Ethnopharmacological relevance: Hydroalcoholic solutions of propolis, a resinous product produced by bees, have been currently employed in improving the cicatricial repair. Biological activity of propolis might be related to its antimicrobial, anti-inflammatory and immunomudalatory properties. Aim of this study: Investigate the suitability of the collagen-based films containing hydroalcoholic extracts of two different varieties of Brazilian propolis (green and red ones) on the dermal burn healing in rodent model. Materials and methods: The hydroalcoholic extracts of red propolis (RP) or Green propolis (GP) were incorporated into collagen-based dressing films (COL). Burn wounds were performed in the dorsum of Wistar rats and dressing with COL, COL+GPa (0.5%), COL+GPb (1,0%) or COL+RP (0.5%). A control group (CTR) was performed keeping the wound undressed. The histological analyses were carried out after 3, 7, 14, 21 and 30 days for histological assessment of the inflammatory response, epithelization rates (ER), myofibroblastic count (MC) and collagenization pattern. Results: GPa, GPb and RP provided significant decrease of the inflammatory severity, improved the ER in GPa in 7 (p=0.000),14 (p=0.000), 21 (p=0.005) and 30 days (p=0.015), and induced earlier replacement of type-III for type-I collagen (p<0.05) than COL and CTR. In all the groups, the MC increased progressively from 3 to 14 days, and then started to decrease slowly until 21 days. Although no significant difference was observed among the groups in 3, 7 and 30 days, the MC was significantly increased in RP in 14 (p=0.0001) and 21 days (p=0.04), as well as grosser interlacement of the collagen bundles compared with the other groups. Conclusion: The incorporation of hydroalcoholic extracts of Brazilian propolis improved the biological events associated to burn healing without toxic effects, but the red variety provided the best results. Therefore, these collagen-based containing natural apicultural products films may be considered a promising new dressing for wound occlusion and tissue repairing. (C) 2013 Elsevier Ireland Ltd. All rights reserved.