PROBIOTICS-BASED IRRIGATION SOLUTION: MICROSCOPIC AND MOLECULAR EVALUATION OF EXTRACELLULAR NEUTROPHIL TRAPS EXPRESSION IN TEETH WITH PERIAPICAL LESION INDUCED IN RATS

• Grant number: 22/16612-4
• Support Opportunities: Scholarships in Brazil - Master
• Start date: October 01, 2023
• End date: August 31, 2024
• Field of knowledge: Health Sciences - Dentistry - Pediatric Dentistry
• Principal Investigator: Léa Assed Bezerra da Silva
• Grantee: Ana Paula Gomes e Moura
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Neutrophil extracellular traps (NETs) are one of the ways in which neutrophils act in the host's inflammatory immune response and can lead to exacerbation of tissue damage. At the same time, previous studies have demonstrated the positive effect of probiotics on pulpal infections. However, the effect of probiotics on NETs is still unknown. Thus, the objective of this study will be the microscopic and molecular evaluation of the effect of the probiotic Bifidobacterium animalis subsp. lactis (B. lacti) HN019 used as an irrigating solution for root canals in the expression of NETs after the induction of periapical lesions in rats. After coronary opening and exposure of the pulp tissue to the oral environment, the animals will be divided into four groups and two subgroups according to the irrigation solution, as follows: Group I (9 animals): no treatment; Group II: 2.5% Sodium Hypochlorite (18 animals) IIa one irrigation (9 animals), IIb two irrigations (9 animals); Group III: PBS+Carboxy 2% (18 animals) IIIa one irrigation) and; Group IV: Probiotic (18 animals) IVa one irrigation (9 animals), IVb two irrigations (9 animals). The probiotic Bifidobacterium animalis subsp. lactis (B. lacti) HN019 will be used as irrigating solution by adding 2.7x 109 CFU in 2% carboxymethylcellulose aqueous medium, with a volume of 600µL concomitantly with copious aspiration, and adding a volume of 5µL that will be maintained in the channel. After 21 days of euthanasia, the right hemi-jaws and hemi-mandibles will be processed for microscopic and molecular analysis. The slides will be stained in hematoxylin and eosin (HE) and analyzed in optical microscopy for neutrophil count, histomorphometry of the area of the periapical lesions and indirect immunofluorescence for labeling the enzymes ELANE (elastase), histone H3, myeloperoxidase (MPO) and CRAMP (LL 37 homologue). The right hemi-jaws will be processed for the Real-time polymerase chain reaction (RT PCR) to evaluate elastase, histone H3, MPO and CRAMP mRNA expression. Data will be submitted to statistical analysis through appropriate tests according to the nature of the data. For all analyses, a significance level of 5% will be adopted.