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Expression of matrix metalloproteinases, inhibitor, and acid phosphatase in muscles of immobilized hindlimbs of rats
Author(s) -
Reznick Abraham Z.,
Menashe Ofir,
BarShai Marina,
Coleman Raymond,
Carmeli Eli
Publication year - 2003
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.10277
Subject(s) - hindlimb , matrix metalloproteinase , acid phosphatase , extracellular matrix , zymography , muscle atrophy , anatomy , western blot , atrophy , chemistry , endocrinology , biology , medicine , biochemistry , enzyme , skeletal muscle , gene
External fixation procedures of limb immobilization provide excellent experimental models to study mechanisms involved in muscle disuse atrophy and recovery. Female Wistar rats (7–8 months old) had their right hindlimbs immobilized by an external fixation procedure for 5, 10, 21, and 30 days. Muscle mass of the gastrocnemius and quadriceps muscles was reduced by 41–46% in comparison with contralateral nonimmobilized legs. Acid phosphatase activities were significantly increased after 21 and 30 days of hindlimb immobilization. Histochemical staining for acid phosphatase activities increased in myofibers after the external fixation and also in macrophages in the adjacent extracellular matrix. Matrix metalloproteinase (MMP‐2 and MMP‐9) activities assessed by gel zymography and also a tissue inhibitor of metalloproteinases (TIMP‐1) assessed by Western blot were elevated in the immobilized hindlimb muscles. Our study demonstrated that metalloproteinases are expressed relatively late after limb immobilization and appear to be responsible to a large degree for degradation of the extracellular matrix in experimental disuse atrophy. Muscle Nerve 27: 51–59, 2003