Kefir de leite liofilizado : caracterização microbiológica e avaliação do efeito osteoprotetor em diferentes tempos de fermentação em ratos com periodontite

Abstract

Periodontitis is characterized by chronic inflammation and alveolar bone loss (ABL), triggered by an exacerbated immune response to a dysbiotic bacterial biofilm. Scaling and root planing are considered the gold standard for treating this disease, and antibiotic therapy is recommended as an adjunct in more severe cases, although it may cause systemic adverse effects. Given this, the investigation of safer therapies, such as probiotics, appears promising. Milk kefir (MK), commonly administered after 24 hours of fermentation, has shown anti-inflammatory and antiresorptive effects in experimental periodontitis after four days of fermentation in a previous study by our group, albeit with compromised organoleptic properties.This study is divided into two chapters. The first chapter conducted a microbiological characterization of lyophilized milk kefir (LMK) and MK at different fermentation times (1, 4, and 7 days) and evaluated the effect of LMK on inflammatory bone disease in rats. Metagenomic analyses were performed on MK and LMK samples fermented for 1, 4, and 7 days to determine the microbial composition using the V4 region of the 16S rRNA gene and the V9 region of the 18S rRNA gene.Additionally, 30 male Wistar rats were divided into five experimental groups (n=6): control (C), experimental periodontitis (EP), and three groups that received LMK (1, 4, and 7 days of fermentation; LMK1, LMK4, and LMK7, respectively). LMK was administered daily for 28 days before EP induction and throughout disease progression (11 days), totaling 39 days. EP was induced by placing a ligature around the left upper second molar. After euthanasia, the hemimaxillae were subjected to histopathological, histomorphometric, and immunohistochemical analyses for RANK, RANKL, and OPG in periodontal tissues.MK and LMK exhibited distinct bacterial and fungal compositions at different fermentation times, with LMK fermented for 7 days showing a significant presence of the Rhizobiaceae and Malassezia families. Furthermore, at this fermentation time, animals with periodontitis exhibited less inflammatory infiltration, greater preservation of the supporting periodontium, and an increased number of osteoblasts. A significant increase in ABL and immunoexpression of RANK and RANKL and a reduction in OPG were observed in all animals with EP. Animals that received LMK fermented for 4 and 7 days showed lower ABL (50% and 70%, respectively), and a 50% reduction in the RANK/RANKL ratio and an 82% reduction in the RANKL/OPG ratio were observed in the LMK7 group compared to the EP group. LMK, especially after 7 days of fermentation, demonstrated a greater osteoprotective effect in animals with EP. The second chapter of this thesis presents the patent filing BR 10 2024 017721 5, related to the production, pharmaceutical composition, and use of milk kefir as an adjuvant treatment periodontitis.