Exercise does not increase cyclooxygenase-2 myocardial levels in young or senescent hearts

• Published in: The journal of physiological sciences 2010-05, Vol.60 (3), p.181-186
• Main Authors: Quindry, John C, French, Joel, Hamilton, Karyn L, Lee, Youngil, Selsby, Josh, Powers, Scott
• Format: Article
• Language: English
• Subjects: Aging; Animals; Cyclooxygenase 2 - metabolism; Exercise Test; Heart; Ischemic Preconditioning - methods; Male; Myocardium - enzymology; Myocardium - metabolism; Nitric Oxide Synthase Type II - metabolism; Physical Conditioning, Animal; Prostaglandins E - metabolism; Rats; Rats, Inbred F344
• ISSN: 1880-6546; 1880-6562
• DOI: 10.1007/s12576-009-0082-2

Increased myocardial cyclooxygenase-2 (COX-2) activity is essential for late phase ischemic preconditioning (IPC). Currently unknown is whether cardioprotection elicited by exercise also involves elevated myocardial COX-2 activity. This investigation tested whether aerobic exercise elevates myocardial COX-2 protein content or enzyme activity in young and senescent male Fisher 344 rats assigned to sedentary or cardioprotective endurance exercise treatments (3 consecutive days of treadmill exercise, 60 min/day @ approximately 70% VO(2)max). Assay of cardiac COX-2 protein content, catalytic activity, and inducible nitric oxide synthase (iNOS) protein content reveal that exercise did not alter COX-2 activity (PGE(2), p = 0.866; PGF1alpha, p = 0.796) or protein levels (p = 0.397) within young or senescent hearts. In contrast, myocardial iNOS, an up-stream mediator of COX-2 expression, was over-expressed by an average of 37% in aged hearts (p = 0.005), though iNOS was not influenced by exercise. Findings reveal exercise does not elevate cardiac COX-2 activity and suggests that mechanisms responsible for cardioprotection differ between IPC and aerobic exercise.