Pergamon-Elsevier Science Ltd. Acta Medica Okayama 0003-9969 59 12 2014 Assessment of intraoral mucosal pain induced by the application of capsaicin 1334 1341 EN Ryuji Terayama Kotaro Maruhama Hiroki Tsuchiya Masahide Mizutani Seiji Iida Tomosada Sugimoto Objective To develop an objective method for assessing nociceptive behaviour in an animal model of capsaicin-induced intraoral pain. Changes in nociceptive responses were also examined after injury to the inferior alveolar nerve (IAN). Design Nociceptive responses evoked by the intraoral application of various doses of capsaicin were analyzed in lightly anaesthetized rats. The number of c-Fos protein-like immunoreactive (Fos-LI) neurons in the medullary dorsal horn (MDH) induced by the intraoral application of capsaicin was measured. Behavioural and c-Fos responses were also examined 14 days after injury to the IAN. Results Larger doses of intraoral capsaicin (1, 10 and 100 μg) induced vigorous licking behaviour and c-Fos response in the MDH in a reproducible manner. The magnitudes of both behavioural activity and the c-Fos response from the 10 and 100 μg doses of capsaicin were significantly greater than that by the 1 μg dose. Injury to the IAN exaggerated the behavioural and c-Fos responses evoked by intraoral capsaicin. Conclusions The intraoral application of capsaicin is a valid and reliable method for studying intraoral pain and hyperalgesia following nerve injury. No potential conflict of interest relevant to this article was reported.

BioMed Central Acta Medica Okayama 3 1 2005 Effect of connective tissue growth factor (CCN2/CTGF) on proliferation and differentiation of mouse periodontal ligament-derived cells EN Masahiro Asano Satoshi Kubota Tohru Nakanishi Takashi Nishida Tomoichiro Yamaai Gen Yosimichi Kazumi Ohyama Tomosada Sugimoto Yoji Murayama Masaharu Takigawa Background: CCN2/CTGF is known to be involved in tooth germ development and periodontal tissue remodeling, as well as in mesenchymal tissue development and regeneration. In this present study, we investigated the roles of CCN2/CTGF in the proliferation and differentiation of periodontal ligament cells (murine periodontal ligament-derived cell line: MPL) in vitro. Results: In cell cultures of MPL, the mRNA expression of the CCN2/CTGF gene was stronger in sparse cultures than in confluent ones and was significantly enhanced by TGF-β. The addition of Recombinant CCN2/CTGF (rCCN2) to MPL cultures stimulated DNA synthesis and cell growth in a dose-dependent manner. Moreover, rCCN2 addition also enhanced the mRNA expression of alkaline phosphatase (ALPase), type I collagen, and periostin, the latter of which is considered to be a specific marker of the periosteum and periodontium; whereas it showed little effect on the mRNA expression of typical osteoblastic markers, e.g., osteopontin and osteocalcin. Finally, rCCN2/CTGF also stimulated ALPase activity and collagen synthesis. Conclusion: These results taken together suggest important roles of CCN2/CTGF in the development and regeneration of periodontal tissue including the periodontal ligament. No potential conflict of interest relevant to this article was reported.