Butyric acid modulates periodontal nociception in Porphyromonas gingivalis-induced periodontitis

Purpose: Periodontitis progresses with chronic inflammation, without periodontal pain. However, the underlying mechanisms are not well known. Here, the involvement of butyric acid (BA) in periodontal pain sensitivity in Porphyromonas gingivalis (P. gingivalis)-induced periodon-titis was examined. Methods: P. gingivalis was inoculated into the ligature which was tied around the molar (P. gingivalis-L) and the gingival mechanical head with-drawal threshold (MHWT) was measured. Following P. gingivalis-L, the expressions of orphan G protein-coupled receptor 41 (GPR41) in trigemi-nal ganglion (TG) neurons were examined. The amount of gingival BA was analyzed following the P. gingivalis-L and the changes in the MHWT in complete Freund’s adjuvant (CFA)-injected gingival tissue by gingival BA were examined. The changes in the MHWT following P. gingivalis-L by gingival GPR41 antagonist (HA) were examined. Results: No change in the MHWT was observed, GPR41-immunoreactive TG neurons were increased following P. gingivalis-L. The gingival BA amount increased following P. gingivalis-L, and the gingival BA sup-pressed the decrease in MHWT following CFA. HA decreased MHWT following P. gingivalis-L. Conclusion: Gingival BA modulates periodontal mechanical nociception via GPR41 signaling in P. gingivalis-L-induced periodontitis.