In Vivo Evaluation of the Efficacy of a Nisin–Biogel as a New Approach for Canine Periodontal Disease Control

Abstract

Periodontal disease (PD) is a common oral disease in dogs. Recent in vitro research revealed that nisin–biogel is a promising compound for canine PD control. In this work, a clinical trial was developed to assess the in vivo efficacy of nisin–biogel in dogs by determining the dental plaque index (DPI), gingivitis index (GI), and periodontal pocket depth (PPD) after dental administration. The biogel’s influence on aerobic bacteria counts was also evaluated, as well as its acceptance/adverse effects in dogs. Twenty animals were allocated to one of two groups: a treatment group (TG) subjected to a dental topical application of nisin–biogel for 90 days and a control group (CG) with no treatment. Besides daily monitoring, on day 1 (T0) and at the end of the assay (T90), animals were subjected to blood analysis, periodontal evaluation, dental plaque sampling, scaling, and polishing. Statistical analysis with mixed models showed a significant reduction in mean PPD (estimate = −0.371, p-value < 0.001) and DPI (estimate = −0.146, p-value < 0.05) in the TG animals at T90. A reduction in the GI (estimate = −0.056, p-value > 0.05) was also observed but with no statistical significance. No influence on total bacterial counts was observed, and no adverse effects were detected. The nisin–biogel was revealed to be a promising compound for canine PD control.

In Vivo Effect of a Nisin–Biogel on the Antimicrobial and Virulence Signatures of Canine Oral Enterococci

“…Considering that, we believe that the dental application of the nisin–biogel had no direct effect on bacterial counts, and the observed reduction may be attributed to the dental plaque scaling procedure performed on all animals at T0, as suggested by other studies [ 32 , 33 , 34 ]. In fact, the animals from both groups (CG and TC) showed a reduction in their periodontal indices (gingivitis, dental plaque accumulation and periodontal pocket depth) at the end of the clinical trial [ 31 ], which was also related to the scaling procedure, in agreement with the results from the present report.…”

“…This study analysed oral samples obtained from animals that participated in a previous clinical trial [ 31 ] in which the efficacy of the administration of the nisin–biogel for PD prevention in dogs was evaluated. In the present work, enterococci were used as bacterial models to study the in vivo influence of nisin–biogel on virulence and antimicrobial resistance profiles.…”

“…A 1.5% guar-gum biogel ( w / v ) solution was obtained by dissolving 0.75 g of guar gum (Sigma-Aldrich, St. Louis, MO, USA) in 50 mL of sterile distilled water, which was then heat sterilized via an autoclave. Afterwards, nisin was incorporated within the biogel in a proportion of 1:1, in order to obtain a gel with a final concentration of 200 µg/mL to be used in the clinical trial [ 26 , 31 ]. The nisin–biogel concentration was selected based on previous reports regarding its cytotoxicity [ 20 ].…”

“…In this former trial, a total of 20 dogs were selected from an official animal’s rescue institution, according to the Veterinary Oral Health Council (VOHC) instructions for testing compounds aiming at PD prevention. The clinical trial was approved by the Ethical Committee for Research and Teaching (CEIE) of the Faculty of Veterinary Medicine, University of Lisbon, Portugal (N/Ref 014/2020) [ 31 ].…”

“…Animals from the treatment group were submitted to the dental topical application of the nisin–biogel (200 µg/mL) every 48 h; animals from the control group were not submitted to any treatment. Animals were kept in this trial for 90 days [ 31 ].…”