Impaired aerobic capacity in hypercholesterolemic mice: partial reversal by exercise training.
The present study assessed whether impaired aerobic capacity previously observed in hypercholesterolemic mice is reversible by exercise training. Seventy-two 8-wk-old female C57BL/6J wild-type (+, n = 42) and apolipoprotein E-deficient (-, n = 30) mice were assigned to the following eight interventions: normal chow, sedentary (E+, n = 17; E-, n = 8) or exercised (E+ex, n = 13; E-ex, n = 7) and high-fat chow, sedentary (E+chol, n = 6; E-chol, n = 8) or exercised (E+chol-ex, n = 6; E-chol-ex, n = 7). Mice were trained on a treadmill 2 x 1 h/day, 6 days/wk, for 4 wk. Cholesterol levels correlated inversely with maximum oxygen uptake (r = -0.35; P < 0. 02), which was blunted in all hypercholesterolemic sedentary groups (all P < 0.05). Maximum oxygen uptake improved in all training groups but failed to match E+ex (all P < 0.05). Vascular reactivity and nitric oxide (NO) synthesis correlated with anaerobic threshold (r = 0.36; P < 0.025) and maximal distance run (r = 0.59; P < 0.007). We conclude that genetically induced hypercholesterolemia impairs aerobic capacity. This adverse impact of hypercholesterolemia on aerobic capacity may be related to its impairment of vascular NO synthesis and/or vascular smooth muscle sensitivity to nitrovasodilators. Aerobic capacity is improved to the same degree by exercise training in normal and genetically hypercholesterolemic mice, although there remains a persistent difference between these groups after training.
Niebauer
J
J
Section of Vascular Medicine, Division of Cardiovascular Medicine, Stanford University, Stanford, California 94305, USA.
Maxwell
A J
AJ
Lin
P S
PS
Tsao
P S
PS
Kosek
J
J
Bernstein
D
D
Cooke
J P
JP
D000332:Aerobiosis; D000818:Animals; D001021:Aortic Valve / Q000473:pathology; D001057:Apolipoproteins E / Q000172:deficiency; D002784:Cholesterol / Q000097:blood; D004730:Endothelium, Vascular / Q000473:pathology; D005260:Female; D006937:Hypercholesterolemia / Q000097:blood / Q000473:pathology / Q000503:physiopathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008855:Microscopy, Electron, Scanning; D010101:Oxygen Consumption / Q000502:physiology*; D010805:Physical Conditioning, Animal; D012016:Reference Values; D014666:Vasomotor System / Q000503:physiopathology
D001057:Apolipoproteins E; D002784:Cholesterol