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Updated: Dec 28, 2025
Chronic Post-Ischemia Pain Model for Complex Regional Pain Syndrome Type-I in Rats
Published on: January 21, 2020
Mechanisms underlying immobilization-induced muscle pain in rats
Satoshi Oga1,2, Kyo Goto3, Junya Sakamoto4
1Department of Locomotive Rehabilitation Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Introduction:
We investigated the mechanisms underlying immobilization-induced muscle pain in rats.
Methods:
In rat skeletal muscle, pressure pain threshold (PPT) of the gastrocnemius muscle was measured, and nerve growth factor (NGF) level, peripheral nerve fiber density, macrophage number, and interleukin-1β (IL-1β) mRNA expression were examined. An NGF receptor inhibitor was injected intramuscularly to assess the relationship between PPT and NGF levels.
Results:
Immobilization resulted in a decrease in PPT and increases in NGF level, C-fiber density, M1 macrophage number, and IL-1β mRNA expression. Injection of NGF receptor inhibitor reversed the decrease in PPT.
Discussion:
NGF upregulation may be a major contributor to immobilization-induced muscle pain. The increases in C-fiber density, M1 macrophage number, and IL-1β mRNA expression may be related to immobilization-induced muscle pain.
