Objectives: The present study evaluated the involvement of the Annexin 1/FPR2/ALX receptor in the antihyperalgesic effect induced by electroacupuncture (EA) in an animal model of persistent peripheral inflammation.
Swiss male mice underwent intraplantar (i.pl.) injection with complete Freund's adjuvant (CFA). Mechanical hyperalgesia was assessed by the von Frey test. Animals were treated with EA (2-10Hz, ST36-SP6) or subcutaneous BML-111 injection (FPR2/ALX an analog of lipoxin A4) for 5 consecutive days. In another set of experiments, on the first and fifth days after CFA injection, animals received i.pl. WRW4 (FPR2/ALX antagonist) or naloxone (non-selective opioid receptor antagonist) before EA or BML-111 treatment. Expression of the FPR2/ALX and Annexin 1 (AnxA1) in the paw was performed on the second day after CFA injection by the Western Blotting technique.
Endogenous increase of FPR2/ALX and decrease of AnxA1 expression at the inflammation site are involved in CFA-induced inflammatory pain. EA treatment produces its antihyperalgesic effect through AnxA1/FPR2/ALX pathway. This seems to be triggered by the activation of FPR2 and a cross-talk with the opioid system.
Daniel Fernandes Martins– Professor, University of Southern Santa Catarina
Cintia Vieira– Professor, UNISUL
Daiana Cristina Salm– Professor, University of Southern Santa Catarina
Verônica Horewics– Research, UNISUL
Daniela Ludtke– PhD Student, UNISUL
Aline Emer– Ms, UNISUL
Júlia Koerich– Student, UNISUL
Gustavo Mazzardo– Student, UNISUL
Sayron Elias– Student, UNISUL
Anna Paula– Professor, UNISUL
Lisandro Ceci– Student, UNISUL
Afonso Salgado– Associate Researcher, University of Southern Santa Catarina
Francisco Cidral Filho– Associate Researcher, University of Southern Santa Catarina - Brazil
Leidiane Martins– Doutora, UFSC
Ari Moré– Assistent Professor, UFSC