title: Cardiac troponin T alterations in myocardium and serum of rats after stressful, prolonged intense exercise.
abstract: The goal of this study was to determine whether the stress of forced exercise would result in injury to the myocardium. Male rats with 8% of body weight attached to the tail were forced to swim 3.5 h (3.5S), forced to swim 5 h (5S), or pretrained for 8 days and then forced to swim 5 h (T5S). Rats were killed immediately after they swam (0 h PS) and at 3 h (3 h PS), 24 h (24 h PS), and 48 h after they swam (48 h PS). Tissue homogenates of the left ventricle were analyzed by Western blot analysis for cardiac troponin T (cTnT). Serum cTnT was quantified by immunoassay. Results indicated that, in the 3.5S, 5S, and T5S groups, serum cTnT was significantly (P < 0.01) increased at 0 and 3 h PS. The 5S group demonstrated a greater increase in serum cTnT than the 3.5S group (P < 0.01) and the T5S group (P < 0.01) at 0 h PS. Western blot analysis indicated significant decreases (P < 0. 01) in myocardial cTnT in the 5S group only at 0 h PS (P < 0.01) and 3 h PS (P < 0.05). Histological evidence of localized myocyte damage demonstrated by interstitial inflammatory infiltrates consisting of neutrophils, lymphocytes, and histiocytes, as well as vesicular nuclei-enlarged chromatin patterns, was observed in left ventricle specimens from the 5S group at 24 and 48 h PS. Our findings demonstrate that stressful, forced exercise induces alterations in myocardial cTnT and that training before exercise attenuates the exercise-induced heart damage.
authors.affiliation: Division of Kinesiology, School of Kinesiology and Leisure Studies, University of Minnesota, Minneapolis 55455, Minnesota, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: R C
authors.initials: RC
authors.lastname: Serfass
authors.forename: S M
authors.initials: SM
authors.lastname: Mackey-Bojack
authors.forename: K L
authors.initials: KL
authors.lastname: Kelly
authors.forename: J L
authors.initials: JL
authors.lastname: Titus
authors.forename: F S
authors.initials: FS
authors.lastname: Apple
mesh_terms: D000818:Animals; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009206:Myocardium / Q000378:metabolism*; D010807:Physical Endurance; D051381:Rats; D017207:Rats, Sprague-Dawley; D013312:Stress, Physiological / Q000097:blood*; D013997:Time Factors; D020107:Troponin T / Q000097:blood / Q000378:metabolism*
chemical_list: D020107:Troponin T