title: Apoptotic adaptations from exercise training in skeletal and cardiac muscles.
abstract: The effect of exercise on apoptosis in postmitotic tissues is not known. In this study, we investigated the effect of regular moderate physical activity (i.e., exercise training) on the extent of apoptosis in rat skeletal and cardiac muscles. Adult Sprague Dawley rats were trained (TR) 5 days weekly for 8 wk on treadmill. Sedentary rats served as controls (CON). An ELISA was used to detect mono- and oligonucleosome fragmentation as an indicator of apoptosis. Bcl-2, Bax, Apaf-1, AIF, cleaved PARP, cleaved caspase-3, cleaved/active caspase-9, heat shock protein (HSP)70, Cu/Zn-SOD, and Mn-SOD protein levels were determined by Western analyses. Bcl-2 and Bax transcript contents were estimated by RT-PCR. A spectrofluorometric assay was used to determine caspase-3 activity. DNA fragmentation in ventricles of the TR group decreased by 15% whereas that in soleus of the TR group tended to decrease (P=0.058) when compared with CON group. Protein contents of Bcl-2, HSP70, and Mn-SOD increased in both soleus and ventricle muscles of TR animals when compared with CON animals. Apaf-1 protein content in the soleus of TR animals was lower than that of CON animals. Bcl-2 mRNA levels increased in both ventricle and soleus muscles of TR animals, and Bax mRNA levels decreased in the soleus of TR animals when compared with CON animals. Furthermore, HSP70 protein content was negatively correlated to Bax mRNA content and was positively correlated to Bcl-2 protein and mRNA contents. Mn-SOD protein content was negatively correlated to the apoptotic index, and caspase-3 activity and was positively correlated to Bcl-2 transcript content and HSP70 protein content. These data suggest that exercise training attenuates the extent of apoptosis in cardiac and skeletal muscles.
authors.affiliation: Laboratory of Muscle Biology and Sarcopenia, Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, West Virginia 26506-9227, USA .
authors.forename: Parco M
authors.initials: PM
authors.lastname: Siu
authors.forename: Randall W
authors.initials: RW
authors.lastname: Bryner
authors.forename: Julie K
authors.initials: JK
authors.lastname: Martyn
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Alway
mesh_terms: D000818:Animals; D017209:Apoptosis; D051033:Apoptosis Inducing Factor; D053477:Apoptotic Protease-Activating Factor 1; D020169:Caspases / Q000032:analysis; D053938:DNA Fragmentation; D005420:Flavoproteins / Q000032:analysis; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis; D006352:Heart Ventricles; D008297:Male; D008565:Membrane Proteins / Q000032:analysis; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism; D009124:Muscle Proteins / Q000032:analysis*; D018482:Muscle, Skeletal / Q000166:cytology* / Q000378:metabolism; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism; D009928:Organ Specificity; D018384:Oxidative Stress; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011065:Poly(ADP-ribose) Polymerases / Q000032:analysis; D011506:Proteins / Q000032:analysis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013482:Superoxide Dismutase / Q000032:analysis; D051028:bcl-2-Associated X Protein
chemical_list: C494831:Aifm1 protein, rat; C506594:Apaf1 protein, rat; D051033:Apoptosis Inducing Factor; D053477:Apoptotic Protease-Activating Factor 1; C494828:Bax protein, rat; D005420:Flavoproteins; D018840:HSP70 Heat-Shock Proteins; D008565:Membrane Proteins; D009124:Muscle Proteins; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D051028:bcl-2-Associated X Protein; D013482:Superoxide Dismutase; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases