The Effects of Exercise Intensity Difference on Bone Metabolic Markers and Cytokines of the RANKL/RANK/OPG System in Korean Osteopenia Elderly Women

Abstract

PURPOSE Regular exercise augments the bone mineral density in postmenopausal elderly women. However, its acute effects by different intensities on bone metabolic markers and cytokines of the RANKL/RANK/OPG system have not been determined. Our aim was to investigate the effects exercise intensity difference on these markers and RANKL/RANK/OPG system in Korean osteopenia elderly women. METHODS Twelve osteopenia elderly women (T-score -2.46±0.48; aged 68.17±3.04 years) examined these markers and RANKL/RANK/OPG system responses to acute high (80% VO2max ; HIGH group), low (40% VO2max; LOW group) intensity with a cycle ergometer, and sedentary rest (CON group) in a randomized, cross-over repeated measures design. The concentrations of bone metabolic markers and cytokines measured before, immediately after and then recovery 60 minutes after exercise. mRNA expressions of RANKL & OPG from PBMC were also measured at same times. RESULTS There were no significant changes in the serum CTx and RANKL, and mRNA expression of RNAKL, indicating bone resorption (NS). On the other hand, although the serum OPG showed significant change in high intensity (p=.027; group×time), the serum OC showed significant change in low intensity (p=.044; group×time), indicating bone formation, respectively. CONCLUSIONS These results suggest that a single bout exercise might effect on bone formation alone with OPG responds to high intensity, OC responds to low intensity. Additional studies are needed on the difference in change between OC and OPG due to exercise intensity.

Keywords

• intensity
• osteopenia
• oc
• ctx
• rankl
• rank