Nociceptive and histomorphometric evaluation of the effects of ozone therapy on the rat masseter muscle in a carrageenan model of myofascial pain

• Published in: Archives of oral biology Vol. 160; p. 105893
• Main Authors: de Souza, Kelvin Borges Rocha, Almeida Guerra, Lysianne Rodrigues de, da Silva Guerreiro, Marcos Lázaro, Casais-e-Silva, Luciana Lyra, Aguiar, Marcio Cajazeira
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-04-2024
• Subjects: Inflammation; Myofascial pain syndromes; Nociception; Ozone; Nociception; Ozone; Inflammation; Myofascial pain syndromes
• ISSN: 0003-9969; 1879-1506
• DOI: 10.1016/j.archoralbio.2024.105893

This study evaluated the effects of intramuscular ozone therapy on nociception, inflammation, and tissue damage caused by the injection of carrageenan in the masseter muscle of rats.
Rat masseter muscles were injected with saline or carrageenan. Seventy-seven adult male rats were divided into six groups: Sal, saline; Car, carrageenan; Ibup + Sal, ibuprofen and saline; Ibup + Car, ibuprofen and carrageenan; O3 + Sal, ozone and saline; and O3 + Car, ozone and carrageenan. The mixture of 5% ozone and 95% oxygen (20 µg/mL) was administered three times in the course of a week. Nociceptive responses in the masseter muscles were measured using a head withdrawal threshold, determined by an electronic von Frey anesthesiometer. The animals were euthanized one or eight days after the carrageenan injection, and the masseters were submitted to histological and histomorphometric analyses.
Mechanical allodynia and inflammation levels were reduced in the Ibup + Car group compared to the other groups. Myonecrosis was similar among carrageenan-treated groups. Picrosirius red stained sections showed more collagen fibers and more regenerating myofibers in the O3 + Car group compared to the other groups. Eight days after carrageenan injection, the O3 + Car group showed neutrophils close to the regenerating myofibers.
Intramuscular ozone therapy did not alleviate mechanical allodynia, and it did not protect the masseter muscle against the deleterious effects produced by carrageenan, probably due to the mode of administration of this therapeutic agent.
•Nociception and inflammation after ozone therapy were measured in the rat masseter.•Intramuscular ozone therapy did not alleviate allodynia after carrageenan.•Ozone therapy did not inhibit inflammation and edema after carrageenan.•Ozone therapy increased the number of regenerating myofibers and collagen fibers.