Effect of intermittent hypoxic training on HIF gene expression in human skeletal muscle and leukocytes
Résumé
Intermittent hypoxic exposure with exercise
training is based on the assumption that brief exposure to
hypoxia is suYcient to induce beneWcial muscular adaptations
mediated via hypoxia-inducible transcription factors
(HIF). We previously demonstrated (Mounier et al. Med
Sci Sports Exerc 38:1410–1417, 2006) that leukocytes
respond to hypoxia with a marked inter-individual variability
in HIF-1 mRNA. This study compared the eVects of
3 weeks of intermittent hypoxic training on hif gene expression
in both skeletal muscle and leukocytes. Male endurance
athletes (n = 19) were divided into an Intermittent Hypoxic
Exposure group (IHE) and a Normoxic Training group
(NT) with each group following a similar 3-week exercise
training program. After training, the amount of HIF-1
mRNA in muscle decreased only in IHE group (¡24.7%,
P < 0.05) whereas it remained unchanged in leukocytes in
both groups. The levels of vEGF121 and vEGF165 mRNA in
skeletal muscle increased signiWcantly after training only in
the NT group (+82.5%, P < 0.05 for vEGF121; +41.2%,
P < 0.05 for vEGF165). In leukocytes, only the IHE group
showed a signiWcant change in vEGF165 (¡28.2%,
P < 0.05). The signiWcant decrease in HIF-1 mRNA in
skeletal muscle after hypoxic training suggests that transcriptional
and post-transcriptional regulations of the hif-1
gene are diVerent in muscle and leukocytes.