Dentistry

Abstract

The Therapeutic Use of Propolis Extract in Alveolar Bone Contaminated with Bacterial Endotoxin

Yamba Carla Lara Pereira, João Paulo Mardegan Issa, Evandro Watanabe, Glauce Crivelaro Nascimento, Mamie Mizusaki Iyomasa, José Orestes Del Ciampo and Edilson Ervolino

Propolis is a resinous substance obtained by bees, whose antibacterial, anti-inflammatory, antiviral, antifungal, immune stimulant, and local anesthetic wound healing properties have been considered for clinical practice. In particular, its anti-inflammatory and antibacterial characteristic seems to be a novel target for infectious process from dental origin. This work aimed to evaluate the propolis antibacterial potential against a bacterial endotoxin on dental alveoli. First, some properties of green propolis extract were analyzed (in vitro): 1) physicochemical profile 2) Minimum Inhibitory Concentration (MIC) against endotoxin from Gram negative Escherichia coli, and 3) its immunoregulatory activity on leukocytes from the spleen of rats. Then, an inflammatory process was induced in rats by a contamination with lipopolysaccharide (LPS) that is recognized as an endotoxin. For this purpose, rats were subjected to extractions of maxillary first molars, right and left, which immediately had the right dental socket contaminated with 0.1L of LPS (100 μg/kg). After 14 days from exodontia, these individuals were divided in groups treated with Pure Propolis Extract (EPP) and groups without therapy. The contaminated alveolar bone or the same area from animals without inflammation-induced were removed for histological and immunohistochemical processing. Our data reveal an important therapeutic action from green propolis. In vitro tests indicated low cytotoxicity for this compound. By a hematoxilin and eosin analysis, the group infected and treated with propolis presented the alveoli with more new bone tissue, characterized by bony trabeculae circling small cavities filled by a loose connective tissue containing blood vessels. Additionally, a histochemical marker of osteoclasts, tartrateresistant acid phosphatase (TRAP), was used to determine the new bone formation rate. The propolis induced more TRAP formation on alveolar bone infected by LPS. Our findings highlight the potential of propolis to be applied in dental material.