Evaluation of chemokines and receptors in gnotobiotic root canal infection by F. nucleatum and E. faecalis

Abstract

The present study aims to evaluate the longitudinal effects ofinduced experimental infections in gnotoxenic animals on the expressionof inflammatory chemokines and their receptors in periradicular tissues.The null hypothesis tested was that Enterococcus faecalis and Fusobacteriumnucleatum had no effect on CCR5, CCL5, CXCL10, CCL2/MCP-1, CXCR2and CCR1 expression. Two groups of five animals (n = 5) aged between8 and 12 weeks were used in this study. The animals were anaesthetized,and coronary access was performed in the first molar on the right and leftsides. Microorganisms were inoculated into the left molar, and the rightmolar was sealed without contamination to function as a control. Animalswere sacrificed 7 and 14 days after infection, and periapical tissues werecollected. The cytokine mRNA expression levels were assessed using realtimePCR. The chemokine mRNA expression levels demonstrated thatthe experimental infection was capable of inducing increased chemokineexpression on day 7 compared to that on day 14, except for CCR5 andCCL5, which showed no changes. The gnotoxenic animal model provedto be effective and allowed evaluation of the immune response againsta known infection. Additionally, this study demonstrates that geneexpression of chemokines and their receptors against the experimentalinfection preferentially prevailed during the initial phase of induction ofthe periradicular alteration (i.e., on day 7 post-infection)