Establishment of a protocol for induction of experimental periodontal disease in murines by Aggregatibacter actinomycetemcomitans

• Grant number: 13/06036-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): September 01, 2013
• Effective date (End): August 31, 2015
• Field of knowledge: Health Sciences - Dentistry - Periodontology
• Principal Investigator: Marcia Pinto Alves Mayer
• Grantee: Natália de Oliveira Neves
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Aggregatibacter actinomycetemcomitans is associated the etiology of localized aggressive periodontitis and it presents several virulence factors, mainly adherence and invasion on epithelial cells, production of leukotoxin and cytolethal distending toxin. In mice used as experimental animal model, the inoculation of the smooth afimbriated variant in the oral cavity and in the gingival tissues induced alveolar bone loss, although the bacterium was detected only by PCR from gingival tissues and not from teeth and mucosa surfaces. In rat model, the inoculation of rough variant induced the colonization of the oral cavity, differing from the smooth variant. Different species of animals and even different strains within the same species can exhibit differ on their susceptibility to infection by pathogenic bacteria and to development of disease. Thus, the objective of this study is to test the hypothesis that a serotype b strain of A. actinomycetemcomitans, with fimbriated phenotype, would be able to colonize the oral cavity and to induce periodontitis in a murine animal model. Methods: a JP2 like A. actinomycetemcomitans isolate, with rough phenotype, obtained from the human oral cavity, will be inoculated into mice of three different lineages C3H/HeJ, C57 Black C and Balb C. Six mice of each lineage will be randomized into 2 subgroups (n = 3), infected and control. Periodontal disease will be induced by oral inoculation of viable fimbriated cells of A. actinomycetemcomitans after culture in liquid medium. After 60 days of the last oral inoculation, the animals will be sacrified. The morphological pattern of periodontal structures, cytokines profile (IL-6, IL-10 and IL-12) in the gingival tissues and in the serum of animals, and levels of A. actinomycetemcomitans in gingival tissue, tooth and mucosa surfaces will be evaluated. (AU)