Tetracycline therapy for muscle atrophy due to immobilization.
Certain proteins such as matrix metalloproteinase -2(MMP-2) and heat shock protein 70(HSP-70) play a role during the degradation process. We hypothesized that tetracycline can be used to reduce tissue degradation in skeletal muscles exposed to immobilization. The right knee of old rats (20-months-old) was immobilized by a rigid external fixator (EF) device for 1, 2, 3 and 4 weeks. Aqueous Tetracycline solution was administrated 3 times a week, following 2 days after the EF was constructed. Control group I was immobilized for 3 weeks, did not receive tetracycline but did received saline injection, and control group II only received tetracycline for 3 weeks. MMP-2 and HSP-70 protein and mRNA levels in the gastrocnemius and soleus muscles were analyzed at the molecular level by RT-PCR and the protein level using SDS-PAGE gels and western blots. We have shown that rats treated by Tetracycline reduce the MMP-2 expression and HSP-70. Theses changes mainly occurred in type IIb and type IIa muscle fibers. Tetracycline administration has beneficial effect on expression of enzymes involved in protein degradation. This may suggest a protective effect on protein degradation during immobilization.
Carmeli
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E
Department of Physical Therapy, Stanley Steyer School of Health Professions, Tel Aviv University, Ramat Aviv 69978, Israel. elie@post.tau.ac.il
Kodesh
E
E
Nemcovsky
C
C
D000818:Animals; D015153:Blotting, Western; D015870:Gene Expression / Q000187:drug effects*; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000187:drug effects; D007103:Immobilization / Q000009:adverse effects; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D009133:Muscular Atrophy / Q000188:drug therapy* / Q000209:etiology; D011500:Protein Synthesis Inhibitors / Q000627:therapeutic use*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013752:Tetracycline / Q000627:therapeutic use*
D018840:HSP70 Heat-Shock Proteins; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D020778:Matrix Metalloproteinase 2; D013752:Tetracycline