Expression and activity of cyclooxygenase isoforms in skeletal muscles and myocardium of humans and rodents

Marco Testa, Bianca Rocca, Lucia Spath, Franco O. Ranelletti, Giovanna Petrucci, Giovanni Ciabattoni, Fabio Naro, Stefano Schiaffino, Massimo Volpe, Carlo Reggiani

Research output: Contribution to journalArticlepeer-review

Abstract

Conflicting data have been reported on cyclooxygenase (COX)-1 and COX-2 expression and activity in striated muscles, including skeletal muscles and myocardium, in particular it is still unclear whether muscle cells are able to produce prostaglandins (PGs). We characterized the expression and enzymatic activity of COX-1 and COX-2 in the skeletal muscles and in the myocardium of mice, rats and humans. By RT-PCR, COX-1 and COX-2 mRNAs were observed in homogenates of mouse and rat hearts, and in different types of skeletal muscles from all different species. By Western blotting, COX-1 and -2 proteins were detected in skeletal muscles and hearts from rodents, as well as in skeletal muscles from humans. Immunoperoxidase stains showed that COX-1 and -2 were diffusely expressed in the myocytes of different muscles and in the myocardiocytes from all different species. In the presence of arachidonic acid, which is the COX enzymatic substrate, isolated skeletal muscle and heart samples from rodents released predominantly PGE2. The biosynthesis of PGE2 was reduced between 50 and 80% (P <0.05 vs. vehicle) in the presence of either COX-1- or COX-2-selective blockers, demonstrating that both isoforms are enzymatically active. Exogenous PGE2 added to isolated skeletal muscle preparations from rodents did not affect contraction, whereas it significantly fastened relaxation of a slow type muscle, such as soleus. In conclusion, COX-1 and COX-2 are expressed and enzymatically active in myocytes of skeletal muscles and hearts of rodents and humans. PGE2 appears to be the main product of COX activity in striated muscles.

Original languageEnglish
Pages (from-to)1412-1418
Number of pages7
JournalJournal of Applied Physiology
Volume103
Issue number4
DOIs
Publication statusPublished - Oct 2007

Keywords

  • Cyclooxygenases
  • Muscle
  • Myocardium
  • Prostaglandins

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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