Freie Mitteilungen 3
4. November 2022, 11:00 - 12:00, Gartensaal 2
Effects of moderate- and high-intensity exercise training in normoxia or hypoxia on atherosclerosis in mice.
L. Wang1, J. Lavier2, K. Bouzourène2, N. Rosenblatt-Velin2, L. Mazzolai2, Y. Zhang1, G. Millet2, M. Pellegrin2, Presenter: M. Pellegrin2 (1Beijing, 2Lausanne)
Moderate-intensity continuous training (MICT) is an effective strategy to reduce cardiovascular risk and atherosclerosis. High-intensity interval training (HIIT) has emerged as an alternative to MICT because of its similar or superior efficacy on cardiovascular parameters. Exercising in hypoxia may have potential clinical applications for patients with cardiovascular diseases, however the effect of hypoxic exercise, in particular the effect of hypoxic HIIT, on atherosclerosis development remains unknown. In this study, we compared the effects of MICT and HIIT in normoxia (FiO2 21%) or hypoxia (FiO2 11.2%) on atherosclerosis in adult male Apolipoprotein E Knockout (ApoE KO) mice.
Mice performed 3 sessions of exercise training per week. MICT consisted in treadmill running for 40 min at 40% of maximal running speed (MAS) while HIIT consisted in 4 sets of 5 x 10-s sprints treadmill running at 100% of MAS with 20 s of rest between sprints and 5 min between sets. Prevention study: ApoE KO mice were fed a high-fat diet (HFD) for 6 weeks. At the start of HFD, mice were randomly allocated into six groups: sedentary in normoxia (SED-N), sedentary in hypoxia (SED-H), MICT in normoxia (MICT-N), MICT in hypoxia (MICT-H), HIIT in normoxia (HIIT-N), and HIIT in hypoxia (HIIT-H). Therapeutic study: ApoE KO mice were fed HFD for a total of 18 weeks and were randomly allocated during the last 6 weeks to the same 6 groups than in the prevention study. Histological sections of the aortic sinus were processed for quantification of total atherosclerotic plaque area.
Prevention study: Atherosclerotic plaque area was significantly reduced both in MICT-N and HIIT-N compared to SED-N (p<0.001). SED-H mice exhibited smaller plaque area than SED-N (p<0.05). No significant differences were observed between MICT-H and MICT-N, as well as between HIIT-H and HIIT-N. Plaque area did not significantly differ between the three hypoxic groups. Therapeutic study: No significant differences were found between the six groups.
MICT and HIIT, independently of normoxic or hypoxic conditions, were equally effective at preventing the development of atherosclerotic plaques in ApoE KO mice. Hypoxia did not potentiate the beneficial preventive effect of exercise training on atherosclerosis. However, passive hypoxic exposure was efficient in preventing atherosclerotic plaques development in sedentary mice.