Impact of commensal flora on periodontal immune response to lipopolysaccharide

• Published in: Journal of periodontology (1970) 2018-10, Vol.89 (10), p.1213-1220
• Main Authors: Fukuhara, Daiki, Irie, Koichiro, Uchida, Yoko, Kataoka, Kota, Akiyama, Kentaro, Ekuni, Daisuke, Tomofuji, Takaaki, Morita, Manabu
• Format: Article
• Language: English
• Subjects: animal model; Dentistry; immune system; lipopolysaccharide; microbiota
• ISSN: 0022-3492; 1943-3670
• DOI: 10.1002/JPER.17-0567

Background Commensal flora are involved in the appropriate development of the mature immune system. However, it is unclear how commensal flora contribute to immune responses against periodontal pathogens, including the response to lipopolysaccharide (LPS). The purpose of this study was to evaluate the expression of immune responses after topical application of LPS in germ‐free (GF) and specific‐pathogen‐free (SPF) mice. Methods GF and SPF mice at 8 weeks of age were randomly divided into four groups each: a baseline group (n = 4/group) and three experimental groups (n = 6/group). Experimental groups received topical application of Porphyromonas gingivalis LPS (10 μg/μL) into the palatal gingival sulcus. Sampling was performed before LPS application (baseline) and at 3, 24, or 72 hours after LPS application. The numbers of neutrophils, CD4+, and CD8+ T cells in periodontal tissue were evaluated by immunohistochemistry. Expression of genes encoding cytokines, chemokines, and a transcription factor was determined by real‐time PCR. Results SPF mice, but not GF mice, showed an increased number of CD4+ T cells in the periodontal tissue at 3 hours after LPS application, compared with the number at baseline (p