Does Propolis Improve the Regeneration of Bone Critical Defects?

Objectives: The aim of this pilot study was to evaluate the influence of red Propolis and caffeic acid phenethyl ester-enriched Propolis extract (BIO30, New Zealand) mixed to a xenogeneic biomaterial (Bioss, Geistlich, Switzerland), in calvarial critical-size defects.
Methods: Twelve male Wistar rats (180-220 g) were used. The local Animal Ethics Committee (7962) approved the experimental protocols. The animals were divided into four groups: (i) blood clot; (ii) Bioss alone; (iii) BIO30 mixed to Bioss; (iv) Red Propolis mixed to Bioss. A 5-mm inner diameter trephine drill was used (with saline irrigation) to create one full-thickness defect on each side of the brain suture. After the removal of the cortical plates, the defects were filled accordingly to each group. In all of the specimens, one of the defects was covered with a resorbable collagen membrane (Bio-Gide, Geistlich, Switzerland). The animals were euthanized after 4 weeks for sample collection.

Results: Micro-computed tomography analysis showed that both red Propolis/Bioss and BIO30/Bioss presented higher bone regeneration when compared with the blood clot group (P<0.05). However, there was not a significant improvement in comparison with Bioss alone. The histological evaluation of hematoxylin-eosin stained slides did not reveal any significant difference regarding the tissue healing levels when the membrane was used. Otherwise, in the absence of the membrane, the group BIO30/Bioss presented significant higher rates of connective tissue growth in relation to the blood clot group (P<0.05).

Conclusions: In the absence of the membrane, the xenogen biomaterial Bioss improved the bone formation when compared with blood clot, irrespective of the combination with red Propolis or BIO30. Nonetheless, the group BIO30/Bioss displayed a marked buildup of connective tissue in the area within the defect. Further studies are in progress to better characterize this effect.