Antifungal efficacy of a synthetic human β-defensin-3-C15 against Candida albicans-infected dentin infection model

Abstract

Objectives The purposes of this ex vivo study were (1) to assess the anti-fungal efficacy of a synthetic human β-defensin-3-C15 (HBD3-C15, 15 amino acids in length) peptide against C. albicans biofilms and (2) to evaluate the drug potential of synthetic HBD3-C15 peptide as a substitute of calcium hydroxide drug in the fungi-infected root canal. In addition, (3) a recent issue regarding the Human Root Dentin Block approach that proposed the usefulness as ex vivo intra-canal fungal infection model was also discussed.

Materials and methods Six millimeter height of human dentin blocks (internal diameter: 0.5 mm) were infected with C. albicans for three weeks. Non-medicament gel (n = 8), satu-rated calcium hydroxide mixed with distilled water (n = 8), non-functional HBD3 peptide gel (n = 8), and synthetic HBD3-C15 peptide gel (n = 8), were tested. After one week of medicament, the debris of dentinal tubules at the depth of 200 and 400 µm were collected using Gates-Glidden drills from root canal lumen. Efficacy of medicaments was assessed by measuring Colony Forming Unit (CFU) of C. albicans after 72 hours of 37°C, 5% CO2 incuba-tion. Data were statistical analyzed with Kruskal-Wallis and Wilcoxon test us-ing SPSS version 23.

Results The synthetic HBD3-C15 peptide group demonstrated significantly lower CFU values than the non-medicament gel group at both depths (p < 0.05). The syn-thetic HBD3-C15 peptide group also shows significantly lower CFU values than the non-functional HBD3 peptide group at both depths (p < 0.05). None-theless, there was no significant difference in the CFU values between syn-thetic HBD3-C15 and calcium hydroxide at both depths (p > 0.05). There was no significant difference in the CFU values of the inner layer and outer dentinal layer for any group (p > 0.05).

Conclusions The synthetic HBD3-C15 peptide has an anti-fungal efficacy against C. albicans biofilms. The synthetic HBD3-C15 peptide showed comparable anti-fungal activity to calcium hydroxide group in C. albicans-infected human root dentin model. The dentin block model effectively reproduced ex vivo situation to evaluate anti-fungal activity of intra-canal medicaments.

Keywords Anti-fungal efficacy, human dentin block, C. albicans biofilms, synthetic hu-man β-defensin-3-C15 peptide, colony forming unit.

Student number 2012-22140