Early prevention of carrageenan-induced peripheral/spinal inflammation suppresses microglial hyperreactivity in the trigeminal spinal subnucleus caudalis and alleviates chronic facial nociception

In this study, we investigated the mechanisms underlying carrageenan-induced chronic pain and the therapeutic effect of the anti-inflammatory drug meloxicam. Rats were injected with 3 % carrageenan into the masseter muscle. These rats exhibited acute and chronic hypersensitivity to mechanical stimul...

Full description

Saved in:
Bibliographic Details
Main Authors: Toru Yamamoto, Mitsuhiro Yoshida, Yuhei Koyama, Yatendra Mulpuri, Eiji Imado, Kana Oue, Mitsuru Doi, Yoshitaka Shimizu, Naotaka Kishimoto, Hiroshi Hanamoto, Kenji Seo
Format: Article
Language:English
Published: Elsevier 2025-01-01
Series:Heliyon
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2405844024176335
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In this study, we investigated the mechanisms underlying carrageenan-induced chronic pain and the therapeutic effect of the anti-inflammatory drug meloxicam. Rats were injected with 3 % carrageenan into the masseter muscle. These rats exhibited acute and chronic hypersensitivity to mechanical stimuli for 6 weeks after injection. Pre-treatment with meloxicam prevented carrageenan-induced chronic hypersensitivity. Furthermore, minocycline and dexamethasone, but not acetaminophen, suppressed carrageenan-induced hypersensitivity in the chronic phase. Microglial reactivity in the trigeminal spinal subnucleus caudalis (Vc) was assessed by immunohistochemistry 3 days after treatment. The reactivity of microglial cells in the Vc was increased in carrageenan-treated rats compared with vehicle-injected rats. Meloxicam and dexamethasone, but not acetaminophen, prevented carrageenan-induced microglial hyperreactivity in the Vc. These results suggest that early prevention of peripheral/spinal inflammation suppresses microglial reactivity in the Vc and inhibits the development of orofacial chronic pain.
ISSN:2405-8440