著者

Hiroki Komiya Kohei Shimizu Kae Ishii Hiroshi Kudo Teinosuke Okamura Kohei Kanno Masamichi Shinoda Bunnai Ogiso Koichi Iwata

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

vol.60, no.4, pp.493-499, 2018 (Released:2018-12-27)

参考文献数

23

被引用文献数

28

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Pulpitis often causes referred pain in opposing teeth. However, the precise mechanism underlying ectopic pain associated with tooth-pulp inflammation remains unclear. We performed the present study to test the hypothesis that functional interactions between satellite glial cells (SGCs) and trigeminal ganglion (TG) neurons are involved in ectopic orofacial pain associated with tooth-pulp inflammation. Digastric muscle electromyograph (D-EMG) activity elicited by administration of capsaicin into the upper second molar pulp (U2) was analyzed to evaluate noxious reflex responses. D-EMG activity was significantly increased in rats with lower first molar (L1) inflammation relative to saline-treated rats. Significantly increased expression of glial fibrillary acid protein (GFAP), a marker of activated glial cells, and connexin 43 (Cx43), a gap-junction protein, was observed in activated SGCs surrounding U2-innervating TG-neurons after L1-pulp inflammation. Daily administration of Gap26, a Cx43-inhibiting mimetic peptide, into the TG significantly suppressed capsaicin-induced D-EMG activity enhancement and reduced the percentage of fluorogold-labeled (U2-innervated) cells that were surrounded by GFAP-immunoreactive (IR) and Cx43-IR cells after L1-pulp inflammation. These findings indicate that tooth-pulp inflammation induces SGC activation and subsequent spread of SGC activation in the TG via Cx43-containing gap junctions. Thus, remote neuron excitability becomes enhanced in the TG following tooth-pulp inflammation, resulting in ectopic tooth-pulp pain in the contralateral tooth.

著者

Kae Ishii Keisuke Hatori Osamu Takeichi Kosuke Makino Kazuma Himi Hiroki Komiya Bunnai Ogiso

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.17-0439, (Released:2018-11-15)

参考文献数

31

被引用文献数

1

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It has been reported that Forkhead box transcription factor class O3a (Foxo3a) is expressed in rheumatoid arthritis, a chronic inflammatory condition accompanied by bone resorption, and plays a role in its pathology. However, it has remained unclear whether Foxo3a is involved in the pathogenesis of periapical granulomas. The present study was performed to compare the expression of Foxo3a in periapical granulomas and healthy gingival tissues. Samples were obtained surgically from patients, and subjected to hematoxylin-eosin staining for histopathologic diagnosis. Two-color immunofluorescence staining was also performed using antibodies against Foxo3a and markers for three types of inflammatory cells: neutrophils, T lymphocytes, and B lymphocytes. This revealed that Foxo3a was expressed in all three cell types in periapical granulomas but not in healthy gingival tissues. Foxo3a was expressed in 82.1%, 78.3%, and 77.5% of neutrophils, T lymphocytes, and B lymphocytes, respectively, and statistical analysis using the Kruskal-Wallis test followed by the Steel-Dwass test showed no significant difference of Foxo3a expression among the three cell types. Our results suggest that Foxo3a transcription factors may be involved in the pathogenesis of periapical granulomas.

著者

Tetsuro Watase Kohei Shimizu Hiroki Komiya Kinuyo Ohara Koichi Iwata Bunnai Ogiso

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.16-0854, (Released:2018-02-26)

参考文献数

21

被引用文献数

9

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A study was conducted to evaluate the mechanisms underlying ectopic orofacial pain associated with tooth pulp inflammation in rats. We observed a significant decrease in the head withdrawal threshold (HWT) response to mechanical and heat stimuli applied to the ipsilateral facial skin upon application of complete Freund’s adjuvant (CFA) to the upper first molar (M1TP) in comparison to application of vehicle. A large number of trigeminal ganglion (TG) neurons showed transient receptor potential vanilloid 1 (TRPV1) immunoreactivity (IR), and some of them were retrogradely labeled with fluorogold injected into the facial skin. A large number of cells showing IR for glial fibrillary acidic protein (GFAP) were observed in the 2nd compared to the 1st or 3rd branch regions of the TG, and TG cells innervating the facial skin were also surrounded by GFAP-IR cells. After administration of TRPV1 antagonist into the facial skin of M1TP CFA-treated rats, the decrease of HWTs in response to mechanical and heat stimulation of the facial skin was significantly reversed. The present findings suggest that the excitability of TG neurons is enhanced upon tooth pulp inflammation, leading to overexpression of TRPV1 in TG neurons innervating the facial skin, and that satellite glial cells are also activated, resulting in the development of ectopic orofacial pain.