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. 중 OC와 CTx의 비율(OC/CTx ratio)이 이용되고 있으며, OC/CTx ratio 의 upregulation은 골형성을 촉진하는 것으로 판단할 수 있다[55,56]. 본 연구에 있어서 혈중 농도의 OC/CTx ratio에서도 유의미한 변화가 없었으며, 1회성의 운동으로는 OC/CTx ratio의 변화를 야기시키지 않 을 가능성이 시사되었다. 또한 본 연구의 대상자들은 평소 운동 습관 이 없는 고령의 골감소증 여성을 대상으로 하고 있어, 건강한 여성들 과는 운동에 대한 반응이 다르게 나타날 가능성도 상정된다. 추후 다 양한 대상자를 통한 검토가 필요할 것으로 사료된다. 결 론 골감소증 고령 여성을 대상으로 1회성의 저강도(40% VO2max)와 고 강도(80% VO2max) 운동에 따른 혈중 골대사 표지자 및 RANKL/RANK/ OPG 시스템 사이토카인을 검토하였다. 그 결과 골흡수를 나타내는 혈중 CTx, RANKL 및 RANKL, RANK mRNA에서는 유의한 변화가 나타나지 않았지만, 골형성을 나타내는 혈중 OC는 저강도에서, 혈중 OPG는 고강도에서 변화하는 것이 밝혀져, 1회성 운동은 골형성을 자 극할 가능성이 시사되었다. 단, 운동강도에 따른 OC와 OPG의 변화 차에 대해서는 추후 검토가 필요할 것으로 사료되었다.

RANKL/RANK/OPG Pathway: A Mechanism Involved in Exercise‐Induced Bone Remodeling

“…e intensity in these results depends on the distance and duration of the path [111]. After a performance period with 80% VO2max and 40% VO2max intensity, OPG levels in serum have increased just under high-intensity exercise conditions in elderly women [112]. Based on a clinical trial done by Mezil et al, the low-impact high-intensity exercise would increase OPG, RANKL, and ALP levels in male university students [88].…”

Effects of 12-week combined exercise on RANKL/RANK/OPG signaling and bone-resorption cytokines in healthy college females

“…We also elucidated the effects of high- (80% VO 2max ) and low-intensity (40% VO 2max ) acute cycle ergometer exercise. As a result, the concentration of serum OPG was increased, but no change was observed in levels of the other bone metabolic cytokines after high-intensity exercise in elderly osteoporotic women 17 . Furthermore, serum concentrations of RANKL and OPG and the mRNA expression of RANK, RANKL, and OPG were not significantly changed upon acute treadmill exercise training reaching 60 or 80% VO2max in healthy college female subjects 18 .…”