Efeitos da terapia probiótica (Bacillus subtilis) sobre parâmetros metabólicos e inflamatórios em ratos com periodontite induzida por ligadura associada ou não ao estresse crônico

Abstract

Periodontal disease is characterized by chronic inflammation of the tissues supporting the teeth, depending on the host response, in reaction to the presence of periodontal pathogens in sub-gingival biofilm. Local and systemic measures modulation of the immune response and of microbial environment has been investigated. In this context emerge probiotics which are live organisms that when administered in adequate amounts give beneficial health effects, arousing the interest of its application in periodontal therapy. The present study was divided in two chapters. In the first, it was made a systematic review evaluating the probiotics effect on immune response in rats submitted to different experimental challenges. The survey was using PubMed, ISI Web of Science and Scielo databases. The bacteria species most used were Lactobacillus and Bifidobacterium. Eighty-six percent of the selected articles reported a beneficial effect on the immune response associated to the probiotics use. In the second chapter it was evaluated the probiotic therapy effect in rats with periodontal disease induction associated with restriction stress. The experimental design was completely randomized factorial 2x2x2 (with and without periodontal disease (PD), with and without chronic stress (CS), with and without probiotics use) with six replicates in each group. The probiotic Bacillus subtilis was administered orally at 1.5 x 108 proportion of colony-forming units (CFU)/mL to the drinking water of the animals for 45 days. The CS was performed by immobilization daily for 2.5 hours from the 16th day during 30 days, while the PD was induced by the ligation protocol in the first right and left mandibular molars from 31st day for 14 days. Villus height and crypt depth of the duodenum, jejunum and ileum were measured. Euthanasia was performed on the 45th day of the experiment. The significance level was set at p<0.05. PD increased alveolar bone loss, levels of cyclooxygenase-2 (COX-2), carboxyterminal telopeptide of collagen type-1 (CTX), p38 mitogen-activated kinases (MAPK), ligand receptor activator of NF-κB (RANKL) and decreased levels of osteoprotegerin (OPG) (p<0.05). The stressed rats had higher levels of C-peptide, corticosterone and glucose (p<0.05). The presence of stress decreased expression of p38 and CTX (p<0.05). The probiotic reduced alveolar bone loss in the non-stressed rats, as well as decreased expression of CTX and induced the increased expression of OPG in unstressed rats with PD (p<0.05). Although the probiotic has not been effective in preventing bone loss or alteration of the expression of inflammatory markers in stressed rats, the number of inflammatory cells decreased (p<0.05). Groups with stress and PD showed decrease in villous height and depth of intestinal crypts (p<0.05). In general conclusion, probiotics were beneficial in the modulation of immune response and have a promising in the control of periodontal disease.