Expressão de genes e quantificação de Lactobacillus paracasei e Lactobacillus rhamnosus presentes em lesões dentinárias de crianças com cárie da primeira infância

Abstract

Lactobacillus paracasei and Lactobacillus rhamnosus belong to the group Lactobacillus casei and are strongly associated with the progression of caries, especially in dentin, and considering that food/probiotic consumption is an important source of Lactobacillus. This study aimed to analyse the expression profile of genes related to adhesion (spaC and spaE), extracellular polymeric substance regulation (wzb) and pyruvate oxidation (spxB) of the L. paracasei and L. rhamnosusas well as to detect and quantify the L. casei group, L. paracasei and L. rhamnosus bacteria in active and arrested dentin caries lesions of children with early childhood caries (ECC). Total RNA was extracted from dentin samples (25 active and 13 arrested lesions) of pre-school children with ECC aged 3–5 years. The samples were converted to cDNA and qPCR analyses were performed for bacterial quantification and gene expression analyses. Student’s t-test or Mann-Whitney U test were used for mean comparisons of the groups. The L. casei group species were found to be part of the viable microbial community in dentin caries lesions, with the L. casei group (p= 0.004), L. paracasei (p= 0.001), and L. rhamnosus (p= 0.022) being more abundant in active dentin lesions compared to the arrested ones. Gene expression data revealed spaC, spxB and spaE were equally expressed regardless of the caries lesion activity (p>0.05), while the wzb gene (p= 0.006) showed higher expression in active dentin lesions. This study provides insights about oral microbiota related to dentin caries activity status, indicating that the L. casei group, and the species L. paracasei and L. rhamnosus can have different behavior in active and inactive lesions and may be linked to dentin lesion progression and activity.