Research progress in bone metabolism in the hypoxic environment / 中国组织工程研究

ABSTRACT

BACKGROUND:It has been reported that human aerobic endurance, cardiovascular system, blood constituent, immune system, neuroendocrine system, free radical antioxidant system, and acid-base balance system can be influenced under hypoxic conditions. However, very little is known regarding bone metabolism under hypoxic conditions and the underlying mechanisms. OBJECTIVE:To summarize the effects of hypoxic conditions on bone metabolism from the views of hypoxia inducible factors, osteblasts and osteoclasts, and the effects of exercise training under hypoxic conditions on the skeleton, contributing to understanding the theoretical advantages and disadvantages of altitude training. METHODS:A computer-based online search was conducted in CNKI and PubMed databases from January 2000 to September 2015 using the keywords“hypoxia environment, hypoxia inducible factors, bone metabolism, exercise, altitude training”to screen the relevant English and Chinese literatures. A total of 233 literatures were screened and final y 46 eligible literatures were included. RESLUTS AND CONCLUSION:The effects of hypoxic conditions on bone metabolism are complex, which are mainly linked to hypoxia inducible factors, osteblasts and osteoclasts. Hypoxia-inducible factor 1 is considered to influence the skeleton by promoting the bone growth induced by vascular endothelial growth factor and directly affecting the osteblasts and osteoclasts. Additional y, hypoxia-inducible factor 1 has been shown to enhance osteoclast-mediated bone resorption. The balance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption is disturbed under hypoxic conditions. We need to pay attention to the training period and intensity at altitude because altitude training may not benefit the bone metabolism.