Evaluation of the Effects of Bismuth Subgallate on Wound Healing in Rats. Histological Findings

Introduction Bismuth subgallate (BS) is a yellow and odorless powder that has hemostatic astringent properties. Some otorhinolaryngologists and dentists currently use this substance to enhance wound healing. Objective The objective of this study is to evaluate the effects of bismuth subgallate on wound healing, through the analysis of inflammatory process, collagen production, and angiogenesis. Method A standard wound was made on the back of 60 male Wistar rats, using a biopsy punch. We created two groups: the experimental group, which underwent daily application of 0.5mg BS over the entire wound, and the control group, which underwent daily application of sodium chloride 0.9%. We performed a qualitative evaluation of the tissue on the third, seventh, and fourteenth day. We assessed inflammatory markers using Hematoxylin and Eosin (HE) stain, used Picrosirius stain for collagen analysis, and immunohistochemistry was used for angiogenesis analysis through evaluation of smooth muscle proliferation. Results Statistically, we found no significant differences between groups regarding inflammatory response on the third (p = 1), seventh (p = 0.474), and fourteenth day (p = 0.303). Also, collagen type I and III production showed no statistical differences between groups on the third (p = 0.436), seventh (p = 0.853), and fourteenth day (p = 0.436) of analysis. Immunohistochemistry did not present differences on angiogenesis between experimental and control group on the third (p = 0.280), seventh (p = 0.971), and fourteenth day (p = 0.218). Conclusion BS does not promote significant changes in inflammatory response, collagen, and angiogenesis. Thus, it does not influence healing on skin wounds on rats.