Effect of Carrageenan-induced Inflammatory Muscle Pain on Gastrocnemius Muscle Tendon in the Rat

Abstract

Background: It has been suggested that muscle pain may induce skeletal muscle tendon damage, but the mechanism of this process is not known. The purpose of this study was to investigate gastrocnemius muscle tendon damage on Sprague-Dawley rats after inducing inflammatory muscle pain with carrageenan. Methods: Rats were anesthetized with sevoflurane. Muscle pain was induced by injecting 0.1 ml of carrageenan into the gastrocnemius muscle. Rats were killed on 48 hours after carrageenan injection. Muscle tendons were fixed in 10% neural buffered formalin (NBF), dehydrated, embedded, and sectioned at 4 Sections were then stained with phosphotungstic acid hematoxylin(PTAH), mounted, and observed under a light microscope. Results: Carrageenan-induced inflammatory muscle pain was associated with reduced tendon fiber and fibroblast numbers. Conclusions: This finding suggests that carrageenan-induced inflammatory muscle pain damages the gastrocnemius muscle tendon in the rat by reducing tendon fiber and fibroblast numbers.