Orofacial anti-hypernociceptive effect of citral in acute and persistent inflammatory models in rats

• Autor(a) principal: Santos, Bruna M.
• Data de Publicação: 2023
• Outros Autores: Santos, Wanderson S., Solon, Isabelly G., Garcia, Felipe S., Emilio-Silva, Maycon T. [UNESP], Jesus, Aline A., Hiruma-Lima, Clélia A. [UNESP], Nascimento, Glauce C., Cárnio, Evelin C., Branco, Luiz G.S.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1016/j.archoralbio.2023.105734; http://hdl.handle.net/11449/249085
• topic: Complete Freund's Adjuvant; Formalin; Inflammation; Orofacial pain; Temporomandibular disorders; Trigeminal system

Orofacial pain has significant psychological and physiological effects. Citral (3,7-dimethyl-2,6-octadienal) is the main component of Cymbopogon citratus (DC) Stapf, an herb with analgesic properties. Although citral has been considered a potent analgesic, its putative effects on orofacial pain are still unknown. Objective: The objective of this study is to test the hypothesis that citral modulates orofacial pain using two experimental models: formalin-induced hyperalgesia in the vibrissae area and during persistent temporomandibular hypernociception using Complete Freund's Adjuvant - CFA test. Methods: For the formalin test, citral (100 and 300 mg/kg, oral gavage) or its vehicle (Tween 80, 1 %) were given 1 h before the formalin injection subcutaneously (sc) into the vibrissae area. For the CFA model, we analyzed the prophylactic (100 mg/kg of citral by oral gavage, 1 h before CFA injection) and the chronic therapeutic (citral treatment 1-hour post-CFA injection and daily post-CFA injection) effect of citral or its vehicle in animals treated with CFA for 8 days. Results: Citral caused a decrease in formalin-induced local inflammation and the time spent performing nociceptive behavior in a dose-dependent fashion. Similarly, prophylactic and therapeutic citral treatment decreased the CFA-induced persistent mechanical hypernociception in the temporomandibular area. Conclusion: Our data strengthen the notion that citral plays a powerful antinociceptive role by decreasing orofacial hypernociception in formalin and CFA models.