Myocardial heat shock protein 70 expression in young and old rats after identical exercise programs.
Synthesis of inducible heat shock protein 70 (HSP70) is impaired in aged animals following acute stresses including exercise. In this study we determined whether aging affects expression of this cytoprotective protein following chronic exercise participation. Male Fischer 344 rats, final ages 6 and 24 months, exercised identically for 10 weeks on a treadmill (15 degrees incline, 15 m/min for up to 60 minutes, 5 days/week). In 6-month-old animals, exercise increased HSP70 in heart (44%), liver (216%), and skeletal muscle (126%) (p <.05 vs sedentary). In 24-month-old animals, exercise increased HSP70 in muscle (69%), but not in heart or liver. In heart, antioxidant enzyme activities and HSP70 messenger RNA were measured and found to be unaffected by exercise at both ages. Our results indicate an age-related decrease in HSP70 production in heart and liver following chronic exercise. Furthermore, the aged heart does not increase its antioxidant enzyme defenses to compensate for the HSP70 deficit.
Starnes
Joseph W
JW
Department of Kinesiology and Health Education, University of Texas, Austin, TX, USA. jstarnes@mail.utexas.edu
Choilawala
Alafia M
AM
Taylor
Ryan P
RP
Nelson
Mathew J
MJ
Delp
Michael D
MD
D000375:Aging / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001483:Base Sequence; D002374:Catalase / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D003576:Electron Transport Complex IV / Q000378:metabolism; D015870:Gene Expression; D005979:Glutathione Peroxidase / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics*; D008099:Liver / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D005082:Physical Exertion / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D013482:Superoxide Dismutase / Q000378:metabolism
D000975:Antioxidants; D018076:DNA, Complementary; D018840:HSP70 Heat-Shock Proteins; D012333:RNA, Messenger; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D003576:Electron Transport Complex IV