Premium
Morphological changes in hind limb muscles elicited by adjuvant‐induced arthritis of the rat knee
Author(s) -
Ozawa J.,
Kurose T.,
Kawamata S.,
Yamaoka K.
Publication year - 2010
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/j.1600-0838.2009.00900.x
Subject(s) - hindlimb , medicine , muscle atrophy , atrophy , anatomy , sarcomere , thigh , knee joint , myofibril , inflammation , pathology , myocyte , surgery
We investigated qualitative and quantitative changes in rat hind limb muscles caused by complete Freund's adjuvant (CFA)‐induced knee joint pain. One week after CFA injection, muscle atrophy was induced only on the CFA‐injected side. Wet weight of the rectus femoris (RF) and soleus (SOL) muscles were significantly decreased by 20% and 19%, respectively. The reduction in cross‐sectional areas by CFA was similar for fast and slow muscle fibers in the RF (10% vs 15%, respectively) and SOL muscles (16% vs 16%, respectively). At the light microscopic level, pathological changes were not found in the RF muscles on both sides, although the infiltration of mononuclear cells and muscle regeneration were found in the SOL muscles on CFA‐injected and contralateral control sides. On the other hand, electron microscopy revealed degenerative changes in the RF and SOL muscles on the CFA‐injected side. Interestingly, sarcomere hypercontraction, indicating overexercise, was observed to a limited extent in the SOL muscles on the control side. In conclusions, knee joint pain can trigger the rapid development of muscle atrophy with degenerative changes not only in thigh but also calf muscles. This indicates that early interventions to inhibit joint pain or inflammation may prevent muscle atrophy.